KR20230166307A - Acousto-optic tunable filter using a mercurous bromide crystal - Google Patents

Abstract

An acousto-optical variable filter using mercury halide crystals is disclosed. The variable acousto-optic filter according to the present invention is formed of a mercury halide material and has a polyhedral shape with an upper surface, a lower surface, and a plurality of side surfaces, and the upper surface, the lower surface, and the plurality of side surfaces all have a Miller index for unit length n. Acousto-optics formed to be inscribed in a virtual rectangular parallelepiped whose first side is 35n long on a surface located on the [001] plane and whose second side adjacent to the first side has a length of 21n on a surface located on the Miller index [110] plane. device; and a transducer coupled to one of the plurality of sides and configured to radiate sound waves, wherein the plurality of sides form an angle between 16.5 and 17.5 degrees with respect to the Miller index plane, and have a length of 24n. A first side with; a second side that is bent and connected to one side of the first side, is located on the Miller index [110] plane, and has a length of 4n; A third side is bent at one side of the second side, extends between a surface located on the Miller index [110] plane of the virtual rectangular parallelepiped, and a surface located on the Miller index [001] plane, and has a length of 20n. ; and a fourth side that is bent and connected to the other side of the first side and has a length of 16n, wherein the transducer is coupled to one side of the first side and has a length of 8n or less along the longitudinal direction of the first side. It is characterized by having a length of.

Description

Acousto-optical variable filter using mercury halide crystals {ACOUSTO-OPTIC TUNABLE FILTER USING A MERCUROUS BROMIDE CRYSTAL}

The present invention relates to a bandpass filter, and specifically to an acousto-optical tunable filter (AOTF) that can detect wavelengths in the long-wavelength infrared band using mercury halide crystals.

The acousto-optic effect refers to a phenomenon in which the refractive index of light changes within a medium when an acoustic wave is applied to the medium. In other words, when sound waves or waves in the ultrasonic band are applied to a transparent medium, this periodically changes the refractive index of the medium. Depending on the change in refractive index, the optical beam passing through the medium may be diffracted into -2nd, -1st, 0th, 1st, and 2nd diffracted light, including 0th order diffracted light that passes as is. there is. An acousto-optic tunable filter (AOTF) uses this acousto-optic effect to separate and detect light of a specific wavelength included in an incident light beam.

By controlling the spectral characteristics electronically, the acousto-optic variable filter not only increases the probability of detection by minimizing the image acquisition time, but also enables measurement of the polarization characteristics of the subject and simultaneous acquisition of multi-wavelength images. If a tunable acousto-optic filter can be used to detect light in the long-wave infrared (LWIR) band, it will be particularly useful as it can be applied to a variety of applications such as remote detection of biochemical agents, monitoring of the spread of pollutants, and mineral exploration. However, there are not many materials that exhibit excellent acousto-optic properties in the long-wave infrared band, so there is a great need for the development of a tunable acousto-optic filter applicable in that band.

In addition, in an acousto-optic variable filter, the angles formed by the surface of the acousto-optic variable filter, such as acoustic angle, walk-off angle, and diffraction angle, are important. Because it is manufactured by polishing the surface of a crystal that exhibits acousto-optic properties, it is difficult to manufacture an acousto-optic variable filter focusing on the angle of the surface.

Therefore, the present invention was developed to solve the above-mentioned problems, and one aspect of the present invention is to provide a variable acousto-optic filter capable of detecting light in the long-wavelength infrared band.

In addition, one aspect of the present invention is to provide a variable acousto-optic filter that can be manufactured in an easier manner by designing the acousto-optic variable filter based on the surface dimensions of the acousto-optic crystal.

Other objects of the present invention will become clearer through the examples described below.

The variable acousto-optic filter according to one aspect of the present invention is formed of a mercury halide material and has a polyhedral shape with an upper surface, a lower surface, and a plurality of side surfaces, and for unit length n, the upper surface, the lower surface, and the plurality of side surfaces are All are inscribed in an imaginary rectangular parallelepiped whose length of the first side is 35n on the surface located on the Miller index [001] plane, and where the length of the second side adjacent to the first side is 21n on the surface located on the Miller index [110] plane. Formed acousto-optic element; and a transducer coupled to one of the plurality of sides and configured to radiate sound waves, wherein the plurality of sides form an angle between 16.5 and 17.5 degrees with respect to the Miller index plane, a first side with a length of 24n; a second side that is bent and connected to one side of the first side, is located on the Miller index [110] plane, and has a length of 4n; A third side is bent at one side of the second side, extends between a surface located on the Miller index [001] plane of the virtual rectangular parallelepiped, and a surface located on the Miller index [110] plane, and has a length of 20n. ; and a fourth side that is bent and connected to the other side of the first side and has a length of 16n, wherein the transducer is coupled to one side of the first side and extends along the longitudinal direction of the first side. It can have a length of 8n or less.

The above variable acousto-optic filter may include one or more of the following embodiments. For example, the plurality of side surfaces may be bent and connected to one side of the third side surface, and may further include a fifth side surface located on the Miller index [001] plane.

In some embodiments, the fifth side may have a length of 8n, and the plurality of sides may further include a sixth side extending between one side of the fifth side and the other side of the fourth side.

The variable acousto-optic filter according to another aspect of the present invention is formed of a mercury halide material and has a polyhedral shape with an upper surface, a lower surface, and a plurality of side surfaces, and the upper surface, the lower surface, and the plurality of side surfaces for unit length n. All are inscribed in an imaginary rectangular parallelepiped whose length of the first side is 50n on the surface located on the Miller index [001] plane, and where the length of the second side adjacent to the first side is 29n on the surface located on the Miller index [110] plane. an acousto-optic element formed to do so; and a transducer coupled to one of the plurality of sides and configured to radiate sound waves, wherein the plurality of sides form an angle between 16.5 and 17.5 degrees with respect to the Miller index plane, a first side with a length of 40n; A second side is bent at one side of the first side, extends between a surface located on the Miller index [001] plane of the virtual cuboid, and a surface located on the Miller index [110] plane, and has a length of 37n. ; and a third side that is bent and connected to the other side of the first side and has a length of 16n, wherein the transducer is coupled to one side of the first side and extends along the longitudinal direction of the first side. It can have a length of 14n or less.

According to the means for solving the problems of the present invention as discussed above, various effects including the following can be expected. However, the present invention does not require all of the following effects to be achieved.

One embodiment of the present invention can provide an acousto-optic variable filter that can detect light in the long-wavelength infrared band and can be used at low RF frequencies.

In addition, one embodiment of the present invention detects light in the long-wavelength infrared band using a mercury halide crystal, but can reduce the possibility of defects due to splitting of the mercury halide crystal and enables an easier manufacturing method. Filters can be provided.

Additionally, an embodiment of the present invention can provide a variable acousto-optic filter capable of detecting light in the long-wavelength infrared band with a wider viewing angle.

1 is a plan view illustrating an acousto-optic variable filter according to a first embodiment of the present invention.
Figure 2 is a plan view illustrating an acousto-optic variable filter according to a second embodiment of the present invention.
Figure 3 is a plan view illustrating an acousto-optic variable filter according to a third embodiment of the present invention.
Figure 4 is a plan view illustrating an acousto-optic variable filter according to a fourth embodiment of the present invention.
Figure 5 is a plan view illustrating an acousto-optic variable filter according to a fifth embodiment of the present invention.
Figure 6 is a plan view illustrating an acousto-optic variable filter according to a sixth embodiment of the present invention.
Figure 7 is a plan view illustrating an acousto-optic variable filter according to a seventh embodiment of the present invention.
Figure 8 is a plan view illustrating an acousto-optic variable filter according to an eighth embodiment of the present invention.
Figure 9 is a graph showing the acousto-optic characteristics of mercury halide crystals used in one embodiment of the present invention.

Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all transformations, equivalents, and substitutes included in the spirit and technical scope of the present invention. In describing the present invention, if it is determined that a detailed description of related known technologies may obscure the gist of the present invention, the detailed description will be omitted.

The terms used in this application are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Terms such as first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the description with reference to the accompanying drawings, identical or corresponding components will be assigned the same reference numbers regardless of the reference numerals, and duplicates thereof will be provided. Any necessary explanation will be omitted.

1 to 8 are plan views exemplarily showing variable acousto-optic filters 100 to 800 according to some embodiments of the present invention, and FIG. 9 shows acousto-optic characteristics of mercury halide crystals used in one embodiment of the present invention. This is a graph representing .

When a sound wave passes through a transparent medium, the sound wave periodically modulates the refractive index within the medium, and as a result, the light beam passing through the medium is diffracted into first and second diffracted light. For a given acousto-optic medium, the angle of diffraction is proportional to the frequency of the sound wave, while the frequency of the sound wave for generating diffraction is proportional to the wavelength of light. Therefore, the slower the speed of sound waves in a medium, the larger the diffraction angle of the first-order diffracted light of a light beam of a given wavelength.

The operation of acousto-optic devices generally blocks zero-order diffracted light (i.e., non-diffracted light) and utilizes first-order diffraction light, so the larger the first-order diffraction angle, the easier it is to use the acousto-optic device. To date, not many materials have been discovered that provide a large diffraction angle in the long-wave infrared (LWIR) band, but crystals of mercury halide exhibit acousto-optic properties at industrially usable levels in the long-wave infrared band, and acousto-optic filters are manufactured using this. It is possible. Mercury halide (Hg2

Figure 9 is a graph showing the acousto-optical characteristics of a mercury halide crystal used in an embodiment of the present invention. Specifically, a light beam with a wavelength of 10 μm is measured at various incident angles (on the vertical axis) for various acoustic angles (α) of 0 degrees to 24 degrees. indicates the frequency (MHz) of the sound wave (indicated on the horizontal axis) required to generate first-order diffracted light when passing through an acousto-optic filter made from mercury bromide (Hg2Br2) crystals. Here, the acoustic angle (α) represents the angle between the sound wave vector and the crystallographic axis z of the crystal, which is related to the speed of the sound wave passing through the crystal.

On the other hand, when an acousto-optic filter is manufactured from crystals such as mercury halide, it is extremely difficult to grow the crystals to the required size, so it may be required to grow the crystals to a required size or more and then process them to the required size. Methods for this may include grinding the crystals to the required size. Meanwhile, in the case of mercury halide crystals, a cleavage surface is formed along the Miller index [110] crystal direction, and therefore, it may be difficult to process the mercury halide crystals to the required size without cleavage.

Embodiments of the present invention make it possible to manufacture an acousto-optical filter in an easy and intuitive manner using mercury halide crystals such as mercury bromide.

Figure 1 is a plan view illustrating an acousto-optic variable filter 100 according to a first embodiment of the present invention.

The variable acousto-optic filter 100 according to the first embodiment of the present invention is formed of a mercury halide material and may include an acousto-optic element having a polyhedral shape and a transducer 10 coupled to one side of the acousto-optic element. . More specifically, the acousto-optical device may be formed by processing mercury bromide (Hg2Br2) crystals.

Figure 1 is a plan view of the variable acousto-optic filter 100. In Figure 1, the top surface of the polyhedral-shaped acousto-optic element is mainly expressed. In FIG. 1, the lower surface of the acousto-optical element is hidden behind the expressed upper surface, and the plurality of sides (110 to 150) of the polyhedral shape of the acousto-optical element are connected from each side of the upper surface shown in FIG. 1 to the corresponding side of the lower surface. You can.

In the acousto-optic element of the variable acousto-optic filter 100 according to the first embodiment of the present invention, the upper surface, lower surface, and plurality of side surfaces all have a first side length of 35 mm on the surface located on the Miller index plane and Miller index On the surface located on the [110] plane, the second side adjacent to the first side may be formed to be inscribed in a virtual rectangular parallelepiped with a length of 20 mm.

In FIG. 1, the acousto-optic variable filter 100 is depicted with this virtual rectangular parallelepiped, and the plan view of FIG. 1 shows only one rectangle corresponding to the upper surface of the rectangular parallelepiped. As described above, in Figure 1, the surface corresponding to the upper side of the rectangle is located on the Miller index [001] plane, and the surface corresponding to the side side of the rectangle is located on the Miller index [110] plane. In such a virtual rectangular parallelepiped, the distance between the upper and lower surfaces, that is, the height of each side (110 to 150) of the acousto-optic element of the variable acousto-optic filter 100, is not limited to a specific value.

In the first embodiment of the present invention, the plurality of sides of the acousto-optic device may include first to fifth sides 110 to 150. The first side 110 forms an angle of 10 degrees with respect to the Miller index [001] plane and may have a length of approximately 30 mm. The second side 120 is bent and connected to one side of the first side 110, is located on the Miller index [110] plane, and may have a length of approximately 6 mm. The third side 130 is bent and connected to one side of the second side 120, and extends between the surface located on the Miller index [001] plane and the surface located on the Miller index [110] plane of the above virtual rectangular parallelepiped. , can have a length of approximately 11 mm. The fourth side 140 is bent and connected to the other side of the first side 110, and may have a length of approximately 16 mm. The fifth side 150 extends between one side of the third side 130 and the other side of the fourth side 140, and may have a length of approximately 29 mm.

The transducer 10 may be configured to radiate sound waves by being coupled to the first side 110 of the acousto-optic element. The transducer 10 may have a length of approximately 8 mm or less and the first side 110 It can be combined on one side of . That is, the transducer 10 may have a length of 8 mm or less along the longitudinal direction of the first side 110.

The design dimensions of the variable acousto-optic filter 100 according to the first embodiment of the present invention shown in FIG. 1 are as shown in [Table 1] below.

Design dimensions of variable acousto-optic filter X size [001] [mm] 35 Y size [110] [mm] 20 transducer length [mm] 8 acoustic angle [Angle] 10 entrance surface [mm] 11 exit surface [mm] 16 Transducer side [mm] 30 center frequency [MHz] 15.86

Referring to FIG. 1, the first side 110 serves as the transducer surface, the third side 130 serves as the incident surface of the light beam, and the fourth side 140 serves as the emission surface of the diffracted light. When the transducer 10 coupled to the first side 110 radiates a sound wave with a center frequency of 15.86 MHz, the sound wave has a walk-off angle with respect to the normal direction of the first side 110, which is the transducer surface. The light beam that proceeds within the sound wave area 20 inclined by (ω) and flows into the third side 130, which is the incident surface, is diffracted by modulation of the sound wave and moves along the light beam area 30 to the fourth side, which is the exit surface. (140) and can be detected by a separate device.

If the first side 110 forms an angle of 10 degrees with respect to the Miller index [001] plane, the acoustic angle becomes 10 degrees. Looking at the curve in the graph of Figure 9 where the acoustic angle (α) is 10 degrees (near the 6th curve from the left), when the sound wave is radiated at a frequency of about 15.86 MHz, it has a relatively wide range (between 20 and 30 degrees) compared to other frequencies. ) It can be confirmed that light with a wavelength of 10 μm can be diffracted at the angle of incidence.

In the acousto-optic filter 100 according to the first embodiment of the present invention, the sound wave enters the first side 110 and propagates along the sound wave area 20 to reach the fifth side 150, and the light beam is transmitted through the third side 150. It enters the side 130, propagates along the light beam area 30, is diffracted by sound waves, and then radiates to the fourth side 140. In the embodiment shown in FIG. 1, when the light beam is incident on the third side 130, which is the incident surface, in a section of about 6 mm corresponding to the light beam area 30, the transducer 10 is activated and generates a frequency of about 15.86 MHz. When generating a sound wave, the light component with a wavelength of 10 μm included in the light beam may be emitted in a section of about 5 mm corresponding to the light beam area 30 of the fourth side 140, which is the emission surface.

If a sound wave also reaches the side where the diffracted light is emitted, the sound wave may act as interference to the diffracted light. However, in the acousto-optic filter 100 according to the first embodiment of the present invention, the side where the sound wave reaches is the side where the light beam is emitted. Separated from the surface, interference caused by sound waves can be minimized.

The method of manufacturing the acousto-optic filter 100 according to the first embodiment of the present invention includes preparing a mercury halide crystal, processing the mercury halide crystal into the acousto-optic element, and combining the transducer 10. It may include steps.

The step of preparing a mercury halide crystal is a process in which the length of the first side on the surface located on the Miller index [001] plane is 35 mm and the length of the second side adjacent to the first side on the surface located on the Miller index [110] plane is 20 mm. A step of preparing mercury halide crystals with a volume larger than a virtual rectangular parallelepiped may be included. For example, this involves growing a mercury bromide (Hg2Br2) crystal to a size large enough to contain the cuboid inside, with the side surfaces of the above cuboid aligned on the Miller index [001] plane and the Miller index [110] plane. It can also be accomplished through a process.

Processing the mercury halide crystals into an acousto-optic device may include polishing the mercury halide crystals so that the surfaces of the mercury halide crystals achieve the dimensions of the acousto-optic device described above.

The step of polishing each surface of the acousto-optic element is to place a mercury halide crystal on a surface located on the Miller index [001] plane, as shown in FIG. 1, with a first side length of 35 mm and located on the Miller index [110] plane. This may be performed after first processing the surface into a virtual rectangular parallelepiped shape where the second side adjacent to the first side has a length of 20 mm.

To form the first side 110, one surface of the rectangular parallelepiped located on the Miller index [001] plane is positioned at a position corresponding to approximately 5.5 mm from the lower left corner of the rectangle shown in FIG. 1. Can be polished at an angle of approximately 10 degrees.

To form the second side 120, the surface located on one side of the first side 110 and located on the Miller index [110] plane may be polished.

To form the third side 130, the surface between the surface located on the Miller index [001] plane and the surface located on the Miller index [110] plane of the virtual cuboid may be polished.

To form the fourth side 140, the surface between the other side of the first side 110 and the surface located on the Miller index [110] plane may be polished.

To form the fifth side 150, the surface between one side of the third side 130 and the other side of the fourth side 140 may be polished.

If necessary, the top and bottom surfaces of the acousto-optic element can also be polished flat.

In the above polishing step, the first side 110 forms approximately 30 mm, the second side 120 forms approximately 6 mm, the third side 130 forms approximately 11 mm, and the fourth side 140 forms approximately 11 mm. It can progress until it forms 16 mm, and the fifth side 150 forms approximately 29 mm.

The step of combining the transducer 10 can be performed by combining the transducer 10, which has a length of approximately 8 mm or less and is configured to emit sound waves with a center frequency of about 15.86 MHz, to one side of the first side 110. . If necessary, a sound absorbing body 50 (see FIG. 2), which will be described later, may be further coupled to the acousto-optical element of the acousto-optical filter 100 according to the first embodiment of the present invention.

In the acousto-optic filter (100), the angle is generally more important than dimensions such as length, but when processing an acousto-optic element, it can be very difficult to polish the surface by focusing on the angle, and therefore, the acousto-optic filter (100 ) The sides (120 to 150) other than the first side (110) related to the acoustic angle (α), which directly affects the performance of the acousto-optics, are polished until the length, not the angle, reaches a specific value. Devices can be processed. This provides the effect of facilitating the production of the acousto-optic device and the acousto-optic filter 100.

Above, the specific dimensions of the acousto-optic filter 100 according to the first embodiment of the present invention are expressed in millimeters, which corresponds to expressing each dimension as a ratio to the unit length n of 1 mm. However, when the acousto-optic filter 100 is manufactured with dimensions proportional to the above dimensions, that is, the unit length n is set to an arbitrary length greater than 0 and each dimension is set at the same ratio to n. It may be said to fall within the scope of the invention.

The acousto-optic filter 100 according to the first embodiment of the present invention makes it possible to detect optical components in the long-wavelength infrared band and provides the advantage of being able to be used as a sound wave of a very low RF frequency of about 16 MHz or less.

A large amount of polishing is not required to manufacture the acousto-optic element of the acousto-optic filter 100 according to the first embodiment of the present invention, and when manufacturing the acousto-optical element, only the sides need to be polished mainly along the length, thereby providing a high-performance acousto-optic filter. (100) has the advantage of being very easy to produce. In particular, since mercury halide crystals can be polished at a low acoustic angle, the possibility of splitting occurring on the transducer surface and other areas can be reduced.

Figure 2 is a plan view illustrating an acousto-optic variable filter 200 according to a second embodiment of the present invention. The variable acousto-optic filter 200 according to the second embodiment of the present invention has something in common with the variable acousto-optic filter 100 according to the first embodiment, and the second embodiment will be described below focusing on the differences from the first embodiment. Let me explain an example.

The variable acousto-optic filter 200 according to the second embodiment of the present invention is formed of a mercury halide material and includes an acousto-optic element having a polyhedral shape, a transducer 10 coupled to one side of the acousto-optic element, and an acousto-optic element. It may include a sound absorbing body 50 coupled to the other side. More specifically, the acousto-optical device may be formed by processing mercury bromide (Hg2Br2) crystals.

Figure 2 is a plan view of the variable acousto-optic filter 200, and in Figure 2, the top surface of the polyhedral-shaped acousto-optic element is mainly expressed. In FIG. 2, the lower surface of the acousto-optical element is hidden behind the expressed upper surface, and the plurality of sides (210 to 260) of the polyhedral shape of the acousto-optical element are connected from each side of the upper surface shown in FIG. 2 to the corresponding side of the lower surface. You can.

In the acousto-optical element of the variable acousto-optic filter 200 according to the second embodiment of the present invention, the upper surface, lower surface, and plurality of side surfaces all have a first side length of 35 mm on the surface located on the Miller index plane and Miller index On the surface located on the [110] plane, the second side adjacent to the first side may be formed to be inscribed in a virtual rectangular parallelepiped with a length of 20 mm.

In FIG. 2, the acousto-optic variable filter 200 is depicted with this virtual rectangular parallelepiped, and the top view of FIG. 2 shows only one rectangle corresponding to the upper surface of the rectangular parallelepiped. As described above, in FIG. 2, the surface corresponding to the upper side of the rectangle is located on the Miller index [001] plane, and the surface corresponding to the side side of the rectangle is located on the Miller index [110] plane. In such a virtual rectangular parallelepiped, the distance between the upper and lower surfaces, that is, the height of each side (210 to 260) of the acousto-optic element of the variable acousto-optic filter 200, is not limited to a specific value.

In a second embodiment of the present invention, the plurality of sides of the acousto-optic device may include first to sixth sides 210 to 260. The first side 210 forms an angle of 10 degrees with respect to the Miller index [001] plane and may have a length of approximately 30 mm. The second side 220 is bent and connected to one side of the first side 210, is located on the Miller index [110] plane, and may have a length of approximately 6 mm. The third side 230 is bent and connected to one side of the second side 220, and extends between the surface located on the Miller index [001] plane and the surface located on the Miller index [110] plane of the above virtual rectangular parallelepiped. , can have a length of approximately 11 mm. The fourth side 240 is bent and connected to the other side of the first side 210, and may have a length of approximately 16 mm. The fifth side 250 is bent and connected to the other side of the fourth side 240, is located on the Miller index [110] plane, and may have a length of approximately 5 mm. The sixth side 260 extends between one side of the third side 230 and the other side of the fifth side 250, and may be located in the Miller index plane.

The transducer 10 may be configured to radiate sound waves by being coupled to the first side 110 of the acousto-optic element. The transducer 10 may have a length of approximately 8 mm or less and the first side 110 It can be combined on one side of . That is, the transducer 10 may have a length of 8 mm or less along the longitudinal direction of the first side 110.

Meanwhile, the sound absorbing body 50 may be configured to absorb sound waves, and may be mounted in a necessary position among the areas formed by the fourth side 240, the fifth side 250, and the sixth side 260. When the sound absorbing body 50 is mounted on the fourth side 240, it may be placed to avoid the light beam area 30. Preferably, the sound absorbing body 50 may be mounted on the fifth side 250.

As in the first embodiment, the first side 210 forms an angle of 10 degrees with respect to the Miller index [001] plane, so that the acoustic angle is 10 degrees. Looking at the curve in the graph of Figure 9 where the acoustic angle (α) is 10 degrees (near the 6th curve from the left), when the sound wave is radiated at a frequency of about 15.86 MHz, it has a relatively wide range (between 20 and 30 degrees) compared to other frequencies. ) It can be confirmed that light with a wavelength of 10 μm can be diffracted at the angle of incidence.

In the acousto-optic filter 200 according to the second embodiment of the present invention, the sound wave enters the first side 210 and propagates along the sound wave area 20 to reach the fifth side 250, and the light beam is transmitted through the third side 250. It enters the side 230, propagates along the light beam area 30, is diffracted by sound waves, and then radiates to the fourth side 240. In the embodiment shown in FIG. 2, when the light beam is incident on the third side 130, which is the incident surface, in a section of about 6 mm corresponding to the light beam area 30, the transducer 10 is activated and generates a frequency of about 15.86 MHz. When generating a sound wave, the light component with a wavelength of 10 μm included in the light beam may be emitted in a section of about 5 mm corresponding to the light beam area 30 of the fourth side 240, which is the emission surface.

When a sound wave reaches the boundary between different media (in this embodiment, the side of the acousto-optic element, which is the boundary between the crystal of the acousto-optic element and air), there is a possibility that the sound wave will be reflected, and the reflected component of the sound wave is reflected in the diffracted light. may act as an interference. In the acousto-optic filter 200 according to the second embodiment of the present invention, the fifth side 250, which is the side where the sound waves radiating from the 8 mm transducer 10 arrive, is the fourth side corresponding to the exit surface of the light beam ( 240), but in order to remove reflection components that may occur due to tolerances, etc. and minimize interference, sound waves can be absorbed in a part of the area formed by the fifth side 250 and the fourth side 240. A sound absorbing body 50 may be installed.

The method of manufacturing the acousto-optic filter 200 according to the second embodiment of the present invention includes preparing a mercury halide crystal, processing the mercury halide crystal into the acousto-optic element, and transducer 10 and sound absorption. It may include the step of combining the sieve 50.

The step of preparing a mercury halide crystal is a process in which the length of the first side on the surface located on the Miller index [001] plane is 35 mm and the length of the second side adjacent to the first side on the surface located on the Miller index [110] plane is 20 mm. A step of preparing mercury halide crystals with a volume larger than a virtual rectangular parallelepiped may be included. For example, this involves growing a mercury bromide (Hg2Br2) crystal to a size large enough to contain the cuboid inside, with the side surfaces of the above cuboid aligned on the Miller index [001] plane and the Miller index [110] plane. It can also be accomplished through a process.

Processing the mercury halide crystals into an acousto-optic device may include polishing the mercury halide crystals so that the surfaces of the mercury halide crystals achieve the dimensions of the acousto-optic device described above.

The step of polishing each surface of the acousto-optic element is to place a mercury halide crystal on a surface located on the Miller index [001] plane, as shown in FIG. 2, with a first side length of 35 mm and located on the Miller index [110] plane. It may include first processing the surface into a virtual rectangular parallelepiped shape where the second side adjacent to the first side has a length of 20 mm.

Then, to form the first side 210, one surface of the cuboid located on the Miller index [001] plane is bent at an angle of approximately 10 degrees at a position corresponding to approximately 5.5 mm from the lower left corner of the rectangle shown in FIG. 2. It can be polished.

In order to form the third side 230, it is located on the Miller index plane of the virtual rectangular parallelepiped, leaving a length of 6 mm corresponding to the length of the second side 220 from one side of the first side 210. The surface between the surface and the surface located on the Miller index [110] plane can be polished.

To form the fourth side 240, the other side of the first side 210 and the Miller index are separated, leaving a length of 5 mm corresponding to the length of the fifth side 250 on the surface located on the Miller index [110] plane. The surfaces between surfaces located on the [110] plane can be polished.

The second side 220, the fifth side 250, and the sixth side 260 are part of the previously processed rectangular parallelepiped and do not require separate processing.

In the above polishing step, the first side 210 forms approximately 30 mm, the second side 220 forms approximately 6 mm, the third side 230 forms approximately 11 mm, and the fourth side 240 forms approximately 11 mm. It can progress until it forms 16 mm, and the fifth side 250 forms approximately 5 mm.

The step of combining the transducer 10 and the sound absorbing body 50 is to place the transducer 10, which has a length of approximately 8 mm or less and is configured to radiate a sound wave with a center frequency of about 15.86 MHz, on one side of the first side 210. This is performed by combining the sound absorbing body 50, which has a length of approximately 5 mm and is configured to absorb sound waves, at a specific position among the areas formed by the fourth side 240, the fifth side 250, and the sixth side 260. It can be.

Above, the specific dimensions of the acousto-optic filter 200 according to the second embodiment of the present invention are expressed in millimeters, which corresponds to expressing each dimension as a ratio to the unit length n of 1 mm. However, when the acousto-optic filter 200 is manufactured with dimensions proportional to the above dimensions, that is, the unit length n is set to an arbitrary length greater than 0 and each dimension is set at the same ratio to n. It may be said to fall within the scope of the invention.

The acousto-optic filter 200 according to the second embodiment of the present invention enables detection of optical components in the long-wave infrared band and provides the advantage of being usable with sound waves of very low RF frequencies of about 16 MHz or less.

A large amount of polishing is not required to manufacture the acousto-optic element of the acousto-optic filter 200 according to the second embodiment of the present invention, and when manufacturing the acousto-optical element, only the sides need to be polished mainly along the length, thereby providing a high-performance acousto-optic filter. (200) has the advantage of being very easy to produce.

In particular, in the acousto-optic filter 200 according to the second embodiment of the present invention, mercury halide crystals can be polished at a low acoustic angle, and the amount of polishing of the acousto-optic element is reduced by the acousto-optic filter 100 according to the first embodiment. ), making it easier to manufacture and less likely to cause splitting.

Figure 3 is a plan view illustrating an acousto-optic variable filter 300 according to a third embodiment of the present invention.

The variable acousto-optic filter 300 according to the third embodiment of the present invention is formed of a mercury halide material and may include an acousto-optic element having a polyhedral shape and a transducer 10 coupled to one side of the acousto-optic element. . More specifically, the acousto-optical device may be formed by processing mercury bromide (Hg2Br2) crystals.

Figure 3 is a plan view of the variable acousto-optic filter 300, and in Figure 3, the top surface of the polyhedral-shaped acousto-optic element is mainly expressed. In FIG. 3, the lower surface of the acousto-optical element is hidden behind the expressed upper surface, and the plurality of sides (310 to 340) of the polyhedral shape of the acousto-optical element are connected from each side of the upper surface shown in FIG. 3 to the corresponding side of the lower surface. You can.

In the acousto-optic element of the variable acousto-optic filter 300 according to the third embodiment of the present invention, the upper surface, lower surface, and plural side surfaces all have a first side length of 45 mm on the surface located on the Miller index plane and Miller index On the surface located on the [110] plane, the second side adjacent to the first side may be formed to be inscribed in a virtual rectangular parallelepiped whose length is 23 mm.

In FIG. 3, the variable acousto-optic filter 300 is depicted with this virtual rectangular parallelepiped, and only one rectangle corresponding to the upper surface of the rectangular parallelepiped is shown in the plan view of FIG. 3. As described above, in FIG. 3, the surface corresponding to the upper side of the rectangle is located on the Miller index [001] plane, and the surface corresponding to the side side of the rectangle is located on the Miller index [110] plane. In such a virtual rectangular parallelepiped, the distance between the upper and lower surfaces, that is, the height of each side (310 to 340) of the acousto-optic element of the variable acousto-optic filter 300, is not limited to a specific value.

In a third embodiment of the present invention, the plurality of sides of the acousto-optic device may include first to fourth sides 310 to 340. The first side 310 forms an angle of 10 degrees with respect to the Miller index [001] plane and may have a length of approximately 40 mm. The second side 320 is bent and connected to one side of the first side 310, and extends between the surface located on the Miller index [001] plane and the surface located on the Miller index [110] plane of the above virtual rectangular parallelepiped. , may have a length of approximately 20 mm. The third side 330 is bent and connected to the other side of the first side 310, and may have a length of approximately 16 mm. The fourth side 340 extends between one side of the second side 320 and the other side of the third side 330, and may have a length of approximately 35 mm.

The transducer 10 may be configured to radiate sound waves by being coupled to the first side 310 of the acousto-optic element. The transducer 10 may have a length of approximately 14 mm or less and the first side 310 It can be combined on one side of . That is, the transducer 10 may have a length of 14 mm or less along the longitudinal direction of the first side 310.

The design dimensions of the acousto-optic variable filter 300 according to the third embodiment of the present invention shown in FIG. 3 are as shown in [Table 2] below.

Design dimensions of variable acousto-optic filter X size [001] [mm] 45 Y size [110] [mm] 23 transducer length [mm] 14 acoustic angle [Angle] 10 entrance surface [mm] 20 exit surface [mm] 16 Transducer side [mm] 40 center frequency [MHz] 15.86

Referring to FIG. 3, the first side 310 becomes the transducer surface, the second side 320 becomes the incident surface of the light beam, and the third side 330 becomes the exit surface of the diffracted light. When the transducer 10 coupled to the first side 310 radiates a sound wave with a center frequency of 15.86 MHz, the sound wave is inclined by the walk-off angle (ω) with respect to the normal direction of the first side 310, which is the transducer surface. The light beam that travels within the sound wave area 20 and flows into the second side 320, which is the incident surface, is diffracted by modulation of the sound wave and radiates along the light beam area 30 to the third side 330, which is the exit surface. Can be detected by a separate device.

When the first side 310 forms an angle of 10 degrees with respect to the Miller index [001] plane, the acoustic angle becomes 10 degrees. Looking at the curve in the graph of Figure 9 where the acoustic angle (α) is 10 degrees (near the 6th curve from the left), when the sound wave is radiated at a frequency of about 15.86 MHz, it has a relatively wide range (between 20 and 30 degrees) compared to other frequencies. ) It can be confirmed that light with a wavelength of 10 μm can be diffracted at the angle of incidence.

In the acousto-optic filter 300 according to the third embodiment of the present invention, the sound wave enters the first side 310 and propagates along the sound wave area 20 to reach the fourth side 340, and the light beam is transmitted through the second side 340. It enters the side 320, propagates along the light beam area 30, is diffracted by sound waves, and then radiates to the third side 330. In the embodiment shown in FIG. 3, when the light beam is incident on the second side 320, which is the incident surface, in a section of about 7 mm corresponding to the light beam area 30, the transducer 10 is activated and operates at a frequency of about 15.86 MHz. When generating a sound wave, the light component with a wavelength of 10 μm included in the light beam may be emitted in a section of about 6 mm corresponding to the light beam area 30 of the third side 330, which is the emission surface.

If a sound wave also reaches the side where the diffracted light is emitted, the sound wave may act as interference to the diffracted light. However, in the acousto-optic filter 300 according to the third embodiment of the present invention, the side where the sound wave reaches is the side where the light beam is emitted. Separated from the surface, interference caused by sound waves can be minimized.

The method of manufacturing the acousto-optic filter 300 according to the third embodiment of the present invention includes preparing a mercury halide crystal, processing the mercury halide crystal into the acousto-optic element, and combining the transducer 10. It may include steps.

The step of preparing a mercury halide crystal is a process in which the length of the first side on the surface located on the Miller index [001] plane is 45 mm, and the length of the second side adjacent to the first side on the surface located on the Miller index [110] plane is 23 mm. A step of preparing mercury halide crystals with a volume larger than a virtual rectangular parallelepiped may be included. For example, this involves growing a mercury bromide (Hg2Br2) crystal to a size large enough to contain the cuboid inside, with the side surfaces of the above cuboid aligned on the Miller index [001] plane and the Miller index [110] plane. It can also be accomplished through a process.

Processing the mercury halide crystals into an acousto-optic device may include polishing the mercury halide crystals so that the surfaces of the mercury halide crystals achieve the dimensions of the acousto-optic device described above.

The step of polishing each surface of the acousto-optic element is to place a mercury halide crystal on a surface located on the Miller index [001] plane, as shown in FIG. 3, with a first side length of 45 mm and located on the Miller index [110] plane. This may be performed after first processing the surface into a virtual rectangular parallelepiped shape where the second side adjacent to the first side has a length of 23 mm.

To form the first side 310, one surface of the cuboid located on the Miller index [001] plane is ground at an angle of approximately 10 degrees at a position corresponding to approximately 6.5 mm from the lower left corner of the rectangle shown in FIG. 3. can do.

To form the second side 320, the surface between one side of the first side 310 and the surface located on the Miller index [001] plane may be polished.

To form the third side 330, the surface between the other side of the first side 310 and the surface located on the Miller index [110] plane may be polished.

To form the fourth side 340, the surface between one side of the second side 320 and the other side of the third side 330 may be polished.

If necessary, the top and bottom surfaces of the acousto-optic element can also be polished flat.

In the above polishing step, the first side 310 forms approximately 40 mm, the second side 320 forms approximately 20 mm, the third side 330 forms approximately 16 mm, and the fourth side 340 forms approximately 16 mm. It can progress until 35mm is achieved.

The step of combining the transducer 10 can be performed by combining the transducer 10, which has a length of approximately 14 mm or less and is configured to emit sound waves with a center frequency of approximately 15.86 MHz, to one side of the first side 310. . If necessary, a sound absorbing body 50 may be further coupled to the acousto-optical element of the acousto-optical filter 300 according to the third embodiment of the present invention.

Above, the specific dimensions of the acousto-optic filter 300 according to the third embodiment of the present invention are expressed in millimeters, which corresponds to expressing each dimension as a ratio to the unit length n of 1 mm. However, when the acousto-optic filter 300 is manufactured with dimensions proportional to the above dimensions, that is, the unit length n is set to an arbitrary length greater than 0 and each dimension is set at the same ratio to n. It may be said to fall within the scope of the invention.

The acousto-optic filter 300 according to the third embodiment of the present invention enables detection of optical components in the long-wavelength infrared band and provides the advantage of being usable with very low frequency sound waves of about 16 MHz or less.

A large amount of polishing is not required to manufacture the acousto-optic element of the acousto-optic filter 300 according to the third embodiment of the present invention, and when manufacturing the acousto-optical element, only the sides need to be polished mainly along the length, thereby providing a high-performance acousto-optic filter. There is an advantage that (300) can be manufactured very easily. In particular, since mercury halide crystals can be polished at a low acoustic angle, the possibility of splitting occurring on the transducer surface and other areas can be reduced.

Figure 4 is a plan view illustrating an acousto-optic variable filter 400 according to a fourth embodiment of the present invention. The variable acousto-optic filter 400 according to the fourth embodiment of the present invention has something in common with the variable acousto-optic filter 300 according to the third embodiment, and the fourth embodiment will be described below focusing on the differences from the third embodiment. Let me explain an example.

The variable acousto-optic filter 400 according to the fourth embodiment of the present invention is formed of a mercury halide material and may include an acousto-optic element having a polyhedral shape and a transducer 10 coupled to one side of the acousto-optic element. . More specifically, the acousto-optical device may be formed by processing mercury bromide (Hg2Br2) crystals.

Figure 4 is a plan view of the variable acousto-optic filter 400, and in Figure 4, the top surface of the polyhedral-shaped acousto-optic element is mainly expressed. In FIG. 4, the lower surface of the acousto-optic element is hidden behind the expressed upper surface, and the plurality of sides (410 to 460) of the polyhedral shape of the acousto-optical element are connected from each side of the upper surface shown in FIG. 4 to the corresponding side of the lower surface. You can.

In the acousto-optic element of the variable acousto-optic filter 400 according to the fourth embodiment of the present invention, the upper surface, lower surface, and plural side surfaces all have a first side length of 45 mm on the surface located on the Miller index plane and Miller index On the surface located on the [110] plane, the second side adjacent to the first side may be formed to be inscribed in a virtual rectangular parallelepiped whose length is 23 mm.

In FIG. 4, the acousto-optic variable filter 400 is depicted with this virtual rectangular parallelepiped, and the top view of FIG. 4 shows only one rectangle corresponding to the upper surface of the rectangular parallelepiped. As described above, in FIG. 4, the surface corresponding to the upper side of the rectangle is located on the Miller index [001] plane, and the surface corresponding to the side side of the rectangle is located on the Miller index [110] plane. In such a virtual rectangular parallelepiped, the distance between the upper and lower surfaces, that is, the height of each side (410 to 460) of the acousto-optic element of the variable acousto-optic filter 400, is not limited to a specific value.

In the fourth embodiment of the present invention, the plurality of sides of the acousto-optic device may include first to sixth sides 410 to 460. The first side 410 forms an angle of 10 degrees with respect to the Miller index [001] plane and may have a length of approximately 40 mm. The second side 420 is bent and connected to one side of the first side 410, and extends between the surface located on the Miller index [001] plane and the surface located on the Miller index [110] plane of the above virtual rectangular parallelepiped. , may have a length of approximately 20 mm. The third side 430 extends between the other side of the first side 410 and a surface located on the Miller index [001] plane of the above virtual rectangular parallelepiped, and may have a length of approximately 16 mm. The fourth side 440 is bent and connected to the other side of the third side 410, is located on the Miller index [110] plane, and may have a length of approximately 2 mm. The fifth side 450 is bent and connected to the other side of the fourth side 440, and extends between the surface located on the Miller index [001] plane and the surface located on the Miller index [110] plane of the above virtual rectangular parallelepiped. , may have a length of approximately 26 mm. The sixth side 460 extends between one side of the second side 420 and the other side of the fifth side 450, is located in the Miller index plane, and may have a length of approximately 8 mm.

The transducer 10 may be configured to radiate sound waves by being coupled to the first side 410 of the acousto-optic element. The transducer 10 may have a length of approximately 14 mm or less and the first side 410 It can be combined on one side of . That is, the transducer 10 may have a length of 14 mm or less along the longitudinal direction of the first side 410.

As in the third embodiment, the first side 410 forms an angle of 10 degrees with respect to the Miller index [001] plane, so the acoustic angle is 10 degrees. Looking at the curve in the graph of Figure 9 where the acoustic angle (α) is 10 degrees (near the 6th curve from the left), when the sound wave is radiated at a frequency of about 15.86 MHz, it has a relatively wide range (between 20 and 30 degrees) compared to other frequencies. ) It can be confirmed that light with a wavelength of 10 μm can be diffracted at the angle of incidence.

In the acousto-optic filter 400 according to the fourth embodiment of the present invention, the sound wave enters the first side 410 and propagates along the sound wave area 20 to reach the fifth side 450, and the light beam is transmitted through the second side 450. It enters the side 430, propagates along the light beam area 30, is diffracted by sound waves, and then radiates to the third side 430. In the embodiment shown in FIG. 4, when the light beam is incident on the second side 420, which is the incident surface, in a section of about 7 mm corresponding to the light beam area 30, the transducer 10 is activated and operates at a frequency of about 15.86 MHz. When generating a sound wave, the light component with a wavelength of 10 μm included in the light beam may be emitted in a section of about 6 mm corresponding to the light beam area 30 of the third side 430, which is the emission surface.

Compared to the acousto-optic filter 300 according to the third embodiment of the present invention, in the acousto-optic filter 400 according to the fourth embodiment of the present invention, the sound wave area 20 has one side (i.e., the fifth side ( 450)), it prevents reflection of sound waves and reduces the amount of polishing in that area, making it easier to manufacture acousto-optic devices. For reference, if the fifth side 450 of the acousto-optic element of the acousto-optic filter 400 according to the fourth embodiment of the present invention is further polished, the acousto-optic element of the acousto-optic filter 300 according to the third embodiment of the present invention The same shape as can be obtained. The acousto-optic filter 400 according to the fourth embodiment of the present invention is a sound absorbing body mounted at a specific position among the areas formed by the third side 430, fourth side 440, and fifth side 450 as needed. It may also include more.

The method of manufacturing the acousto-optic filter 400 according to the fourth embodiment of the present invention includes preparing a mercury halide crystal, processing the mercury halide crystal into the acousto-optic element, and combining the transducer 10. It may include steps.

The step of preparing a mercury halide crystal is a process in which the length of the first side on the surface located on the Miller index [001] plane is 45 mm, and the length of the second side adjacent to the first side on the surface located on the Miller index [110] plane is 23 mm. A step of preparing mercury halide crystals with a volume larger than a virtual rectangular parallelepiped may be included. For example, this involves growing a mercury bromide (Hg2Br2) crystal to a size large enough to contain the cuboid inside, with the side surfaces of the above cuboid aligned on the Miller index [001] plane and the Miller index [110] plane. It can also be accomplished through a process.

Processing the mercury halide crystals into an acousto-optic device may include polishing the mercury halide crystals so that the surfaces of the mercury halide crystals achieve the dimensions of the acousto-optic device described above.

The step of polishing each surface of the acousto-optic element is to place a mercury halide crystal on a surface located on the Miller index [001] plane, as shown in FIG. 4, with a first side length of 45 mm and located on the Miller index [110] plane. It may include first processing the surface into the shape of a virtual rectangular parallelepiped with a second side adjacent to the first side having a length of 23 mm.

Then, to form the first side 410, one surface of the cuboid located on the Miller index [001] plane is positioned at an angle of approximately 10 degrees at a position corresponding to approximately 6.5 mm from the lower left corner of the rectangle shown in FIG. 4. It can be polished.

To form the second side 420, the surface between one side of the first side 410 and the surface located on the Miller index [001] plane may be polished.

To form the third side 430, the surface between the other side of the first side 410 and the surface located on the Miller index [110] plane may be polished.

To form the fifth side 450, a length of 8 mm corresponding to the length of the sixth side 460 is left on the surface located on the Miller index [001] plane, and a length of 8 mm is left on the surface located on the Miller index [110] plane. 4 The surface between the surface located on the Miller index [001] plane and the surface located on the Miller index [110] plane can be polished while leaving a length of 2 mm corresponding to the length of the side 440.

The fourth side 440 and the sixth side 460 are part of the previously processed rectangular parallelepiped and do not require separate processing.

In the above polishing step, the first side 410 forms approximately 40 mm, the second side 420 forms approximately 20 mm, the third side 430 forms approximately 16 mm, and the fourth side 440 forms approximately 16 mm. It may progress until it forms 2 mm, the fifth side 450 forms approximately 26 mm, and the sixth side 460 forms approximately 8 mm.

The step of combining the transducer 10 can be performed by combining the transducer 10, which has a length of approximately 14 mm or less and is configured to emit sound waves with a center frequency of approximately 15.86 MHz, to one side of the first side 410. . If necessary, a sound absorbing body 50 may be further coupled to the acousto-optical element of the acousto-optical filter 400 according to the fourth embodiment of the present invention.

Above, the specific dimensions of the acousto-optic filter 400 according to the fourth embodiment of the present invention are expressed in millimeters, which corresponds to expressing each dimension as a ratio to the unit length n of 1 mm. However, in the case where the acousto-optic filter 400 is manufactured with dimensions proportional to the above dimensions, that is, the unit length n is set to an arbitrary length greater than 0 and each dimension is set at the same ratio to n, this is also the case. It may be said to fall within the scope of the invention.

The acousto-optic filter 400 according to the fourth embodiment of the present invention enables detection of optical components in the long-wavelength infrared band and provides the advantage of being usable with very low frequency sound waves of about 16 MHz or less.

A large amount of polishing is not required to manufacture the acousto-optic element of the acousto-optic filter 400 according to the fourth embodiment of the present invention, and when manufacturing the acousto-optical element, only the sides need to be polished mainly along the length, thereby providing a high-performance acousto-optic filter. There is an advantage that (400) can be produced very easily.

In particular, in the acousto-optic filter 400 according to the fourth embodiment of the present invention, mercury halide crystals can be polished at a low acoustic angle, and the amount of polishing of the acousto-optic element is reduced by the acousto-optic filter 300 according to the third embodiment of the present invention. ), making it easier to manufacture and less likely to cause splitting.

Figure 5 is a plan view illustrating an acousto-optic variable filter 500 according to a fifth embodiment of the present invention.

The variable acousto-optic filter 500 according to the fifth embodiment of the present invention is formed of a mercury halide material and includes an acousto-optic element having a polyhedral shape and a transducer 10 coupled to one side of the acousto-optic element. . More specifically, the acousto-optical device may be formed by processing mercury bromide (Hg2Br2) crystals.

Figure 5 is a plan view of the variable acousto-optic filter 500, and in Figure 5, the top surface of the polyhedral-shaped acousto-optic element is mainly expressed. In FIG. 5, the lower surface of the acousto-optical element is hidden behind the expressed upper surface, and the plurality of sides (510 to 560) of the polyhedral shape of the acousto-optical element are connected from each side of the upper surface shown in FIG. 5 to the corresponding side of the lower surface. You can.

In the acousto-optic element of the variable acousto-optic filter 500 according to the fifth embodiment of the present invention, the upper surface, lower surface, and plural side surfaces all have a first side length of 35 mm on the surface located on the Miller index plane and Miller index On the surface located on the [110] plane, the second side adjacent to the first side may be formed to be inscribed in a virtual rectangular parallelepiped whose length is 21 mm.

In FIG. 5, the acousto-optic variable filter 500 is depicted with this virtual rectangular parallelepiped, and only one rectangle corresponding to the upper surface of the rectangular parallelepiped is shown in the plan view of FIG. 5. As described above, in Figure 5, the surface corresponding to the upper side of the rectangle is located on the Miller index [001] plane, and the surface corresponding to the side side of the rectangle is located on the Miller index [110] plane. In such a virtual rectangular parallelepiped, the distance between the upper and lower surfaces, that is, the height of each side (510 to 560) of the acousto-optic element of the variable acousto-optic filter 500, is not limited to a specific value.

In the fifth embodiment of the present invention, the plurality of sides of the acousto-optic device may include first to sixth sides 510 to 560. The first side 510 may form an angle between approximately 16.5 and 17.5 degrees with respect to the Miller index [001] plane and may have a length of approximately 24 mm. The second side 520 is bent and connected to one side of the first side 510, is located on the Miller index plane of the above virtual rectangular parallelepiped, and may have a length of approximately 4 mm. The third side 530 is bent and connected to one side of the second side 520, and extends between the surface located on the Miller index [001] plane and the surface located on the Miller index [110] plane of the above virtual rectangular parallelepiped. , may have a length of approximately 20 mm. The fourth side 540 is bent and connected to the other side of the first side 510, and may have a length of approximately 16 mm. The fifth side 550 is bent and connected to one side of the third side 530, is located on the Miller index [001] plane, and may have a length of approximately 8 mm. The sixth side 560 extends between one side of the fifth side 530 and the other side of the fourth side 540, and may have a length of approximately 13 mm.

The transducer 10 may be configured to radiate sound waves by being coupled to the first side 510 of the acousto-optic element. The transducer 10 may have a length of approximately 8 mm or less and the first side 510 It can be combined on one side of . That is, the transducer 10 may have a length of 8 mm or less along the longitudinal direction of the first side 510.

The design dimensions of the variable acousto-optic filter 500 according to the fifth embodiment of the present invention shown in FIG. 5 are as shown in [Table 3] below.

Design dimensions of variable acousto-optic filter X size [001] [mm] 35 Y size [110] [mm] 21 transducer length [mm] 8 acoustic angle [Angle] 16.5~17.5 entrance surface [mm] 20 exit surface [mm] 16 Transducer side [mm] 24 center frequency [MHz] less than 30

Referring to FIG. 5, the first side 510 becomes the transducer surface, the third side 530 becomes the incident surface of the light beam, and the fourth side 540 becomes the exit surface of the diffracted light. When the transducer 10 coupled to the first side 510 radiates a sound wave with a center frequency of less than 30 MHz, the sound wave is inclined by the walk-off angle (ω) with respect to the normal direction of the first side 510, which is the transducer surface. The light beam that proceeds within the sound wave area 20 and flows into the third side 130, which is the incident surface, is diffracted by modulation of the sound wave and radiates along the light beam area 30 to the fourth side 540, which is the exit surface. Can be detected by a separate device.

When the first side 510 forms a specific angle between 16.5 and 17.5 degrees with respect to the Miller index [001] plane, the angle becomes the acoustic angle. In the graph of Figure 9, looking at the curve with an acoustic angle (α) of 16 degrees and the curve with 18 degrees (the 9th and 10th curves from the left), it can be seen that the curve extends almost vertically in the corresponding part. there is. In other words, in this part, when sound waves are radiated at a specific frequency of less than 30 MHz, light with a wavelength of 10 μm can be diffracted in a very wide range of incident angles (more than 30 degrees).

In the acousto-optic filter 500 according to the fifth embodiment of the present invention, the sound wave enters the first side 510 and propagates along the sound wave area 20 to reach the sixth side 560, and the light beam is transmitted through the third side 560. It enters the side 530, propagates along the light beam area 30, is diffracted by sound waves, and then radiates to the fourth side 540. In the embodiment shown in FIG. 5, when the light beam is incident on the third side 530, which is the incident surface, in a section of about 6 mm corresponding to the light beam area 30, the transducer 10 is activated to transmit a specific signal below about 30 MHz. When a sound wave is generated at a frequency, the light component with a wavelength of 10 μm included in the light beam may be emitted in a section of about 5 mm corresponding to the light beam area 30 of the fourth side 540, which is the emission surface.

If a sound wave also reaches the side where the diffracted light is emitted, the sound wave may act as interference to the diffracted light. However, in the acousto-optic filter 500 according to the fifth embodiment of the present invention, the side where the sound wave reaches is the side where the light beam is emitted. Separated from the surface, interference caused by sound waves can be minimized.

The method of manufacturing the acousto-optic filter 500 according to the fifth embodiment of the present invention includes preparing a mercury halide crystal, processing the mercury halide crystal into the acousto-optic element, and combining the transducer 10. It may include steps.

The step of preparing a mercury halide crystal is a process in which the length of the first side on the surface located on the Miller index [001] plane is 35 mm and the length of the second side adjacent to the first side on the surface located on the Miller index [110] plane is 21 mm. A step of preparing mercury halide crystals with a volume larger than a virtual rectangular parallelepiped may be included. For example, this involves growing a mercury bromide (Hg2Br2) crystal to a size large enough to contain the cuboid inside, with the side surfaces of the above cuboid aligned on the Miller index [001] plane and the Miller index [110] plane. It can also be accomplished through a process.

Processing the mercury halide crystals into an acousto-optic device may include polishing the mercury halide crystals so that the surfaces of the mercury halide crystals achieve the dimensions of the acousto-optic device described above.

The step of polishing each surface of the acousto-optic element is to place a mercury halide crystal on a surface located on the Miller index [001] plane, as shown in FIG. 5, with a first side length of 35 mm and located on the Miller index [110] plane. This may be performed after first processing the surface into a virtual rectangular parallelepiped shape where the second side adjacent to the first side has a length of 21 mm.

To form the first side 510, one surface of the rectangular parallelepiped located on the Miller index [001] plane is ground at an angle of approximately 17 degrees at a position corresponding to approximately 11 mm from the lower left corner of the rectangle shown in FIG. 5. You can.

To form the second side 520, the surface located on one side of the first side 510 and located on the Miller index [110] plane may be polished.

To form the third side 530, the surface between the surface located on the Miller index [001] plane and the surface located on the Miller index [110] plane of the virtual cuboid may be polished.

To form the fourth side 540, the surface between the other side of the first side 510 and the surface located on the Miller index [110] plane may be polished.

To form the fifth side 550, the surface located on one side of the third side 530 and located on the Miller index plane may be polished.

To form the sixth side 560, the surface between one side of the fifth side 530 and the other side of the fourth side 540 may be polished.

If necessary, the top and bottom surfaces of the acousto-optic element can also be polished flat.

In the above polishing step, the first side 510 forms approximately 24 mm, the second side 520 forms approximately 4 mm, the third side 530 forms approximately 20 mm, and the fourth side 540 forms approximately 20 mm. It may progress until it forms 16 mm, the fifth side 550 forms approximately 8 mm, and the sixth side 560 forms approximately 13 mm.

The step of combining the transducer 10 can be performed by combining the transducer 10, which has a length of approximately 8 mm or less and is configured to emit a specific sound wave with a center frequency of less than 30 MHz, to one side of the first side 510. . If necessary, a sound absorbing body 50 can be further coupled to the acousto-optical element of the acousto-optical filter 500 according to the fifth embodiment of the present invention.

Above, the specific dimensions of the acousto-optic filter 500 according to the fifth embodiment of the present invention are expressed in millimeters, which corresponds to expressing each dimension as a ratio to the unit length n of 1 mm. However, in the case where the acousto-optic filter 500 is manufactured with dimensions proportional to the above dimensions, that is, the unit length n is set to an arbitrary length greater than 0 and each dimension is set at the same ratio to n, this is also the case. It may be said to fall within the scope of the invention.

Since the acousto-optic filter 500 according to the fifth embodiment of the present invention is formed with a relatively small length/length ratio of the inscribed rectangle, the portion removed from the mercury halide crystal obtained by growth is reduced. This can provide the effect of alleviating the size requirements at which mercury halide crystals must be grown and increasing the efficiency of manufacturing acousto-optic devices.

In addition, the acousto-optic filter 500 according to the fifth embodiment of the present invention not only enables detection of optical components in the long-wavelength infrared band, but also provides very high performance by providing a very wide field of view. can do. That is, the acousto-optic filter 500 according to the fifth embodiment of the present invention can detect light components in the long-wavelength infrared band from a very wide range of angles, providing very high practicality in various fields.

Figure 6 is a plan view illustrating an acousto-optic variable filter 600 according to a sixth embodiment of the present invention. The variable acousto-optic filter 600 according to the sixth embodiment of the present invention has something in common with the variable acousto-optic filter 500 according to the fifth embodiment, and the sixth embodiment will be described below focusing on the differences from the fifth embodiment. Let me explain an example.

The variable acousto-optic filter 600 according to the sixth embodiment of the present invention is formed of a mercury halide material and may include an acousto-optic element having a polyhedral shape and a transducer 10 coupled to one side of the acousto-optic element. . More specifically, the acousto-optical device may be formed by processing mercury bromide (Hg2Br2) crystals.

Figure 6 is a plan view of the variable acousto-optic filter 600, and in Figure 6, the top surface of the polyhedral-shaped acousto-optic element is mainly expressed. In FIG. 6, the lower surface of the acousto-optical element is hidden behind the expressed upper surface, and the plurality of sides (610 to 660) of the polyhedral shape of the acousto-optical element are connected from each side of the upper surface shown in FIG. 6 to the corresponding side of the lower surface. You can.

In the acousto-optic element of the variable acousto-optic filter 600 according to the sixth embodiment of the present invention, the upper surface, lower surface, and plural side surfaces all have a first side length of 35 mm on the surface located on the Miller index plane and Miller index On the surface located on the [110] plane, the second side adjacent to the first side may be formed to be inscribed in a virtual rectangular parallelepiped whose length is 21 mm.

In FIG. 6, the acousto-optic variable filter 600 is depicted with this virtual rectangular parallelepiped, and only one rectangle corresponding to the top surface of the rectangular parallelepiped is shown in the plan view of FIG. 6. As described above, in FIG. 6, the surface corresponding to the upper side of the rectangle is located on the Miller index [001] plane, and the surface corresponding to the side side of the rectangle is located on the Miller index [110] plane. In such a virtual rectangular parallelepiped, the distance between the upper and lower surfaces, that is, the height of each side (610 to 660) of the acousto-optic element of the variable acousto-optic filter 600, is not limited to a specific value.

In the sixth embodiment of the present invention, the plurality of sides of the acousto-optic device may include first to sixth sides 610 to 660. The first side 610 forms an angle between approximately 16.5 and 17.5 degrees with respect to the Miller index [001] plane and may have a length of approximately 24 mm. The second side 620 is bent and connected to one side of the first side 610, is located on the Miller index plane of the above virtual rectangular parallelepiped, and may have a length of approximately 4 mm. The third side 630 is bent and connected to one side of the second side 620, and extends between the surface located on the Miller index [001] plane and the surface located on the Miller index [110] plane of the above virtual rectangular parallelepiped. , may have a length of approximately 20 mm. The fourth side 640 is bent and connected to the other side of the first side 610, and may have a length of approximately 16 mm. The fifth side 650 is bent and connected to one side of the third side 530, is located on the Miller index [001] plane, and may have a length of approximately 17.5 mm. The sixth side 660 extends between one side of the fifth side 630 and the other side of the fourth side 540, is located on the Miller index [110] plane, and may have a length of approximately 8.5 mm.

The transducer 10 may be configured to radiate sound waves by being coupled to the first side 610 of the acousto-optic element. The transducer 10 may have a length of approximately 8 mm or less and the first side 610 It can be combined on one side of . That is, the transducer 10 may have a length of 8 mm or less along the longitudinal direction of the first side 610.

As in the fifth embodiment, when the first side 610 forms a specific angle between 16.5 and 17.5 degrees with respect to the Miller index [001] plane, the angle becomes the acoustic angle. In the graph of Figure 9, looking at the curve with an acoustic angle (α) of 16 degrees and the curve with 18 degrees (the 9th and 10th curves from the left), it can be seen that the curve extends almost vertically in the corresponding part. there is. In other words, in this part, when sound waves are radiated at a specific frequency of less than 30 MHz, light with a wavelength of 10 μm can be diffracted in a very wide range of incident angles (more than 30 degrees).

In the acousto-optic filter 600 according to the sixth embodiment of the present invention, the sound wave enters the first side 610 and propagates along the sound wave area 20 to reach the sixth side 660, and the light beam is transmitted through the third side 660. It enters the side 630, propagates along the light beam area 30, is diffracted by sound waves, and then radiates to the fourth side 640. In the embodiment shown in FIG. 6, when the light beam is incident on the third side 630, which is the incident surface, in a section of about 6 mm corresponding to the light beam area 30, the transducer 10 is activated to transmit a specific signal below about 30 MHz. When a sound wave is generated at a frequency, the light component with a wavelength of 10 μm included in the light beam may be emitted in a section of about 5 mm corresponding to the light beam area 30 of the fourth side 640, which is the emission surface.

The method of manufacturing the acousto-optic filter 600 according to the sixth embodiment of the present invention includes preparing a mercury halide crystal, processing the mercury halide crystal into the acousto-optic element, and combining the transducer 10. It may include steps.

The step of preparing a mercury halide crystal is a process in which the length of the first side on the surface located on the Miller index [001] plane is 35 mm and the length of the second side adjacent to the first side on the surface located on the Miller index [110] plane is 21 mm. A step of preparing mercury halide crystals with a volume larger than a virtual rectangular parallelepiped may be included. For example, this involves growing a mercury bromide (Hg2Br2) crystal to a size large enough to contain the cuboid inside, with the side surfaces of the above cuboid aligned on the Miller index [001] plane and the Miller index [110] plane. It can also be accomplished through a process.

Processing the mercury halide crystals into an acousto-optic device may include polishing the mercury halide crystals so that the surfaces of the mercury halide crystals achieve the dimensions of the acousto-optic device described above.

The step of polishing each surface of the acousto-optic element is to place a mercury halide crystal on a surface located on the Miller index [001] plane, as shown in FIG. 6, with a first side length of 35 mm and located on the Miller index [110] plane. It may include first processing the surface into a virtual rectangular parallelepiped shape where the second side adjacent to the first side has a length of 21 mm.

Then, to form the first side 610, one surface of the cuboid located on the Miller index [001] plane is cut at an angle of approximately 17 degrees at a position corresponding to approximately 11 mm from the lower left corner of the rectangle shown in FIG. It can be polished.

To form the third side 630, the surface between the surface located on the Miller index [001] plane and the surface located on the Miller index [110] plane of the virtual cuboid may be polished.

To form the fourth side 640, the surface between the other side of the first side 610 and the surface located on the Miller index [110] plane may be polished.

The second side 620, the fifth side 650, and the sixth side 660 are part of the previously processed rectangular parallelepiped and do not require separate processing.

In the above polishing step, the first side 610 forms approximately 24 mm, the second side 620 forms approximately 4 mm, the third side 630 forms approximately 20 mm, and the fourth side 640 forms approximately 20 mm. It may progress until it forms 16 mm, the fifth side 650 forms approximately 17.5 mm, and the sixth side 660 forms approximately 8.5 mm.

The step of combining the transducer 10 can be performed by combining the transducer 10, which has a length of approximately 8 mm or less and is configured to emit a specific sound wave with a center frequency of less than 30 MHz, to one side of the first side 610. . If necessary, a sound absorbing body 50 can be further combined with the acousto-optical element of the acousto-optic filter 600 according to the sixth embodiment of the present invention.

Above, the specific dimensions of the acousto-optic filter 600 according to the sixth embodiment of the present invention are expressed in millimeters, which corresponds to expressing each dimension as a ratio to the unit length n of 1 mm. However, in the case where the acousto-optic filter 600 is manufactured with dimensions proportional to the above dimensions, that is, the unit length n is set to an arbitrary length greater than 0 and each dimension is set at the same ratio to n, this is also the case. It may be said to fall within the scope of the invention.

Since the acousto-optic filter 600 according to the sixth embodiment of the present invention is formed with a relatively small length/length ratio of the inscribed rectangle, the portion removed from the mercury halide crystal obtained by growth is reduced. This can provide the effect of alleviating the size requirements at which mercury halide crystals must be grown and increasing the efficiency of manufacturing acousto-optic devices. In the acousto-optic filter 600 according to the sixth embodiment of the present invention, the amount of polishing of the acousto-optic element is lower than that of the acousto-optic filter 500 according to the fifth embodiment, making it easier to manufacture and less likely to cause splitting. low.

In addition, the acousto-optic filter 600 according to the sixth embodiment of the present invention not only enables detection of optical components in the long-wavelength infrared band, but also provides very high performance by providing a very wide field of view. can do. That is, the acousto-optic filter 500 according to the sixth embodiment of the present invention can detect optical components in the long-wavelength infrared band from a very wide range of angles, providing very high practicality in various fields.

Figure 7 is a plan view illustrating an acousto-optic variable filter 700 according to a seventh embodiment of the present invention.

The variable acousto-optic filter 700 according to the seventh embodiment of the present invention is formed of a mercury halide material and may include an acousto-optic element having a polyhedral shape and a transducer 10 coupled to one side of the acousto-optic element. . More specifically, the acousto-optical device may be formed by processing mercury bromide (Hg2Br2) crystals.

FIG. 7 is a plan view of the variable acousto-optic filter 700, and in FIG. 7, the top surface of the polyhedral-shaped acousto-optic element is mainly expressed. In FIG. 7, the lower surface of the acousto-optic element is hidden behind the expressed upper surface, and the plurality of sides (710 to 740) of the polyhedral shape of the acousto-optical element are connected from each side of the upper surface shown in FIG. 7 to the corresponding side of the lower surface. You can.

In the acousto-optic element of the variable acousto-optic filter 700 according to the seventh embodiment of the present invention, the upper surface, lower surface, and plural side surfaces all have a first side length of 50 mm on the surface located on the Miller index plane and Miller index On the surface located on the [110] plane, the second side adjacent to the first side may be formed to be inscribed in a virtual rectangular parallelepiped whose length is 29 mm.

In FIG. 7, the variable acousto-optic filter 700 is depicted along with this virtual rectangular parallelepiped, and only one rectangle corresponding to the upper surface of the rectangular parallelepiped is shown in the plan view of FIG. 7. As described above, in FIG. 7, the surface corresponding to the upper side of the rectangle is located on the Miller index [001] plane, and the surface corresponding to the side side of the rectangle is located on the Miller index [110] plane. In such a virtual rectangular parallelepiped, the distance between the upper and lower surfaces, that is, the height of each side (710 to 740) of the acousto-optic element of the variable acousto-optic filter 700, is not limited to a specific value.

In the seventh embodiment of the present invention, the plurality of sides of the acousto-optic device may include first to fourth sides 710 to 740. The first side 710 forms an angle between about 16.5 and 17.5 degrees with respect to the Miller index [001] plane and may have a length of approximately 40 mm. The second side 720 is bent and connected to one side of the first side 710, and extends between the surface located on the Miller index [001] plane and the surface located on the Miller index [110] plane of the above virtual rectangular parallelepiped. , may have a length of approximately 37 mm. The third side 730 is bent and connected to the other side of the first side 710, and may have a length of approximately 16 mm. The fourth side 750 extends between one side of the second side 720 and the other side of the third side 730, and may have a length of approximately 25 mm.

The transducer 10 may be configured to radiate sound waves by being coupled to the first side 710 of the acousto-optic element. The transducer 10 may have a length of approximately 14 mm or less and the first side 710 It can be combined on one side of . That is, the transducer 10 may have a length of 14 mm or less along the longitudinal direction of the first side 710.

The design dimensions of the variable acousto-optic filter 700 according to the seventh embodiment of the present invention shown in FIG. 7 are as shown in [Table 4] below.

Design dimensions of variable acousto-optic filter X size [001] [mm] 50 Y size [110] [mm] 29 transducer length [mm] 14 acoustic angle [Angle] 16.5~17.5 entrance surface [mm] 37 exit surface [mm] 16 Transducer side [mm] 40 center frequency [MHz] less than 30

Referring to FIG. 7, the first side 710 becomes the transducer surface, the second side 720 becomes the incident surface of the light beam, and the third side 730 becomes the exit surface of the diffracted light. When the transducer 10 coupled to the first side 710 radiates a sound wave with a center frequency of less than 30 MHz, the sound wave is inclined by the walk-off angle (ω) with respect to the normal direction of the first side 710, which is the transducer surface. The light beam that travels within the sound wave area 20 and flows into the second side 720, which is the incident surface, is diffracted by modulation of the sound wave and radiates along the light beam area 30 to the third side 730, which is the exit surface. Can be detected by a separate device.

When the first side 710 forms a specific angle between 16.5 and 17.5 degrees with respect to the Miller index [001] plane, the angle becomes the acoustic angle. In the graph of Figure 9, looking at the curve with an acoustic angle (α) of 16 degrees and the curve with 18 degrees (the 9th and 10th curves from the left), it can be seen that the curve extends almost vertically in the corresponding part. there is. In other words, in this part, when sound waves are radiated at a specific frequency of less than 30 MHz, light with a wavelength of 10 μm can be diffracted in a very wide range of incident angles (more than 30 degrees).

In the acousto-optic filter 700 according to the seventh embodiment of the present invention, the sound wave enters the first side 710 and propagates along the sound wave area 20 to reach the fourth side 740, and the light beam is transmitted through the second side 740. It enters the side 720, propagates along the light beam area 30, is diffracted by sound waves, and then radiates to the third side 730. In the embodiment shown in FIG. 7, when the light beam is incident on the second side 720, which is the incident surface, in a section of about 12 mm corresponding to the light beam area 30, the transducer 10 is activated to transmit a specific signal below about 30 MHz. When a sound wave is generated at a frequency, the light component with a wavelength of 10 μm included in the light beam may be emitted in a section of about 11 mm corresponding to the light beam area 30 of the third side 730, which is the emission surface.

The method of manufacturing the acousto-optic filter 700 according to the seventh embodiment of the present invention includes preparing a mercury halide crystal, processing the mercury halide crystal into the acousto-optic element, and combining the transducer 10. It may include steps.

The step of preparing a mercury halide crystal is a process in which the length of the first side on the surface located on the Miller index [001] plane is 50 mm, and the length of the second side adjacent to the first side on the surface located on the Miller index [110] plane is 29 mm. A step of preparing mercury halide crystals with a volume larger than a virtual rectangular parallelepiped may be included. For example, this involves growing a mercury bromide (Hg2Br2) crystal to a size large enough to contain the cuboid inside, with the side surfaces of the above cuboid aligned on the Miller index [001] plane and the Miller index [110] plane. It can also be accomplished through a process.

Processing the mercury halide crystals into an acousto-optic device may include polishing the mercury halide crystals so that the surfaces of the mercury halide crystals achieve the dimensions of the acousto-optic device described above.

The step of polishing each surface of the acousto-optic element is to place a mercury halide crystal on a surface located on the Miller index [001] plane, as shown in FIG. 7, with a first side length of 50 mm and located on the Miller index [110] plane. This may be performed after first processing the surface into a virtual rectangular parallelepiped shape where the second side adjacent to the first side has a length of 29 mm.

To form the first side 710, one surface of the cuboid located on the Miller index [001] plane can be ground at an angle of approximately 17 degrees at a specific location from the lower left corner of the rectangle shown in FIG. 7.

To form the second side 720, the surface between the surface located on the Miller index [001] plane and the surface located on the Miller index [110] plane of the virtual cuboid may be polished.

To form the third side 730, the surface between the other side of the first side 710 and the surface located on the Miller index [110] plane may be polished.

To form the fourth side 740, the surface between one side of the second side 720 and the other side of the third side 730 may be polished.

If necessary, the top and bottom surfaces of the acousto-optic element can also be polished flat.

In the above polishing step, the first side 710 forms approximately 40 mm, the second side 720 forms approximately 37 mm, the third side 730 forms approximately 16 mm, and the fourth side 740 forms approximately 16 mm. It can progress until 25mm is achieved.

The step of combining the transducer 10 can be performed by combining the transducer 10, which has a length of approximately 14 mm or less and is configured to emit a specific sound wave with a center frequency of less than 30 MHz, to one side of the first side 710. . If necessary, a sound absorbing body 50 may be further coupled to the acousto-optical element of the acousto-optical filter 700 according to the seventh embodiment of the present invention.

Above, the specific dimensions of the acousto-optic filter 700 according to the seventh embodiment of the present invention are expressed in millimeters, which corresponds to expressing each dimension as a ratio to the unit length n of 1 mm. However, in the case where the acousto-optic filter 700 is manufactured with dimensions proportional to the above dimensions, that is, the unit length n is set to an arbitrary length greater than 0 and each dimension is set at the same ratio to n, this is also the case. It may be said to fall within the scope of the invention.

The acousto-optic filter 700 according to the seventh embodiment of the present invention is more sensitive to the light component in the long-wavelength infrared band because the light beam area 30 through which the light beam passes is formed over a relatively wide section at the entrance and exit surfaces. It is possible to detect it accurately. In particular, the acousto-optic filter 700 according to the seventh embodiment of the present invention, like the acousto-optic filters 500 and 600 according to the fifth and sixth embodiments, can provide a very wide viewing angle and provide very high performance. there is.

Figure 8 is a plan view illustrating an acousto-optic variable filter 800 according to an eighth embodiment of the present invention. The tunable acousto-optic filter 800 according to the eighth embodiment of the present invention has something in common with the tunable acousto-optic filter 700 according to the 7th embodiment. Below, the 8th embodiment focuses on the differences from the 7th embodiment. Let me explain an example.

The variable acousto-optic filter 800 according to the eighth embodiment of the present invention is formed of a mercury halide material and includes an acousto-optic element having a polyhedral shape and a transducer 10 coupled to one side of the acousto-optic element. . More specifically, the acousto-optical device may be formed by processing mercury bromide (Hg2Br2) crystals.

FIG. 8 is a plan view of the variable acousto-optic filter 800, and in FIG. 8, the top surface of the polyhedral-shaped acousto-optic element is mainly expressed. In FIG. 8, the lower surface of the acousto-optical element is hidden behind the expressed upper surface, and the plurality of sides (810 to 850) of the polyhedral shape of the acousto-optical element are connected from each side of the upper surface shown in FIG. 8 to the corresponding side of the lower surface. You can.

In the acousto-optic element of the variable acousto-optic filter 800 according to the eighth embodiment of the present invention, the upper surface, lower surface, and plural side surfaces all have a first side length of 50 mm on the surface located on the Miller index plane and Miller index On the surface located on the [110] plane, the second side adjacent to the first side may be formed to be inscribed in a virtual rectangular parallelepiped whose length is 29 mm.

In FIG. 8, the acousto-optic variable filter 800 is depicted along with this virtual rectangular parallelepiped, and only one rectangle corresponding to the upper surface of the rectangular parallelepiped is shown in the plan view of FIG. 8. As described above, in FIG. 8, the surface corresponding to the upper side of the rectangle is located on the Miller index [001] plane, and the surface corresponding to the side side of the rectangle is located on the Miller index [110] plane. In such a virtual rectangular parallelepiped, the distance between the upper and lower surfaces, that is, the height of each side (810 to 850) of the acousto-optic element of the variable acousto-optic filter 800, is not limited to a specific value.

In the eighth embodiment of the present invention, the plurality of sides of the acousto-optic device may include first to fifth sides 810 to 850. The first side 810 forms an angle between approximately 16.5 and 17.5 degrees with respect to the Miller index [001] plane and may have a length of approximately 40 mm. The second side 820 is bent and connected to one side of the first side 810, and extends between the surface located on the Miller index [001] plane and the surface located on the Miller index [110] plane of the above virtual rectangular parallelepiped. , may have a length of approximately 37 mm. The third side 830 is bent and connected to the other side of the first side 810, and may have a length of approximately 16 mm. The fourth side 840 is bent and connected to one side of the second side 720, is located on the Miller index [001] plane, and may have a length of approximately 17.5 mm. The fifth side 850 is bent and connected to the other side of the third side 830, is located on the Miller index [110] plane, and may have a length of approximately 8 mm.

The transducer 10 may be configured to radiate sound waves by being coupled to the first side 810 of the acousto-optic element. The transducer 10 may have a length of approximately 14 mm or less and the first side 810 It can be combined on one side of . That is, the transducer 10 may have a length of 14 mm or less along the longitudinal direction of the first side 810.

As in the seventh embodiment, when the first side 810 forms a specific angle between 16.5 and 17.5 degrees with respect to the Miller index [001] plane, the angle becomes the acoustic angle. In the graph of Figure 9, looking at the curve with an acoustic angle (α) of 16 degrees and the curve with 18 degrees (the 9th and 10th curves from the left), it can be seen that the curve extends almost vertically in the corresponding part. there is. In other words, in this part, when sound waves are radiated at a specific frequency of less than 30 MHz, light with a wavelength of 10 μm can be diffracted in a very wide range of incident angles (more than 30 degrees).

In the acousto-optic filter 800 according to the eighth embodiment of the present invention, the sound wave enters the first side 810 and propagates along the sound wave area 20 to reach the fifth side 850, and the light beam is transmitted through the second side 850. It enters the side 820, propagates along the light beam area 30, is diffracted by sound waves, and then radiates to the third side 830. In the embodiment shown in FIG. 8, when the light beam is incident on the second side 820, which is the incident surface, in a section of about 12 mm corresponding to the light beam area 30, the transducer 10 is activated to transmit a specific signal below about 30 MHz. When a sound wave is generated at a frequency, the light component with a wavelength of 10 μm included in the light beam may be emitted in a section of about 11 mm corresponding to the light beam area 30 of the third side 830, which is the emission surface.

The method of manufacturing the acousto-optic filter 800 according to the eighth embodiment of the present invention includes preparing a mercury halide crystal, processing the mercury halide crystal into the acousto-optic element, and combining the transducer 10. It may include steps.

The step of preparing a mercury halide crystal is a process in which the length of the first side on the surface located on the Miller index [001] plane is 50 mm, and the length of the second side adjacent to the first side on the surface located on the Miller index [110] plane is 29 mm. A step of preparing mercury halide crystals with a volume larger than a virtual rectangular parallelepiped may be included. For example, this involves growing a mercury bromide (Hg2Br2) crystal to a size large enough to contain the cuboid inside, with the side surfaces of the above cuboid aligned on the Miller index [001] plane and the Miller index [110] plane. It can also be accomplished through a process.

Processing the mercury halide crystals into an acousto-optic device may include polishing the mercury halide crystals so that the surfaces of the mercury halide crystals achieve the dimensions of the acousto-optic device described above.

The step of polishing each surface of the acousto-optic element is to place a mercury halide crystal on a surface located on the Miller index [001] plane, as shown in FIG. 8, with a first side length of 50 mm and located on the Miller index [110] plane. It may include first processing the surface into a virtual rectangular parallelepiped shape, where the second side adjacent to the first side has a length of 29 mm.

Then, to form the first side 810, one surface of the cuboid located on the Miller index [001] plane can be ground at an angle of approximately 17 degrees at a specific location from the lower left corner of the rectangle shown in Figure 8. there is.

To form the second side 820, the surface between the surface located on the Miller index [001] plane and the surface located on the Miller index [110] plane of the virtual cuboid may be polished.

To form the third side 830, the surface between the other side of the first side 810 and the surface located on the Miller index [110] plane may be polished.

The fourth side 840 and the fifth side 850 are part of the previously processed rectangular parallelepiped and do not require separate processing.

In the above polishing step, the first side 810 forms approximately 40 mm, the second side 820 forms approximately 37 mm, the third side 830 forms approximately 16 mm, and the fourth side 840 forms approximately 16 mm. It can progress until it forms 17.5 mm, and the fifth side 830 forms approximately 8 mm.

The step of combining the transducer 10 can be performed by combining the transducer 10, which has a length of approximately 14 mm or less and is configured to emit a specific sound wave with a center frequency of less than 30 MHz, to one side of the first side 810. . If necessary, a sound absorbing body 50 can be further combined with the acousto-optical element of the acousto-optical filter 800 according to the eighth embodiment of the present invention.

Above, the specific dimensions of the acousto-optic filter 800 according to the eighth embodiment of the present invention are expressed in millimeters, which corresponds to expressing each dimension as a ratio to the unit length n of 1 mm. However, in the case where the acousto-optic filter 800 is manufactured with dimensions proportional to the above dimensions, that is, the unit length n is set to an arbitrary length greater than 0 and each dimension is set at the same ratio to n, this is also the case. It may be said to fall within the scope of the invention.

The acousto-optic filter 800 according to the eighth embodiment of the present invention is more sensitive to the light component in the long-wavelength infrared band because the light beam area 30 through which the light beam passes is formed over a relatively wide section at the entrance and exit surfaces. It is possible to detect it clearly. In particular, the acousto-optic filter 800 according to the eighth embodiment of the present invention, like the acousto-optic filters 500, 600, and 700 according to the fifth to seventh embodiments, provides a very wide viewing angle and provides very high performance. can do. Meanwhile, in the acousto-optic filter 800 according to the eighth embodiment of the present invention, the amount of polishing of the acousto-optic element is lower than that of the acousto-optic filter 700 according to the seventh embodiment of the present invention, making it easier to manufacture and less likely to cause splitting. is lower.

Although the present invention has been described above with reference to an embodiment of the present invention, those skilled in the art will understand the present invention in various ways without departing from the spirit and scope of the present invention as set forth in the claims below. You will understand that it can be modified and changed.

Claims (6)

It is made of a mercury halide material and has a polyhedral shape with an upper surface, a lower surface, and a plurality of side surfaces. For unit length n, the upper surface, the lower surface, and the plurality of side surfaces are all located on the Miller index plane [001]. An acousto-optic element formed to be inscribed in a virtual rectangular parallelepiped, where one side has a length of 35n and a second side adjacent to the first side has a length of 21n on a surface located on the Miller index [110] plane; and
A transducer coupled to one of the plurality of sides and configured to emit sound waves,
The plurality of aspects is,
a first side having a length of 24n and making an angle between 16.5 and 17.5 degrees with respect to the Miller index [001] plane;
a second side that is bent and connected to one side of the first side, is located on the Miller index [110] plane, and has a length of 4n;
A third side is bent at one side of the second side, extends between a surface located on the Miller index [110] plane of the virtual rectangular parallelepiped, and a surface located on the Miller index [001] plane, and has a length of 20n. ; and
A fourth side is bent and connected to the other side of the first side and has a length of 16n,
The transducer is coupled to one side of the first side, and has a length of 8n or less along the longitudinal direction of the first side.
According to claim 7,
The plurality of aspects is,
A variable acousto-optic filter further comprising a fifth side that is bent and connected to one side of the third side and located on the Miller index [001] plane.
According to claim 2,
The fifth side has a length of 8n,
The plurality of side surfaces further include a sixth side extending between one side of the fifth side and the other side of the fourth side.
It is made of a mercury halide material and has a polyhedral shape with an upper surface, a lower surface, and a plurality of side surfaces. For unit length n, the upper surface, the lower surface, and the plurality of side surfaces are all located on the Miller index plane [001]. An acousto-optic element formed to be inscribed in a virtual rectangular parallelepiped, where one side has a length of 50n and a second side adjacent to the first side has a length of 29n on a surface located on the Miller index [110] plane; and
A transducer coupled to one of the plurality of sides and configured to emit sound waves,
The plurality of aspects is,
a first side having a length of 40n and making an angle between 16.5 and 17.5 degrees with respect to the Miller index [001] plane;
A second side is bent at one side of the first side, extends between a surface located on the Miller index [001] plane of the virtual cuboid, and a surface located on the Miller index [110] plane, and has a length of 37n. ; and
A third side is bent and connected to the other side of the first side and has a length of 16n,
The transducer is coupled to one side of the first side, and has a length of 14n or less along the longitudinal direction of the first side.

According to claim 4,
The plurality of side surfaces further include a fourth side extending between one side of the second side and the other side of the third side.
According to claim 4,
The plurality of aspects is,
a fourth side that is bent and connected to one side of the second side and is located on the Miller index [001] plane; and
The acousto-optic variable filter further includes a fifth side that is bent and connected to the other side of the third side and is located on the Miller index [110] plane.