WO2024071668A1 - Polarization-splitting double-scanning holography system for transmission body - Google Patents

Abstract

The present invention relates to a polarization-splitting double-scanning holography system for a transmission body. The polarization-splitting double-scanning holography system according to the present invention comprises: a scan beam generation unit which modulates the phase of a first beam split from a light source to transform the first beam into a first curvature beam and transform a second beam into a second curvature beam, and then makes the first and second curvature beams interfere with each other to form a scan beam; a scan beam splitting unit which splits the scan beam into an s-polarized beam and a p-polarized beam and projects the beams side by side; a scanning unit which receives a scan beam comprising two polarized beams emitted side by side, projects the scan beam onto a transmission body, and controls the scanning position of the scan beam with respect to the object in the horizontal and vertical directions to transmit the scan beam to the transmission body; a photodetection unit which separates and detects the s-polarized beam and the p-polarized beam from the beam that has passed through the transmission body; and a signal processing unit which processes signals of the detected s-polarized and p-polarized beams to generate a hologram of the transmission body. According to the present invention, the hologram of the transmission body can be acquired at ultra-high speed, faster than the scanning speed of a scanning mirror.

Description

Polarization splitting double scanning holography system for transmitting materials

The present invention relates to a polarization-splitting double scanning holography system for a transmissive object, and more specifically, to a polarization-splitting double scanning holography system for a transmissive object that can implement a scanning hologram for a transmissive object, which is a transmissive object, at ultra-high speed.

A conventional optical scanning hologram system uses an interferometer to form a beam pattern with a spatial distribution of a Fresnel zone plate, projects the formed beam pattern onto an object, and condenses the light reflected or transmitted from the object. A hologram of an object is obtained through detection.

However, in this conventional method, there is a problem that the speed of acquiring a hologram is dependent on the scanning speed of the scanning mirror.

Therefore, a new technique that can acquire a hologram of an object faster than the scanning speed of a scanning mirror is required.

The technology behind the present invention is disclosed in Korean Patent No. 1304695 (announced on September 6, 2013).

The purpose of the present invention is to provide a polarization splitting double scanning holography system for a transmissive object that can implement a scanning hologram for a transmissive object at ultra-high speed.

The present invention modulates the phase of the first beam split from the light source, converts it into a first curvature beam through the first beam curvature generator, and converts the second beam into a second curvature beam through the second beam curvature generator, A scan beam generator that forms a scan beam by interfering with the first and second curvature beams, and splits the scan beam into an s-polarized beam and a p-polarized beam to emit the two divided polarized beams side by side. A scan beam consisting of a beam splitter and two polarized beams emitted side by side is received from the scan beam splitter and projected onto a transmitting body, and the scanning position of the scan beam with respect to the transmitting body is controlled in the horizontal and vertical directions. A scanning unit that transmits the signal to a transmitting body, a light detecting unit that separates and detects the s-polarized beam and the p-polarized beam from the beam that has transmitted through the transmitting body, and a signal of the separately detected s-polarized beam and the p-polarized beam. It provides a polarization splitting double scanning holography system for a transmitting object, including a signal processing unit that processes the transmitting object to generate a hologram for the transmitting object.

In addition, the light detection unit is disposed in a direction biased to the optical axis of the beam projected to the transmitting body, and includes a first concentrator that condenses the beam that has transmitted through the transmitting body, and a beam spatially integrated through the first concentrator. a first polarizer that passes only the s-polarized beam component, a first photodetector that detects the s-polarized beam that has passed through the first polarizer, and a first polarizer disposed in a direction biased to the optical axis of the beam projected to the transmitting body; 1 a second concentrator disposed in a position different from the concentrator and concentrating the beam that has passed through the transmitting body, a second polarizer that passes only the p-polarized beam component in the spatially integrated beam through the second concentrator, and It may include a second photodetector that detects the p-polarized beam that has passed through the second polarizer.

In addition, the light detection unit includes a first light splitter disposed on the optical axis of the light projected to the transmitting body and receiving the beam passing through the transmitting body and reflecting it to the outside, and receiving the light reflected from the first light splitter and receiving the light reflected from the first light splitter. a second light splitter that transmits the p-polarized beam component of the incident beam and reflects the s-polarized beam component, a first concentrator that condenses the s-polarized beam component reflected by the second light splitter, and the second light splitter A second concentrator for concentrating the p-polarized beam component transmitted from the light splitter, a first photodetector for detecting the spatially integrated beam through the first concentrator, and a spatially integrated beam through the second concentrator. It may include a second photodetector that detects.

In addition, the light detection unit includes a first light splitter disposed on the optical axis of the light projected to the transmitting body and receiving the beam passing through the transmitting body and reflecting it to the outside, and receiving the light reflected from the first light splitter and receiving the light reflected from the first light splitter. A second light splitter that transmits part of the incident beam and reflects part of it, a first polarizer that receives the beam reflected from the second light splitter and allows only the s-polarized beam component to pass through, and is transmitted by the second light splitter. a second polarizer that receives the incident beam and allows only the p-polarized beam component to pass through, a first concentrator that condenses the s-polarized beam component that has passed through the first polarizer, and a p-polarized beam that has passed through the second polarizer. It may include a second concentrator for concentrating a component, a first photodetector for detecting a spatially integrated beam through the first concentrator, and a second photodetector for detecting a spatially integrated beam through the second concentrator. You can.

In addition, the signal processor includes a first signal processor that processes the signal of the s-polarized beam detected by the first photodetector, and a second signal processor that processes the signal of the p-polarized beam detected by the second photodetector. It may include a processing unit, and a cross-array signal processing unit that generates a hologram for the transmitting body by synthesizing the hologram signal processed in the first signal processing unit and the hologram signal processed in the second signal processing unit in a manner that cross-arranges them line by line. You can.

In addition, the scan beam splitter is made of an anisotropic optical material, and separates the scan beam incident through the first side into an s-polarized beam and a p-polarized beam with polarizations orthogonal to each other and emits them in parallel through the second side. It may include a beam displacer.

In addition, the scan beam splitter is installed on the path of the shorter p-polarized beam among the paths of the s-polarized beam and the p-polarized beam emitted through the second surface, and is made of the same material as the beam displacer. It may further include an optical path difference correction unit that compensates for the difference in optical path length between the emitted s-polarized beam and the p-polarized beam.

In addition, the scan beam splitter is composed of a combination of two triangular prisms whose crystal axes are perpendicular to each other and made of different materials, and the scan beam incident through the first surface is transmitted parallel to the scan beam at the boundary surface of the two triangular prisms. It includes a polarizing prism that separates a first polarized beam and a second polarized beam that travels at a set angle from the scan beam and emits them through a second surface, and if the first polarized beam is an s-polarized beam, the second polarized beam The polarized beam may be a p-polarized beam, and if the first polarized beam is a p-polarized beam, the second polarized beam may be an s-polarized beam.

In addition, the scan beam splitter is sequentially installed on the path of the second polarized beam emitted through the second surface to change the beam path to determine the direction of travel of the second polarized beam. a displacement control unit that adjusts the scan beam in parallel, and a first polarized beam that is installed on the path of the shorter s-polarized beam among the paths of the first and second polarized beams that are emitted through the second surface, and is emitted; It may further include an optical path difference correction unit that compensates for a difference in optical path length between the second polarized beams.

In addition, the optical path difference correction unit includes third to sixth mirrors that are sequentially installed on the path of the first polarized beam emitted through the second surface to change the beam path, and the third and sixth mirrors It may include a mirror moving unit that compensates for the difference in optical path length while moving the fourth and fifth mirrors arranged in parallel and spaced apart from the mirror as a group.

Additionally, the polarizing prism may have a Rochon prism or Senarmont prism structure.

In addition, the polarizing prism is installed in a state rotated by a set angle based on the center of the boundary surface, and the set angle is the angle between the travel directions of the first polarization beam and the second polarization beam separately emitted from the center of the boundary surface. It may be θ/2, which is half of the difference (θ).

In addition, the scan beam splitter includes first and second mirrors that are sequentially installed on the path of the second polarized beam emitted through the second surface to change the beam path, and a first and second mirrors that are sequentially installed on the path of the second polarized beam emitted through the second surface. 1. It further includes a displacement control unit including third and fourth mirrors that are sequentially installed on the path of the polarized beam to change the beam path and are installed symmetrically with the first and second mirrors, and wherein the displacement control unit The travel directions of the second polarized beam that has passed through the second mirror and the first polarized beam that has passed through the fourth mirror may be adjusted to be parallel.

In addition, the scan beam splitter is composed of a combination of two triangular prisms whose crystal axes are perpendicular to each other and made of different materials, and the scan beam incident through the first surface is divided into two triangular prisms at the boundary surface of the two triangular prisms in the direction of the scan beam. It may include a polarizing prism of a Wollaston prism structure that separates the s-polarized beam and the p-polarized beam, which proceed symmetrically to each other at a set angle, and emits them through the second surface.

In addition, the scan beam splitter includes first and second mirrors that are sequentially installed on the path of the p-polarized beam emitted through the second surface to change the beam path, and s emitted through the second surface. -It further includes a displacement control unit including third and fourth mirrors that are sequentially installed on the path of the polarizing beam to change the beam path and are installed symmetrically with the first and second mirrors, and are operated by the displacement control unit. The travel directions of the p-polarized beam that passed through the second mirror and the s-polarized beam that passed through the fourth mirror may be adjusted to be parallel.

In addition, the scan beam splitter includes a first polarizing beam splitter that reflects the s-polarized beam component from the incident scan beam and transmits the p-polarized beam component, and a first polarizing beam splitter that reflects the s-polarized beam component from the first polarizing beam splitter. First and second mirrors are sequentially installed on the path to change the beam path by 90 degrees, and are sequentially installed on the path of the p-polarized beam transmitted from the first polarizing beam splitter to change the beam path by 90 degrees. The third to sixth mirrors, and an s-polarized beam that has passed through the second mirror and a p-polarized beam that has passed through the sixth mirror, are incident on each of the first and second surfaces, and after incident on the first face, It may include a second polarizing beam splitter that outputs the reflected s-polarized beam and the p-polarized beam transmitted after incident on the second surface in a parallel direction through the third surface.

In addition, the scan unit includes a horizontal scan mirror and a vertical scan mirror to control the scanning position of the scan beam with respect to the transmitting object, and can control the incident scan beam in horizontal and vertical directions and transmit it to the transmitting object.

In addition, the scan unit includes a scan mirror that controls the scan beam incident from the scan beam splitter in the horizontal direction and transmits it to the transmissive body so as to control the scanning position of the scan beam with respect to the transmissive body in the horizontal and vertical directions; A translation stage may be included at the rear end of the transparent body to move the transparent material in the vertical direction.

In addition, the scan unit controls the scan beam incident from the scan beam splitter in the horizontal direction to control the scanning position of the scan beam with respect to the transmissive body in the horizontal and vertical directions and transmits it to the transmissive body through spatial modulation (spatial modulation). modulation) may include a scanner and a translation stage that moves the transparent material in the vertical direction at the rear end of the transparent material.

In addition, the scan unit includes a vertical scanner and a horizontal scanner for controlling the scanning position of the scan beam with respect to the object in horizontal and vertical directions, and controls the scan beam incident from the scan beam splitter in the horizontal direction. It may include a horizontal spatial modulation scanner that transmits the scan beam to an object, and a vertical spatial modulation scanner that controls the scan beam in the vertical direction and transmits it to the object.

According to the present invention, it is possible to obtain a hologram for a transparent object at ultra-high speed, faster than the scanning speed of a scan mirror.

Figure 1 is a diagram showing the configuration of a polarization-splitting double scanning holography system for a transmissive material according to a first embodiment of the present invention.

Figure 2a is a diagram showing the configuration of a polarization-splitting double scanning holography system for a transmissive material according to a second embodiment of the present invention.

FIG. 2B is a diagram showing a modified example of FIG. 2A.

Figure 3 is a diagram showing the configuration of a polarization-splitting double scanning holography system for a transmissive material according to a third embodiment of the present invention.

Figure 4a is a diagram showing the configuration of a polarization-splitting double scanning holography system for a transmissive material according to a fourth embodiment of the present invention.

FIG. 4B is a diagram showing a modified example of FIG. 4A.

FIGS. 5A to 5H are diagrams illustrating various embodiments of the scan beam splitter shown in FIG. 1.

Figure 6 is a diagram explaining the operation of a signal processing unit according to an embodiment of the present invention.

Figure 7 is a diagram explaining the operating principle of a spatial modulation scanner.

Figure 8 is a diagram explaining the operating principle of the horizontal and vertical spatial modulation scanner.

Then, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts that are not related to the description are omitted, and similar parts are given similar reference numerals throughout the specification.

Throughout the specification, when a part is said to be "connected" to another part, this includes not only the case where it is "directly connected," but also the case where it is "electrically connected" with another element in between. . Additionally, when a part "includes" a certain component, this means that it may further include other components rather than excluding other components, unless specifically stated to the contrary.

The present invention relates to a polarization-splitting double scanning holography system for a transmissive object, and proposes a polarization-splitting double scanning holography system for acquiring a hologram for a transmissive object (hereinafter referred to as a transmissive object) at high speed.

In the present invention, the beam generated by the scan beam generator is divided into an s-polarized beam and a p-polarized beam, and the beam is emitted side by side and projected onto a transmitting object, which is the object to be scanned, and the beam transmitted through the transmitting object is condensed and sent to the light detection unit. We propose an optical system structure that implements a hologram for a transmitting object at high speed by processing the s-polarized beam and p-polarized beam that are separately detected by the light detection unit after transmission.

Hereinafter, the polarization splitting double scanning holography system for a transmissive material according to an embodiment of the present invention will be described in more detail with reference to the drawings.

1 to 4 are diagrams showing the configuration of a polarization-splitting double scanning holography system for a transmissive material according to the first to fourth embodiments of the present invention.

First, as shown in FIG. 1, the polarization splitting double scanning holography system 100 for a transmitting body according to the first embodiment of the present invention largely includes a scan beam generator 110, a scan beam splitter 120, and a scan unit ( 130), a light detection unit 140, and a signal processing unit 150. This basic structure also applies to the remaining second to fourth embodiments.

First, the scan beam generator 110 converts the first beam of the first and second beams split from the light source into a first curvature beam through the first lens 115 by frequency shifting, and converts the second beam into a second beam. After being converted into a second curvature beam through the lens 116, the first and second curvature beams are interfered to form a scan beam.

The scan beam generator 110 uses a mark-gender interferometer structure that splits a light source into first and second beams to generate first and second curved beams, and then combines the two generated beams again.

The scan beam generator 110 includes a first mirror (M1), a light splitter 111, a frequency shift means 112, second and third mirrors (M2, M3), and first and second beam curvature generators ( N1, N2), and an interference means 117, and may further include a light source.

The light source is the part that generates electromagnetic waves. The light source may include various means such as a laser generator capable of generating electromagnetic waves, a light emitting diode (LED), and a beam with low coherence such as helogen light with a short coherence length. Below, the light source implemented as a laser generator is taken as a representative example.

The beam output from the light source is transmitted to the first mirror (M1) and then reflected and input to the light splitter 111.

The light splitter 111 separates the incident beam into a first beam and a second beam, transmits the first beam to the phase modulation means 112 (acoustic-optical modulator), and transfers the second beam to the third mirror M3. Pass it to That is, the beam following the path of the first beam from the optical splitter 111 is transmitted to the phase modulation means 112, and the beam following the path of the second beam is transmitted to the third mirror M3.

Here, the optical splitter 111 may be composed of an optical fiber coupler, a beam splitter, a geometric phase lens, etc., and transmits the beam to the outside by guiding the free space. It can be implemented in this way. Here, when using a means that can split the beam on the co-axis (in-line), such as a geometric phase lens, it can be split into a first beam and a second beam on the co-axis. Hereinafter, it is assumed that each optical splitter is implemented as a beam splitter.

The phase modulation means 112 shifts the frequency of the first beam and then transmits it to the second mirror (M2). The frequency shifting means, that is, the phase modulating means, can shift the frequency of the first beam by Ω using a frequency generated by a function generator (not shown) and transmit it to the second mirror (M2). Here, the phase modulator may be implemented with various types of modulators that modulate the phase of light according to an electric signal, including an acousto-optic modulator and an electro-optic modulator.

The first beam reflected from the second mirror (M2) is transmitted to the first beam curvature generator (N1). The second beam reflected from the third mirror (M3) is transmitted to the second beam curvature generator (N2). The beam expander can be implemented as a collimator.

The first and second beam curvature generators N1 and N2 receive each beam and generate an enlarged beam having a curvature between negative and positive curvatures, including a collimated beam.

A specific example of implementation of the first beam curvature generator (N1) includes a first lens 113 that converts the first beam reflected from the second mirror (M2) into a spherical wave, and a beam that receives the spherical wave and has a curvature (first curvature As a beam expander having a second lens 115 that generates a beam, the curvature of the beam can be adjusted by adjusting the distance between the first lens 113 and the second lens 115. A specific example of the second beam curvature generator (N2) includes a third lens 114 that converts the second beam reflected from the third mirror (M3) into a spherical wave, and a beam with a curvature (second curvature) that receives the spherical wave. As a beam expander having a fourth lens 116 that generates a beam, the curvature of the beam can be adjusted by adjusting the distance between the third lens 114 and the fourth lens 116.

The first beam curvature generator (N1) converts the first beam into a first curvature beam and transmits it to the interference means (117). That is, the first beam curvature generator N1 generates a second curvature beam by modulating the spatial distribution of the first beam.

The second beam curvature generator (N2) converts the second beam into a first curvature beam and transmits it to the interference means (117). That is, the second beam curvature generator N2 generates the second curvature beam by modulating the spatial distribution of the second beam.

The generated first and second curvature beams interfere with each other while passing through the interference means 117 and are transmitted to the scanning unit 130. The interference means 117 may be implemented as a beam splitter.

The interference means 117 generates a first beam (first curved beam) that has passed through the first beam curvature generator (N1) and a second beam (second curved beam) that has passed through the second beam curvature generator (N2). They overlap and interfere with each other to form scan beams with an interference pattern of a Fresnel zone pattern. The Fresnel annular pattern may represent a beam pattern generated by interference between a first and second curved beam whose curvatures are not completely the same.

In this way, the scan beam generator 110 converts the first beam and the second beam separated from the light source into the first and second curved beams and overlaps them through the interference means 117 to form a scan beam. The scan beam is transmitted to the scan beam splitter 120.

Here, the scan beam generated by the scan beam generator 110 is either linearly polarized at 45 degrees with respect to the horizontal direction of the scan beam splitter 120 (the direction in which the beam is incident on the scan beam splitter in FIG. 1) or is not linearly polarized. Preferably it is a beam.

For this purpose, the laser generates a beam linearly polarized at 45 degrees with respect to the horizontal direction of the scan beam splitter 120, or the laser outputs a linearly polarized beam in a random direction and the linearly polarized direction of the output laser beam is changed using a wave plate. ), a beam polarized at 45 degrees with respect to the horizontal direction of the scan beam splitter 120 can be generated. Of course, when a circularly polarized beam is generated from a laser beam, it can be changed to a linearly polarized beam using a wave plate.

The scan beam splitter 120 splits the incident scan beam into an s-polarized beam and a p-polarized beam and emits the two split polarized beams side by side toward the scan unit 130. That is, the scan beam splitter 120 divides the scan beam received from the scan beam generator 110 into two scan beams (first scan beam: s-polarized beam, second scan beam: p-polarized beam) according to polarization. ) and then output in parallel parallel to each other to deliver it to the scanning unit 130.

This scan beam splitter 120 has the function of splitting the scan beam into an s-polarized beam and a p-polarized beam, the function of adjusting the optical path length between the two split beams to be the same, and the traveling direction of the two split beams. It can be implemented including a function that makes it parallel.

For the first function, it can be implemented through a beam displacer, polarizing prism, or polarized beam splitter (PBS), and for the second and third functions, a combination of multiple mirrors or multiple mirrors can be used. It can be implemented using a combination of mirrors and a polarizing beam splitter (PBS). This will be explained in detail through FIGS. 5A to 5B below.

Next, the configuration of the scan beam splitter shown in FIG. 1 will be described in more detail. The scan beam splitter 120 may be implemented in various structures as follows.

FIGS. 5A to 5H are diagrams illustrating various embodiments of the scan beam splitter shown in FIG. 1.

First, Figure 5a shows the first embodiment of the scan beam splitter. The scan beam splitter 120-1 includes a beam displacer 121a corresponding to a polarization splitter, as shown in the right figure of Figure 5a. It may further include an optical path difference correction unit 122 for correcting the optical path difference between the two divided polarization beams.

The beam displacer 121a separates the scan beam incident through the first side into an s-polarized beam and a p-polarized beam with polarizations orthogonal to each other, and emits them in parallel through the second side. At this time, the beam displacer 121a is made of an anisotropic optical material. Calcite, YVO4, α-BBO, TeO ₂ , etc. may be used as the anisotropic optical material.

In FIG. 5A, among the two polarized beams emitted, a ray whose polarization oscillates in the same direction as the optical axis of the beam displacer 121a (see optical axis indication on the upper surface) is called an ordinary ray, and is perpendicular to the optical axis. A ray whose polarization oscillates in the same direction is called an extra-ordinary ray.

In the case of FIG. 5A, the p-polarized beam emitted from the beam displacer 121a corresponds to a normal ray parallel to the optical axis of the beam displacer 121a, and the s-polarized beam corresponds to an abnormal ray perpendicular to the optical axis.

In this way, when the beam displacer 121a is implemented using an optical material with an anisotropic material crystal structure, it has a birefringent characteristic in which the refractive index changes depending on polarization, so that a beam polarized at 45 degrees or unpolarized is incident and has a phase of 90 degrees. It can be split into two linearly polarized beams (s-polarized beam, p-polarized beam) with a difference.

Therefore, in Figure 5a, using a polarization splitter made only of an anisotropic optical material, two beams, an s-polarized beam and a p-polarized beam, in polarization states perpendicular to the plane including the optical axis, are split in a direction parallel to the incident beam. It can be released.

Here, an optical path difference occurs between the two polarized beams separately emitted from the beam displacer 121a, and the optical path difference correction unit 122 may be used to correct this. At this time, an optical material under the same conditions as the beam displacer 121a can be installed at the position where the normal ray is emitted, and the optical path difference between the two beams can be corrected using this.

Specifically, the optical path difference correction unit 122 is installed on the shorter path of the p-polarized beam among the paths of the s-polarized beam and the p-polarized beam emitted through the second surface of the beam displacer 121a. , It is implemented with the same optical material as the beam displacer 121a, and can compensate for the difference in optical path length between the emitted s-polarized beam and the p-polarized beam.

Here, by adjusting the thickness of the optical material (optical material) constituting the beam displacer 121a, the emission position (inter-beam spacing) of the s-polarized beam and the p-polarized beam can be adjusted, and through this, the beam displacer 121a It is possible to control the displacement value of the emitted beam through .

Next, FIG. 5B is a second embodiment of the scan beam splitter. The scan beam splitter 120-2 shown in FIG. 5B is implemented including a polarizing prism 121b of a Rochon prism structure, and includes a plurality of polarizing prisms 121b. It may further include a displacement control unit and an optical path difference correction unit using a mirror.

The polarizing prism 121b shown in FIG. 5B is implemented as a Rochon prism and is composed of a combination of two triangular prisms whose crystal axes are perpendicular to each other and made of different materials. Here, the polarizing prism 121b divides the scan beam incident through the first surface into an s-polarized beam that travels parallel to the scan beam (incident ray) at the boundary of the two triangular prisms, and the scan beam (incident ray) at a set angle. It is separated into a p-polarized beam that travels with and is emitted through the second side.

In Figure 5b, the crystal axis of the first triangular prism that meets the incident ray is a uniaxial crystal and travels in the same direction as the incident ray, and the crystal axis of the second triangular prism is perpendicular to the crystal axis plane of the first prism. Here, the incident ray is divided into an extra-ordinary ray that is emitted at an angle and an ordinary ray that is emitted parallel to the incident ray, depending on the wavelength of light and the refraction of the material at the boundary between the two triangular prism materials. is separated into

In the case of FIG. 5B, the s-polarized beam emitted parallel to the incident beam corresponds to normal ray, and the p-polarized beam traveling at an angle with the incident beam corresponds to abnormal ray.

Referring to FIG. 5B, the displacement control unit is implemented by including a plurality of mirrors, and may specifically include first and second mirrors M1 and M2. Here, the displacement control unit may further include a position control unit (L2) that adjusts the position of the second mirror (M2) at the rear end of the two mirrors.

The first and second mirrors M1 and M2 are sequentially installed on the path of the p-polarized beam emitted through the second surface of the polarizing prism 121b and change the beam path to change the direction of the p-polarized beam. It serves to adjust the beam to be parallel to the scan beam. That is, the p-polarized beam that has passed through the last second mirror (M2) becomes parallel to the scan beam. In addition, when adjusting the position of the second mirror (M2) through the position adjusting unit (L), the position of the p-polarized beam with respect to the s-polarized beam can be adjusted.

In this way, the displacement control unit plays the role of making the abnormal ray parallel to the normal ray through two mirrors (M1, M2) and adjusts the second mirror (M2) through the position control unit (L2) to adjust the displacement of the beam. It can play a regulating role.

Of course, the present invention is not necessarily limited to the above, and the positions or displacement values of the two beams emitted from the polarizing prism 121b may vary depending on the arrangement and angle of each of the plurality of mirrors M1 to M6 included in FIG. 5b. It can be adjusted.

Here, since the normal ray (s-polarized beam in Fig. 5b) traveling parallel to the incident ray has a shorter optical path than the abnormal ray (p-polarized beam in Fig. 5b), the optical path length is equalized through the optical path difference correction unit. Please correct it properly.

The optical path difference correction unit is installed on the path of the s-polarized beam and the p-polarized beam emitted through the second surface of the polarizing prism 121b, and adjusts the emitted s-polarized beam and the p-polarized beam. It serves to compensate for the difference in optical path length between polarized beams, and for this purpose, it may include third to sixth mirrors (M3 to M6) and a mirror moving unit (L1).

The third to sixth mirrors (M3 to M6) are sequentially installed on the path of the s-polarized beam emitted through the second surface of the polarizing prism 121b to change the beam path, specifically, the s-polarized beam. They are sequentially installed in a 'ㄷ' shape along the beam path, allowing the beam progression path of the s-polarized beam to be changed by 90 degrees.

Through this, the s-polarized beam that has passed through the last sixth mirror (M6) becomes parallel to the incident beam. In addition, in the case of the p-polarized beam separated by the polarizing prism 121b, it becomes parallel to the incident beam through the operation of the displacement control unit including the first and second mirrors M1 and M2 described above, and thus p- The polarized beam and the s-polarized beam ultimately become parallel to each other.

In addition, the mirror moving unit (L1) moves the fourth mirror (M4) and the fifth mirror (M5), which are spaced apart in parallel with the third mirror (M3) and the sixth mirror (M6), as a group, thereby s- The optical path length of the polarized beam can be set to be the same as the optical path length of the p-polarized beam. In the case of Figure 5b, the optical path length of the s-polarized beam can be increased or decreased by adjusting the mirror moving part L1 up and down.

Next, FIG. 5C shows a third embodiment of the scan beam splitter. The scan beam splitter 120-3 shown in FIG. 5C includes a polarizing prism 121c of a Rochon prism structure and further includes a displacement adjustment unit. It can be included.

The polarizing prism 121c shown in FIG. 5C is implemented as a Rochon prism and is composed of a combination of two triangular prisms whose crystal axes are perpendicular to each other and made of different materials.

As in FIG. 5B, the scan beam incident through the first surface of the polarizing prism 121c has an s-polarized beam traveling parallel to the scan beam at the boundary of the two triangular prisms, and a set angle with the scan beam. are separated into p-polarized beams, each exiting through the second side.

At this time, the difference from FIG. 5B is that, as shown in the lower part of FIG. 5C, the polarizing prism 121c is installed (placed) rotated by a set angle (θ/2) based on the center of the boundary surface of the two triangular prisms. . At this time, θ corresponds to the angle difference between the travel directions of the s-polarized beam and the p-polarized beam separately emitted from the center of the boundary surface, as shown in the upper figure.

That is, as shown in the lower part of FIG. 5C, the polarizing prism 121c is arranged in a state rotated by θ/2, which is half of the angle difference θ of the polarized beam. In this case, unlike FIG. 5B, only the displacement adjustment unit is required and the optical path difference correction unit is not required, so it is possible to implement the scan beam splitter 120-3 with a simpler structure.

In this third embodiment, the displacement control unit is sequentially installed on the path of the p-polarized beam emitted through the second surface of the polarizing prism 121c, and first and second mirrors M1 and M2 change the beam path. ), and third and fourth mirrors ( M3,M4). In this way, the travel direction of the p-polarized beam passing through the second mirror M2 and the s-polarized beam passing through the fourth mirror M4 are adjusted to be parallel by the displacement control unit.

In addition, the displacement control unit may further include a position control unit (L) that adjusts the positions of the second mirror (M2) and the fourth mirror (M4) by moving them as a group.

In this way, the displacement control unit makes the abnormal ray (p-polarized beam) parallel to the incident ray through the first and second mirrors (M1, M2) and normalizes the incident ray through the third and fourth mirrors (M3, M4). It serves to make the light beam (s-polarized beam) parallel to the incident light, and also moves the positions of the second mirror (M2) and the fourth mirror (M4) as a group through the position control unit (L). It can additionally play a role in controlling the displacement value of the beam.

As a result, in the case of Figure 5b, six mirrors are used to make the unusual light emitted from the polarizing prism at an angle parallel to the incident light, but in the case of Figure 5c, four mirrors are simply used based on the rotation structure of the polarizing prism. You can achieve the same effect just by using it.

Next, FIG. 5D shows a fourth embodiment of the scan beam splitter. The scan beam splitter 120-4 shown in FIG. 5D includes a polarizing prism 121d of a Senarmont prism structure and adjusts displacement. It may further include a unit and an optical path difference correction unit.

The polarizing prism 121d shown in FIG. 5D is implemented as a Senardmont prism and is composed of a combination of two triangular prisms whose crystal axes are perpendicular to each other and made of different materials.

Here, the polarizing prism 121d is a p-polarized beam that travels parallel to the scan beam at the boundary of the two triangular prisms for the scan beam incident through the first surface, and an s-polarized beam that travels at a set angle with the scan beam. It is separated and emitted through the second side.

In FIG. 5D, the crystal axis of the second triangular prism is perpendicular to the crystal axis of the first triangular prism. At this time, it can be seen that the crystal axis of the second triangular prism has a vertical direction different from the crystal axis of the second triangular prism in FIG. 5B. Here, the incident ray is divided into an ordinary ray, which is emitted at an angle depending on the wavelength of light and the refraction of the material at the boundary between the two triangular prism materials, and an extra-ordinary ray, which is emitted parallel to the incident ray. separated.

In FIG. 5D, the p-polarized beam that is emitted parallel to the incident beam corresponds to an abnormal ray, and the s-polarized beam that travels at an angle to the incident beam corresponds to a normal ray.

In FIG. 5D, the configuration of the displacement control unit including M1, M2, and L2 and the optical path difference correction unit including M3 to M6 and L1 have the same structure and operating principle as those previously shown in FIG. 5B, and thus are related to this. Repeated explanations should be omitted.

Next, Figure 5e shows a fifth embodiment of the scan beam splitter. The scan beam splitter 120-5 shown in Figure 5e includes a polarizing prism 121e of a Senarmont prism structure, and Figure 5c As shown, it may further include a displacement control unit including M1 to M4 and L.

In FIG. 5E, the overall structure of the scan beam splitter is simplified as in FIG. 5C by rotating the polarizing prism shown in FIG. 5D by θ/2. In the case of FIG. 5E, the basic structure and operating principle are the same as those of FIG. 5C except that it is implemented with a Senardmont prism, so repeated description thereof will be omitted.

Next, Figure 5f shows a sixth embodiment of the scan beam splitter. The scan beam splitter 120-6 shown in Figure 5f includes a polarizing prism 121f of a Wollaston prism structure, and in Figure 5c. As shown, it may further include a displacement control unit including M1 to M4 and L.

The polarizing prism 121f is composed of a combination of two triangular prisms whose crystal axes are perpendicular to each other and made of different materials. The scan beam incident through the first surface is adjusted at a set angle with respect to the direction of the scan beam at the boundary surface of the two triangular prisms. It is separated into an s-polarized beam and a p-polarized beam, which proceed symmetrically to each other, and are emitted through the second surface.

In this Wollaston prism structure, if the crystal axis of the first triangular prism that meets the incident ray is perpendicular to the direction of travel of the incident ray, and the crystal axis of the second triangular prism is perpendicular to the first triangular prism, the incident ray is transmitted at the interface between the two materials. Depending on the wavelength and refractive index of the material, it is divided into normal rays and abnormal rays that emit at an angle.

The structure of Figure 5f has the advantage that, unlike Figures 5c or 5e, there is no need to separately rotate the polarizing prism. In addition, in this embodiment of FIG. 5F, the basic structure and operating principle of the displacement control unit implemented including M1 to M4 and L are the same as those of FIG. 5C described above, so detailed description will be omitted. Likewise, the displacement values of the two beams can be adjusted by moving M2 and M4 simultaneously as a group.

Lastly, Figure 5g shows the seventh embodiment of the scan beam splitter, and the scan beam splitter 120-7 shown in Figure 5g includes the first and second polarizing beam splitters (PBS1 and PBS2), and the first to second polarizing beam splitters (PBS1, PBS2). It is implemented including 6 mirrors (M1 to M6). Here, the scan beam splitter 120g may further include a mirror moving unit L1 and a position adjusting unit L2.

The first polarizing beam splitter (PBS1) reflects the s-polarized beam component from the incident scan beam and transmits the p-polarized beam component. The first and second mirrors M1 and M2 are sequentially installed on the path of the s-polarized beam reflected from the first polarizing beam splitter PBS1 to change the beam path by 90 degrees.

The third to sixth mirrors (M3 to M6) are sequentially installed in a 'ㄷ' shape on the path of the p-polarized beam transmitted from the first polarizing beam splitter (PBS1) and change the beam path by 90 degrees.

The second polarizing beam splitter (PBS2) uses the s-polarized beam reflected using the first mirror (M1) and the second mirror (M2) and the p-polarized beam reflected using the third to sixth mirrors (M3 to M6). A polarized beam is incident on each of the first and second surfaces.

The second polarizing beam splitter (PBS2) reflects the s-polarized beam incident on the first side and transmits the p-polarized beam incident on the second side, thereby dividing the reflected s-polarized beam and the transmitted p-polarized beam. Make sure to emit light in a parallel direction through the third side. Of course, the s-polarized beam and p-polarized beam emitted in this way have a direction parallel to the incident ray.

At this time, the mirror moving unit (L1) groups the fourth mirror (M4) and the fifth mirror (M5), which are spaced apart in parallel with the third mirror (M3) and the sixth mirror (M6), and moves them up and down, The optical path length of the p-polarized beam can be set to be the same as the optical path length of the s-polarized beam.

In addition, the position adjuster (L2) can adjust the position of the second mirror (M2) left and right to adjust the displacement of the s-polarized beam emitted through the second polarizing beam splitter (PB2).

The various structures of the scan beam splitter 120 (120-1, 120-2, 120-3, 120-4, 120-5, 120-6, 120-7) shown in FIGS. 5A to 5G according to the present invention. It is applicable to all of the first to fourth embodiments (FIGS. 1, 2, 3, and 4).

Referring again to FIG. 1, two polarized beams (s-polarized beam and p-polarized beam) emitted side by side by the scan beam splitter 120 are transmitted to the scan unit 130.

The beam incident on the scan unit 130 passes through the horizontal scan mirror 131 (hereinafter referred to as x-scan mirror) and the vertical scan mirror 132 (hereinafter referred to as y-scan mirror) to a transmissive object, which is a transmissive object.

At this time, the penetrating body may correspond to various objects having permeability, such as cells, microorganisms, films, transparent objects, or sculptures.

Here, the scan unit 130 includes an x-scan mirror 131 and a y-scan mirror 132 to control the scanning position of the scan beam with respect to the transmitting object. The scan unit 130 uses the scan mirror to control the incident scan beam in the horizontal direction (x direction) and vertical direction (y direction) and transmits it to the transmitting body.

That is, the scan unit 130 receives a scan beam consisting of two polarized beams emitted side by side from the scan beam splitter 120 and projects it onto the transmitting body, and the scanning position of the scan beam with respect to the transmitting body is adjusted in the horizontal and vertical directions. It is controlled and transmitted to the transmitting medium.

In the first embodiment of FIG. 1, the scanning unit 130 uses a mirror scanner. The mirror scanner has an x-scan mirror 131 that scans the object (transmissive body) in the -consists of an x-y scanner with a scanning mirror (132). Of course, in the case of the present invention, the scanning unit is not limited to a mirror scanner, and similar means or other known scanning means may be used. For example, instead of an x-scan mirror and a y-scan mirror, an x-space modulation scanner and a y-space modulation scanner can be replaced.

The scan unit 130 may be operated by receiving a scanning control signal from a scan control unit (not shown) within the signal processing unit 150. The scan control unit (not shown) may generate a scanning control signal to control the scanning position of the scan unit 130. Here, the scanning control signal may include a horizontal scan signal and a vertical scan signal for controlling the x-scan mirror and the y-scan mirror in the horizontal and vertical directions, respectively.

At this time, the horizontal scan signal is a signal for sequentially moving the scan position in the horizontal direction (x-axis direction) by preset distance units, and has a period T for scan movement in arbitrary distance units. The vertical scan signal is a control signal that enables a horizontal scan operation for the next y position when the horizontal scan operation in the x-axis direction for an arbitrary y position is completed, and its period is larger than the horizontal scan signal.

In response to this control signal, the optical axes of the first and second curved beams are rotated as the scan mirror rotates, and the scan beam pattern with the rotated optical axes is projected onto the object (transmitting body). In this way, the scan unit 130 can project an interference beam (scan beam by the scan unit) between the first and second curvature beams onto an object using a scan mirror. Here, of course, the s-wave component and the p-wave component for each curvature beam have a structure in which they are separated vertically by the previous scan beam splitter 120, and the interference beam may also have a structure in which the two polarized waves are separated vertically.

Of course, the scan unit 130 has a structure using a horizontal scan mirror 131 and a vertical scan mirror 132 as shown in FIG. 1, as well as a horizontal scan mirror 331 and a translation stage 332 as shown in FIG. 3, which will be described later. It is also possible to change the scan unit structure using . In addition, in the structure of FIG. 3, when replacing the horizontal scan mirror 331 with a spatial modulation scanner, the scan unit structure can also be changed using a spatial modulation scanner and a translation stage 332. do. Additionally, in the structure of FIG. 1, the horizontal scan mirror 131 and the vertical scan mirror 132 can be replaced with a horizontal spatial modulation scanner and a vertical spatial modulation scanner, respectively.

In this way, the scan unit 130 can be implemented by a combination of a horizontal scan mirror and a vertical scan mirror, a combination of a horizontal scan mirror and a translation stage, and a combination of a spatial light modulator and a translation stage. Other embodiments of the scan unit will be described in detail later with reference to FIG. 3. Here, the table portion on which the object of the translation stage is placed may be made of a transparent material that allows the wavelength of the laser light source to pass through, or may be made of empty space.

The scan beam irradiated by the scan unit 130 to the transparent body passes through the transparent body and is incident on the light detection unit 140. As described above, the scan beam consists of two polarized beams (s-polarized beam and p-polarized beam) split by the scan beam splitter 120.

The light detection unit 140 separates and detects the s-polarized beam and the p-polarized beam from the beam that is projected by the scan unit 130 and then passes through the transmitting body.

Then, the light detection unit 140 transmits the separately detected s-polarized beam and the p-polarized beam to the signal processing unit 150.

Here, as shown in FIG. 1, the light detection unit 140 includes a first concentrator 141a, a first polarizer 142a, a first photodetector 143a, a second concentrator 141b, a second polarizer 142b, and a first concentrator 141b. Includes 2 photodetectors 143b.

The first concentrator 141a is disposed in a direction offset from the optical axis of the beam projected to the transmitting material, and condenses the beam that has transmitted through the transmitting material. This first concentrator 141a may be implemented as a condenser lens.

The first polarizer 142a passes only the s-polarized beam component in the spatially integrated beam through the first concentrator 141a. That is, the first polarizer 142a is disposed behind the first concentrator 141a and transmits only the s-polarized beam component of the beam collected by the first concentrator 141a.

The first photodetector 143a detects the s-polarized beam that has passed through the first polarizer 142a and transmits it to the first signal processing unit 151.

The second concentrator 141b is disposed in a direction that is offset from the optical axis of the beam projected to the transmitting body, but is disposed in a different position from the first concentrator 141a, and condenses the beam that has transmitted through the transmitting body. This second concentrator 141b may be implemented as a condenser lens.

Here, the second concentrator 141b may be arranged symmetrically or asymmetrically with the first concentrator 141a.

The second polarizer 142b passes only the p-polarized beam component in the spatially integrated beam through the second concentrator 141b. That is, the second polarizer 142b is disposed at the rear of the second concentrator 141b and transmits only the p-polarized beam component of the beam collected by the second concentrator 141b.

The second photodetector 143b detects the p-polarized beam that has passed through the second polarizer 142b and transmits it to the second signal processing unit 152.

Of course, the structure of the light detection unit 140 in the present invention is not necessarily limited to FIG. 1, and can also be changed to the structure of FIG. 2, which will be described later. This will be explained in detail later.

The signal processing unit 150 processes signals of the s-polarized beam and the p-polarized beam separately detected by the light detection unit 150 to generate a hologram for the transmitting object.

In the case of an embodiment of the present invention, the scan beam generated by the scan beam generator 110 is split into two polarized beams according to polarization, and then the divided two polarized beams are used as scan beams to scan the object, so the scan beam Compared to the case of scanning the object as is without dividing it, twice the sampling is possible compared to the same time, and a hologram of the object can be created at twice the speed.

Figure 6 is a diagram explaining the operation of a signal processing unit according to an embodiment of the present invention.

Referring to FIGS. 1 and 6 , the signal processing unit 151 includes a first signal processing unit 151, a second signal processing unit 152, and a cross-array signal processing unit 153. The structure and operating principle of the signal processing unit 150 can be equally applied to the systems (FIGS. 2, 3, and 4) according to the second to fourth embodiments of the present invention.

The first signal processor 151 processes the signal of the s-polarized beam detected by the first photodetector 143a and sends it to the cross-array processor 153, and the second signal processor 142 processes the signal of the s-polarized beam detected by the first photodetector 143a. ) The signal of the p-polarized beam detected is processed and sent to the cross-array processing unit 153. These operations may occur simultaneously.

Then, as shown in FIG. 6, the cross-array signal processing unit 150 synthesizes the hologram signal processed in the first signal processing unit 151 and the hologram signal processed in the second signal processing unit 152 by alternating them line by line. Creates a hologram for a transparent object.

According to this, the scan beam generated by the scan beam generator 110 is divided into two beams (s-polarized beam, p-polarized beam) according to polarization, and the two divided polarized beams are simultaneously transmitted to the object (transmitter). By projecting, two lines of signals can be sampled (scanned) at once (unit time), so the number of samples in the y direction is doubled compared to the case of scanning without splitting the scan beam, and the hologram of the object can be produced at twice the speed. Can be produced at high speed.

The operation of the signal processing unit 150 will be described in more detail as follows.

In Figure 1, the first photodetector 143a generates a current signal proportional to the intensity of the concentrated light and transmits it to a two-channel lock-in amplifier, and the two-channel lock-in amplifier demodulates the current signal. In-phase and quadrature-phase hologram information of an object (transmitting body) is extracted as an electrical signal. Of course, a two-channel lock-in amplifier can be implemented by converting it into a digital signal through an analog to digital converter (ADC) and processing it on a computer.

Then, the extracted electrical signal is converted into a digital signal and transmitted to a digital computer. In the digital computer, the digital signals of the real and imaginary parts are synthesized using complex number synthesis and stored according to each scanning position, thereby transmitting the object (transmission). complex holographic information of the body) is recorded. At this time, the recorded hologram is called the first hologram.

In Figure 1, the second photodetector 143b generates a current signal proportional to the intensity of the focused light and transmits it to a two-channel lock-in amplifier, and the two-channel lock-in amplifier demodulates the current signal. In-phase and quadrature-phase hologram information of an object (transmitting body) is extracted as an electrical signal. Of course, a two-channel lock-in amplifier can be implemented by converting it into a digital signal through an analog to digital converter (ADC) and processing it on a computer.

Then, the extracted electrical signal is converted into a digital signal and transmitted to a digital computer. In the digital computer, the digital signals of the real and imaginary parts are synthesized using complex number synthesis and stored according to each scanning position, thereby transmitting the object (transmission). complex holographic information of the body) is recorded. At this time, the recorded hologram is called the second hologram.

The signal processing unit 150 can synthesize the first hologram and the second hologram by alternating them to implement a scan that is twice as long as the scan by the horizontal scan mirror.

Next, a polarization-splitting double scanning holography system for a transmissive material according to a second embodiment of the present invention will be described with reference to FIG. 2A.

As shown in FIG. 2A, the polarization splitting double scanning holography system 200 for a transmitting body according to the second embodiment of the present invention largely includes a scan beam generator 110, a scan beam splitter 120, and a scan unit 130. , includes a light detection unit 240 and a signal processing unit 150. Redundant descriptions of components having the same symbols as those in FIG. 1 will be omitted.

In the case of the second embodiment, the basic structure of the device is the same as that of the first embodiment, but the configuration of the light detection unit 240 is different, and the operating principle is as follows.

In the second embodiment, the light detection unit 240 includes a first light splitter 241, a second light splitter 242, a first concentrator 243a, a second concentrator 243b, a first light detector 244a, and a second light detector 243b. Includes 2 photodetectors 244b.

The first light splitter 241 is disposed on the optical axis of the light projected to the transmitting material and receives the beam that has passed through the transmitting material and reflects it to the outside. This first light splitter 241 can reflect a part of the beam that has passed through the transmitting material and transmit it to the second light splitter 242. The first optical splitter 241 can be implemented as a general beam splitter.

The second light splitter 242 receives the light reflected from the first light splitter 241, transmits the p-polarized beam component of the incident beam, and reflects the s-polarized beam component.

This second light splitter 242 may be implemented as a polarization beam splitter (PBS). In this case, the s-polarized beam is reflected from the second light splitter 242 and transmitted to the first concentrator 243a, and p- The polarized beam passes through and is delivered to the second concentrator 243b.

The first concentrator 243a condenses the s-polarized beam component reflected by the second light splitter 242, and the second concentrator 243b condenses the p-polarized beam component transmitted by the second light splitter 242. do. These first and second concentrators 243a and 243b may be implemented as condensing lenses.

The first photodetector 244a detects a spatially integrated beam (s-polarized beam) through the first concentrator 243a and transmits it to the first signal processor 151 in the signal processor 150. Additionally, the second photodetector 244b detects a spatially integrated beam (p-polarized beam) through the second concentrator 243b and transmits it to the second signal processor 152 in the signal processor 150.

These first and second photodetectors 244a and 244b generate first and second electrical signals, respectively, in proportion to the intensity of transmitted light. The first photodetector 244a transmits the first electrical signal to the first signal processor 151, and the second photodetector 244b transmits the second electrical signal to the second signal processor 152.

Here, of course, the second beam splitter 242 can be replaced with a beam splitter (BS) instead of the polarization beam splitter (PBS), and in this case, the role of the polarization beam splitter (PBS) is through the combination of the beam splitter (BS) and the two polarizers. can be performed. This is explained through Figure 2b.

In Figure 2b, the light detection unit 240 includes a first light splitter 241, a second light splitter 242, a first polarizer 245a, a second polarizer 245b, a first concentrator 243a, and a second concentrator ( 243b), a first photodetector 244a, and a second photodetector 244b.

In FIG. 2B, reference numerals 241, 244a, and 244b perform the same functions as those in FIG. 2A, so duplicate description thereof will be omitted.

In Figure 2b, the second light splitter 242 is a BS (Beam Splitter), which receives the light reflected from the first light splitter 241 and splits it by transmitting part of the incident beam and reflecting part of it.

The first polarizer 245a receives the beam reflected from the second light splitter 242 and passes only the s-polarized beam component, and the second polarizer 245b receives the beam transmitted from the second light splitter 242 and passes only the s-polarized beam component. Only the polarized beam component passes through.

The first concentrator 243a condenses the s-polarized beam component that has passed through the first polarizer 245a, and the second concentrator 243b condenses the p-polarized beam component that has passed through the second polarizer 245b. The subsequent operations of the first and second photo detectors 244a and 244b are the same as those described above.

Next, a polarization-splitting double scanning holography system for a transmissive material according to a third embodiment of the present invention will be described with reference to FIG. 3.

As shown in FIG. 3, the polarization splitting double scanning holography system 300 for a transmitting body according to the third embodiment of the present invention largely includes a scan beam generator 110, a scan beam splitter 120, and a scan unit 330. , includes a light detection unit 140 and a signal processing unit 150. Redundant descriptions of components having the same symbols as those in FIG. 1 will be omitted.

In this third embodiment, the basic structure of the device is the same as the first embodiment, but the configuration of the scan unit 330 is different, and the operating principle is as follows.

In FIG. 3, the scan unit 330 is installed at the rear end of the scan beam splitter 120 to control the scanning position of the scan beam with respect to the transmitting object in the horizontal and vertical directions and detects the scan incident from the scan beam splitter 120. A scanning mirror 331 that controls the beam in the horizontal direction (x direction) and transmits it to the transmitting body, and a translation stage 332 that moves the transmitting body in the vertical direction (y direction) at the rear end of the transmitting body. Includes.

That is, in the case of FIG. 3, a scan beam including two polarized beams emitted from the scan beam splitter 330 is incident on the scan unit 330. The beam incident on the scanning unit 330 is transmitted to the transmitting body through the scanning mirror 331. Here, the scan mirror 331 scans the transparent body in the x-direction, and the translation stage 332 located at the rear of the transparent body scans the transparent body in the y-direction.

The scan mirror 331 controls the scan beam incident from the scan beam splitter 120 in the horizontal direction and transmits it to the transmitting body. The translation stage 332 is installed at the rear of the transmissive body and moves the transmissive body receiving the scan beam directly in the vertical direction, enabling y-direction scanning of the transmissive body through the scan beam.

This translation stage 332 corresponds to a moving objective plate in which the objective plate on which the transmitting material is placed is movable in the y-axis direction. Although this translation stage 332 is physically separated from the scan mirror 331, it is a means of controlling the scanning position of the beam with respect to the transmitting object, so it is a component of the scan unit 330 together with the scan mirror 331. It is included as

In this way, the scan unit 330 uses the scan mirror 331 and the translation stage 332 to control the scan beam in the horizontal direction (x direction) and the vertical direction (y direction) based on the transmitting object.

In this third embodiment, the scanning unit 330 uses a mirror scanner. The mirror scanner has an x-scan mirror 321 that scans the transmitting object in the x direction (left and right directions) around the y axis. In the case of the present invention, the scanning unit is not limited to a mirror scanner, and similar means or other known scanning means may be used.

Like the first embodiment, the scan unit 330 may be operated by receiving a scanning control signal from a scan control unit (not shown) within the signal processing unit 150. The scan control unit (not shown) generates a scanning control signal to control the scanning position of the scan unit 330. Here, the scanning control signal may include a horizontal scan signal and a vertical scan signal for controlling the scan mirror 331 and the translation stage 332 in the horizontal and vertical directions, respectively.

At this time, the horizontal scan signal is a signal for sequentially moving the scan position in the horizontal direction (x-axis direction) by preset distance units, and has a period T for scan movement in arbitrary distance units. The vertical scan signal, which is a signal that moves the translation stage 332 in the vertical direction, is a translation that enables a horizontal scan operation for the next y position when the horizontal scan operation in the x-axis direction for an arbitrary y position is completed. As a stage control signal, its period is larger than that of the horizontal scan signal.

Of course, in this structure of FIG. 3, the scan mirror 331 can be replaced with a spatial modulation scanner. In this case, the scanning unit 330 may be implemented including a spatial modulation scanner 331 and a translation stage 332. Hereinafter, for convenience of explanation, the spatial modulation scanner will be described by assigning code 331.

In this case, the beam incident on the scanning unit 330 is transmitted to the transmitting body through the spatial modulation scanner 331. Here, the spatial modulation scanner 331 scans the transparent body in the x-direction, and the translation stage 332 located at the rear of the transparent body scans the transparent body in the y-direction.

That is, the spatial modulation scanner 331 controls the scan beam incident from the scan beam splitter 120 in the horizontal direction and transmits it to the transmitting body, and the translation stage 132 receives the scan beam incident at the rear end of the transmitting body. By directly moving the transmitting object in the vertical direction, y-direction scanning of the transmitting object through a scan beam is also possible.

In this way, the scan unit 330 uses the spatial modulation scanner 331 and the translation stage 332 to control the scan beam in the horizontal direction (x direction) and vertical direction (y direction) based on the transmitting object. It may be possible.

At this time, the spatial modulation scanner modulates the spatial distribution of the incident beam and operates to scan the beam in a specific direction.

A spatial modulation scanner can be implemented with a spatial light modulator (SLM), a digital micromirror device (DMD), an acoustic-optic deflector, etc. Accordingly, the spatial modulation scanner is configured to include one type of spatial modulation scanner selected from SLM, DMD, and acoustic-optical deflector.

Figure 7 is a diagram explaining the operating principle of a spatial modulation scanner. The spatial modulation scanner is an element that can replace the scan mirror 131 in the scan unit 330 of FIG. 3 and corresponds to a horizontal spatial modulation scanner that scans an object in the x direction. Figure 7 explains the principle of this horizontal spatial modulation scanner.

As shown in FIG. 7, in a spatial modulation scanner, the spacing of the grating pattern (P) changes sequentially over time according to the input of a scanning control signal by a scan control unit (not shown), thereby controlling the scan beam in the horizontal direction. can do.

In other words, the spacing of the grating pattern formed in the horizontal spatial modulation scanner by the electrical signal is adjusted over time, allowing the incident beam to move in the x-direction. In general, as the spacing between patterns becomes narrower, the light is bent at a greater angle.

Therefore, in the case of a horizontal spatial modulation scanner, the scan beam can move in the horizontal direction by adjusting the size of the gap between the grating patterns (P) formed along the horizontal direction according to the scanning control signal. In this way, in the case of a spatial modulation scanner, the direction of the incident beam is electrically controlled.

In this case as well, the scan unit 330 operates by receiving a scanning control signal from the scan control unit (not shown) in the signal processing unit 150. Here, the scanning control signal for the spatial modulation scanner 331 may include a signal that sequentially changes the spacing size of the grating pattern over time. Additionally, the scanning control signal for the translation stage 332 may include a signal that moves the translation stage 332 in the vertical direction over time.

Additionally, the scanning control signal may include a horizontal scan signal and a vertical scan signal for controlling the scan beam in the horizontal and vertical directions, respectively.

The horizontal scan signal for controlling the scan beam incident on the spatial modulation scanner 331 in the horizontal direction is a signal for sequentially moving the scan position in the horizontal direction (x-axis direction) by preset distance units, and is a random distance unit. It has a period T for scan movement. The vertical scan signal, which is a signal that moves the translation stage 332 in the vertical direction, is a translation that enables a horizontal scan operation for the next y position when the horizontal scan operation in the x-axis direction for an arbitrary y position is completed. As a stage control signal, its period is larger than that of the horizontal scan signal.

Here, both the horizontal scan mirror 131 and the vertical scan mirror 132 of FIG. 1 can be replaced with a spatial modulation scanner. In this case, the scanning unit 120 is a horizontal spatial modulation scanner (x-space) that scans the object in the x direction. It can be implemented as an x-y scanner with a modulation scanner) and a vertical spatial modulation scanner (y-space modulation scanner) scanning in the y direction.

Figure 8 is a diagram explaining the operating principle of the horizontal and vertical spatial modulation scanner. As shown in FIG. 8, in a vertical or horizontal spatial modulation scanner, the spacing of the grating pattern (P) changes sequentially over time according to the input of a scanning control signal by a scan control unit (not shown), thereby directing the scan beam vertically. Or control in the horizontal direction.

In other words, the spacing of the grating pattern formed in the spatial modulation scanner by the electrical signal is adjusted over time, allowing the incident beam to move in the x-direction. In general, as the spacing between patterns becomes narrower, the light is bent at a greater angle.

For example, in the case of a horizontal spatial modulation scanner, the scan beam can move in the horizontal direction by adjusting the size of the gap between the grating patterns (P) formed along the horizontal direction according to the scanning control signal. In the case of a vertical spatial modulation scanner, the scan beam can move in the vertical direction by adjusting the size of the gap between the grating patterns (P) formed along the vertical direction according to the scanning control signal.

In this way, in the case of a spatial modulation scanner, the direction of the incident beam is electrically controlled.

Next, a polarization-splitting double scanning holography system for a transmissive material according to a fourth embodiment of the present invention will be described with reference to FIG. 4A.

As shown in FIG. 4A, the polarization splitting double scanning holography system 400 for a transmitting body according to the fourth embodiment of the present invention largely includes a scan beam generator 110, a scan beam splitter 120, and a scan unit 330. , includes a light detection unit 240 and a signal processing unit 150. Redundant descriptions of components having the same symbols as those in FIG. 1 will be omitted.

In the case of the fourth embodiment, the basic structure of the device is the same as that of the first embodiment, but the configurations of the scanning unit 330 and the light detection unit 240 are different. Here, the operation of the scanning unit 330 has been described in detail with reference to FIG. 3, and the operation of the light detection unit 240 has been described in detail with reference to FIG. 2A, so duplicate descriptions will be omitted.

Meanwhile, the first to fourth embodiments of the present invention may additionally include a circular polarization conversion unit. The role of this circular polarization converter can be implemented through the configuration of λ/4 wave plates (WP; WP1, WP2) inserted with dotted lines in FIGS. 1 and 2A, respectively. In the case of FIGS. 3 and 4A, a circular polarization conversion unit like that of FIGS. 1 and 2A may also be applied.

1 as a representative example, the case of FIG. 1 includes a first λ/4 wave plate (WP1) and a second λ/4 wave plate (WP2).

At this time, the first λ/4 wave plate WP1 is installed between the scan unit 130 and the transmitting material to convert the scan beam into circularly polarized light and project it to the transmitting material. The second λ/4 wave plate WP2 is installed between the transmitter and the light detection unit 140 to convert the circularly polarized beam back into linearly polarized light and provide it to the light detection unit 140. Here, specifically, the second λ/4 wave plate WP2 is separately installed between the transmitting body and the first light collecting part 141a, and between the transmitting body and the second light collecting part 141b.

As in the embodiment of the present invention, a method of splitting a scan beam into two according to polarization and individually detecting beams corresponding to the polarization is to separate a first hologram and a second hologram in the case of an object whose reflection or transmittance depends on polarization. There may be differences depending on polarization. In order to eliminate this polarization difference, a wave plate is placed between the scan unit 130 and the object (transmitter) to convert the polarization of the scan beam into circular polarization and project it onto the object, and the object (transmitter) and the concentrator 141 By using a method of converting back to linearly polarized light by placing a wave plate between them, the first and second holograms can be recorded regardless of the polarization dependence of the object.

In addition, in the case of FIG. 2A, the first λ/4 wave plate WP1 is installed in the path between the scan unit 130 and the transmitting body, more specifically, between the scan unit 130 and the first optical splitter 241. In addition, the second λ/4 wave plate WP2 can be installed between the transmitter and the light detection unit 240, and more specifically, between the first and second light splitters 241 and 242 on the corresponding path. there is. Of course, various modifications may exist in the installation location of the wave plate.

According to the present invention, it is possible to obtain a hologram for a transparent object at ultra-high speed, faster than the scanning speed of a scan mirror.

The present invention has been described with reference to the embodiments shown in the drawings, but these are merely illustrative, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true scope of technical protection of the present invention should be determined by the technical spirit of the attached patent claims.

Claims (20)

1. After modulating the phase of the first beam divided from the light source and converting it into a first curvature beam through the first beam curvature generator and converting the second beam into a second curvature beam through the second beam curvature generator, the first and a scan beam generator that forms a scan beam by interfering with the second curvature beam;

   a scan beam splitter that splits the scan beam into an s-polarized beam and a p-polarized beam and emits the two split polarized beams side by side;

   A scan in which a scan beam consisting of two polarized beams emitted side by side is incident from the scan beam splitter and projected onto a transmitting body, and the scanning position of the scan beam with respect to the transmitting body is controlled in the horizontal and vertical directions and transmitted to the transmitting body. wealth;

   a light detection unit that separates and detects the s-polarized beam and the p-polarized beam from the beam that has transmitted through the transmitting body; and

   A polarization-splitting double scanning holography system for a transmitting object, comprising a signal processing unit that processes signals of the separately detected s-polarized beam and the p-polarized beam to generate a hologram for the transmitting object.
2. In claim 1,

   The light detection unit,

   a first concentrator disposed in a direction biased to the optical axis of the beam projected to the transmitting body and concentrating the beam that has passed through the transmitting body;

   a first polarizer that passes only the s-polarized beam component in the spatially integrated beam through the first concentrator;

   a first photodetector that detects the s-polarized beam that has passed through the first polarizer;

   a second concentrator disposed in a direction biased to the optical axis of the beam projected to the transmitting body and at a different position from the first concentrator, and concentrating the beam that has transmitted through the transmitting body;

   a second polarizer that passes only the p-polarized beam component of the spatially integrated beam through the second concentrator; and

   A polarization-splitting double scanning holography system for a transmitting body including a second photodetector for detecting a p-polarized beam that has passed through the second polarizer.
3. In claim 1,

   The light detection unit,

   a first light splitter disposed on the optical axis of the light projected to the transmitting body and receiving the beam passing through the transmitting body and reflecting it to the outside;

   a second light splitter that receives the light reflected from the first light splitter and transmits the p-polarized beam component and reflects the s-polarized beam component of the incident beam;

   a first concentrator that focuses the s-polarized beam component reflected by the second light splitter;

   a second concentrator for concentrating the p-polarized beam component transmitted from the second light splitter;

   a first photodetector that detects a spatially integrated beam through the first concentrator; and

   A polarization-splitting double scanning holography system for a transmitting body including a second photodetector that detects a spatially integrated beam through the second concentrator.
4. In claim 1,

   The light detection unit,

   a first light splitter disposed on the optical axis of the light projected to the transmitting body and receiving the beam passing through the transmitting body and reflecting it to the outside;

   a second light splitter that receives the light reflected from the first light splitter, transmits part of the incident beam, and reflects part of the incident beam;

   a first polarizer that receives the beam reflected from the second light splitter and passes only the s-polarized beam component;

   a second polarizer that receives the beam transmitted from the second light splitter and passes only the p-polarized beam component;

   a first concentrator that focuses the s-polarized beam component that has passed through the first polarizer;

   a second concentrator that focuses the p-polarized beam component that has passed through the second polarizer;

   a first photodetector that detects a spatially integrated beam through the first concentrator; and

   A polarization-splitting double scanning holography system including a second photodetector that detects a spatially integrated beam through the second concentrator.
5. The method of any one of claims 2 to 4,

   The signal processing unit,

   a first signal processor that processes the signal of the s-polarized beam detected by the first photodetector;

   a second signal processor that processes the signal of the p-polarized beam detected by the second photodetector; and

   A transmissive body including a cross-array signal processing unit that generates a hologram for the transmissive body by synthesizing the hologram signal processed in the first signal processing unit and the hologram signal processed in the second signal processing unit by alternating line by line. Polarization splitting double scanning holography system.
6. In claim 1,

   The scan beam splitter,

   A beam displacer is made of an anisotropic optical material and separates the scan beam incident through the first side into an s-polarized beam and a p-polarized beam with polarizations orthogonal to each other and emits them in parallel through the second side. A polarization-splitting double scanning holography system for a transmissive material including.
7. In claim 6,

   The scan beam splitter,

   It is installed on the path of the shorter p-polarized beam among the paths of the s-polarized beam and the p-polarized beam emitted through the second surface, and is implemented with the same material as the beam displacer, so that the emitted s-polarized beam A polarization-splitting double scanning holography system for a transmitting body, further comprising an optical path difference correction unit that compensates for the difference in optical path length between the and p-polarized beams.
8. In claim 1,

   The scan beam splitter,

   It consists of a combination of two triangular prisms whose crystal axes are perpendicular to each other and are made of different materials, and a first polarized beam and a scan beam that propagates the scan beam incident through the first surface parallel to the scan beam at the boundary surface of the two triangular prisms. It includes a polarizing prism that separates the beam into a second polarized beam traveling at a set angle and emits it through the second surface,

   If the first polarized beam is an s-polarized beam, the second polarized beam is a p-polarized beam, and if the first polarized beam is a p-polarized beam, the second polarized beam is an s-polarized beam. Polarization splitting for a transmitter Double scanning holography system.
9. In claim 8,

   The scan beam splitter,

   Displacement that adjusts the direction of travel of the second polarized beam to be parallel to the scan beam through first and second mirrors that are sequentially installed on the path of the second polarized beam emitted through the second surface and change the beam path. control unit; and

   It is installed on the path of the shorter first polarized beam among the paths of the first and second polarized beams emitted through the second surface, and compensates for the difference in optical path length between the first and second polarized beams emitted. A polarization splitting double scanning holography system for a transmitting body further comprising an optical path difference correction unit.
10. In claim 9,

    The optical path difference correction unit,

    Third to sixth mirrors that are sequentially installed on the path of the first polarized beam emitted through the second surface to change the beam path, and

    A polarization splitting double scanning holography system for a transmitting body including a mirror moving unit that compensates for the difference in the optical path length while moving the fourth and fifth mirrors arranged in parallel and spaced apart from the third and sixth mirrors as a group.
11. In claim 8,

    The polarizing prism is,

    Polarization-splitting double scanning holography system for transmitters structured as Rochon prisms or Senarmont prisms.
12. In claim 8,

    The polarizing prism is installed rotated by a set angle based on the center of the boundary surface,

    The setting angle is,

    A polarization-splitting double scanning holography system for a transmitter whose θ/2 is half of the angular difference (θ) between the travel directions of the first and second polarized beams separately emitted from the center of the boundary surface.
13. In claim 12,

    The scan beam splitter,

    First and second mirrors are sequentially installed on the path of the second polarized beam emitted through the second surface to change the beam path, and sequentially installed on the path of the first polarized beam emitted through the second surface. It is installed to change the beam path and further includes a displacement control unit including third and fourth mirrors installed symmetrically with the first and second mirrors,

    A polarization splitting double scanning holography system for a transmitting body in which the travel directions of the second polarized beam that has passed through the second mirror and the first polarized beam that has passed through the fourth mirror are adjusted to be parallel by the displacement control unit.
14. In claim 1,

    The scan beam splitter,

    It is composed of a combination of two triangular prisms whose crystal axes are perpendicular to each other and made of different materials, and the scan beam incident through the first surface is symmetrically directed at the boundary surface of the two triangular prisms at a set angle with respect to the direction of the scan beam. A polarization splitting double scanning holography system for a transmitter including a polarizing prism of a Wollaston prism structure that separates the s-polarized beam and the p-polarized beam and emits them through a second surface.
15. In claim 14,

    The scan beam splitter,

    First and second mirrors sequentially installed on the path of the p-polarized beam emitted through the second surface to change the beam path, and sequentially installed on the path of the s-polarized beam emitted through the second surface. It is installed to change the beam path and further includes a displacement control unit including third and fourth mirrors installed symmetrically with the first and second mirrors,

    A polarization splitting double scanning holography system for a transmitting body in which the travel directions of the p-polarized beam that has passed through the second mirror and the s-polarized beam that has passed through the fourth mirror are adjusted to be parallel by the displacement control unit.
16. In claim 1,

    The scan beam splitter,

    a first polarizing beam splitter that reflects the s-polarized beam component from the incident scan beam and transmits the p-polarized beam component;

    first and second mirrors sequentially installed on the path of the s-polarized beam reflected from the first polarizing beam splitter to change the beam path by 90 degrees;

    third to sixth mirrors sequentially installed on the path of the p-polarized beam transmitted from the first polarizing beam splitter to change the beam path by 90 degrees; and

    An s-polarized beam that has passed through the second mirror and a p-polarized beam that has passed through the sixth mirror are incident on the first and second surfaces, respectively, and the s-polarized beam reflected after incident on the first face and the A polarization splitting double scanning holography system for a transmitter including a second polarization beam splitter that outputs the p-polarized beam transmitted after incident on the second side in a parallel direction through the third side.
17. In claim 1,

    The scanning unit,

    Polarization-splitting double scanning holography for a transmitting body that includes a horizontal scanning mirror and a vertical scanning mirror to control the scanning position of the scan beam with respect to the transmitting body, and controls the incident scan beam in the horizontal and vertical directions and transmits it to the transmitting body. system.
18. In claim 1,

    The scanning unit,

    A scanning mirror that controls the scan beam incident from the scan beam splitter in the horizontal direction and transmits it to the transmitting body so as to control the scanning position of the scan beam with respect to the transmitting body in the horizontal and vertical directions, and at the rear end of the transmitting body A polarization-splitting double scanning holography system for a transmissive body including a translation stage that moves the transmissive body in a vertical direction.
19. In claim 1,

    The scanning unit,

    a spatial modulation scanner that controls the scan beam incident from the scan beam splitter in the horizontal direction and transmits it to the transmitting body so as to control the scanning position of the scan beam with respect to the transmitting body in the horizontal and vertical directions; A polarization-splitting double scanning holography system for a transmitting body including a translation stage that moves the transmitting body in the vertical direction at the rear end of the transmitting body.
20. In claim 1,

    The scanning unit,

    A horizontal space including a vertical scanner and a horizontal scanner for controlling the scanning position of the scan beam relative to the object in the horizontal and vertical directions, and controlling the scan beam incident from the scan beam splitter in the horizontal direction to transmit it to the object. A polarization-splitting double scanning holography system including a spatial modulation scanner and a vertical spatial modulation scanner that controls the scan beam in the vertical direction and delivers it to an object.

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