WO2014061350A1

WO2014061350A1 - Optical component, terahertz wave module, and optical component manufacturing method

Info

Publication number: WO2014061350A1
Application number: PCT/JP2013/072888
Authority: WO
Inventors: 清水　誠; 石橋　忠夫; 和宏丸山; 小林　賢二; 長峰　勝; 五神　真; 邦昭小西
Original assignee: Ｎｔｔエレクトロニクス株式会社; 株式会社長峰製作所
Priority date: 2012-10-15
Filing date: 2013-08-27
Publication date: 2014-04-24
Also published as: JP2014081448A

Abstract

　The purpose of the present invention is to provide: an optical component made from a material through which terahertz waves can pass, which is not susceptible to damage, and which is easily manufactured; a terahertz wave module equipped with the same; and a method for manufacturing said optical component.　This optical component is formed from alumina, and terahertz electromagnetic waves pass into the alumina. Alumina allows terahertz waves to pass therethrough. Furthermore, because alumina components are high-strength, and can be molded by injection molding or powder molding, the abovementioned issues are resolved.

Description

Optical component, terahertz wave module, and optical component manufacturing method

The present invention relates to a terahertz wave optical component, a terahertz wave module mounted with the same, and a method of manufacturing the optical component.

Conventionally, as lenses for terahertz waves (herein, electromagnetic waves having a frequency of 0.1 to 10 terahertz), plastic lenses represented by polyethylene, cycloolefin, and polymethylpentene, or high resistance silicon single crystal materials Lenses are used. In particular, as a lens mounted on a module using a photoconductive antenna for terahertz wave generation or reception, a photo mixer, and a Schottky barrier diode, a chip for terahertz wave generation or terahertz wave reception is a semiconductor with a high refractive index. For some reason, silicon single crystal lenses are used rather than plastic lenses.

Patent Document 1 describes a photo mixer module in which an antenna integrated PD element is mounted on the center of a silicon spherical lens (hemispherical lens) as a module to which such terahertz waves can be applied. The photo mixer module can generate a millimeter wave or sub-millimeter wave (terahertz wave band) signal.

FIG. 1 is a view of a photo mixer module using a silicon spherical lens disclosed in Patent Document 1. As shown in FIG. The reference numeral 1-1 denotes a housing of the module, 1-2 denotes a silicon spherical lens (hemispherical lens), 1-3 denotes an antenna integrated light receiving element, and 1-5 to 1-8 denote reflecting mirrors and lenses of an optical system. By inputting an optical signal through the optical fiber 1-9, it is possible to extract a millimeter wave or sub-millimeter wave beam from the silicon spherical lens 1-2. The antenna integrated light receiving element 1-3 is an element of end surface incidence type.

Representative devices using conversion of an optical signal to a terahertz wave include (1) a photoconductive antenna semiconductor chip, and (2) a photodiode semiconductor chip and a terahertz wave antenna formed on the photodiode semiconductor chip. Non-Patent Documents 1 to 3 describe this operation.

In addition, as a device for generating terahertz waves directly from an electrical signal, there is an RTD (resonant tunneling diode) or a quantum cascade laser. This operation is described in Non-Patent Document 3.

As a device used for terahertz wave reception, there is a method using a Schottky barrier diode or a photoconductive antenna. Non-Patent Document 3 also describes these devices.

JP 2005-64987 A

The optical component for terahertz wave transmission installed in a module for transmitting and receiving terahertz waves is required to have a high refractive index as described above, and at present, a high resistance silicon single crystal is the only material. However, it is a problem (first problem) that breakage of the material is easily generated during lens processing and when the lens is fixed to the holder due to being a single crystal material. In addition, the lens surface can only be formed by cutting or polishing, and for this reason, forming a surface shape other than a spherical surface requires a high-level processing technology and can not realize a low-cost aspheric lens (second subject ) Also.

First, the first problem will be described. As described above, since the Si lens is a crystalline material, the processing method must be performed by cutting or polishing. It was impossible to avoid the formation of minute cracks on the surface by this processing, and it was inevitable that the possibility of breakage due to the growth of such minute cracks was avoided. In addition, when mounting as a module, a crack of the lens may grow to cause breakage due to a stress applied by adhesion for fixing the lens, and thus, improvement in reliability is required.

Next, the second problem will be described. In the case of a spherical lens, there is a phenomenon (aberration) in which light passing through the center of the lens and light passing through the periphery of the lens shift the focal position (aberration), but a lens generally used to solve this aberration problem is an aspheric lens.

FIG. 2 is a view showing the light beam of the terahertz wave beam emitted when the point oscillation source of the terahertz wave is disposed on the planar side of the Si hemispherical lens. Point oscillation sources are arranged with three types of offsets on the central axis from the central position of the spherical lens. As shown in FIG. 2B, when the terahertz wave point oscillation source is arranged at a position given a specific offset, the terahertz wave beam emitted from the lens surface is emitted without spherical aberration. On the other hand, in the arrangement with a larger offset (FIG. 2C) or the arrangement with a smaller offset (FIG. 2A), the focal positions of the ray passing through the lens central portion and the ray passing through the lens peripheral portion are largely different (spherical surface aberration). The problem with using a spherical lens is that it is not in principle a collimated beam at offset positions where spherical aberration is eliminated. Therefore, in a module using a spherical lens, the terahertz wave point oscillation source is disposed at an offset position where there is no spherical aberration, and another lens or an off-axis parabolic mirror is disposed on the optical axis of the output beam of the module. A method of collimating is taken.

In order to avoid such spherical aberration, it is necessary to make the lens shape aspheric. In the case of manufacturing by cutting or polishing, this aspherical shape requires a very advanced processing technology, and there is a problem that mass productivity is lacking. In the case of amorphous glass, an aspheric lens is manufactured by a method excellent in mass productivity by molding (injection molding) method, but in the case of a silicon (Si) lens, it is a Si single crystal material. Because of this, molding was impossible.

Accordingly, the present invention has been made in view of the above two problems, and is an optical component of a material that can transmit terahertz waves, is less likely to be damaged, and is easy to manufacture, a module for terahertz waves including the same, and An object of the present invention is to provide a method of manufacturing the optical component.

In order to achieve the above object, an optical component according to the present invention is made of alumina.

Specifically, the optical component according to the present invention is an optical component which is formed of alumina and through which the terahertz electromagnetic wave passes in the alumina. Alumina transmits terahertz waves. The alumina parts have high strength and can be molded by injection molding or powder molding, so that the first and second problems described above can be solved. Therefore, the present invention can provide an optical component of a material that can transmit terahertz waves, is less likely to be damaged, and is easy to manufacture.

The optical component according to the present invention is characterized in that at least a part of the surface has an aspheric lens shape. Since the material is alumina, an aspheric lens shape can be formed on a part of the optical component by injection molding or powder molding as described above. Therefore, the present invention can also solve the problem of the spherical aberration existing in the Si lens for terahertz waves.

The optical component according to the present invention may be a cylindrical lens, a prism, a corner cube, a beam splitter, a mirror, a window or a microlens array.

A terahertz wave module according to the present invention includes the optical component and an electromagnetic wave emitting unit that emits a terahertz electromagnetic wave into the alumina of the optical component.

Another terahertz wave module according to the present invention includes the optical component and an electromagnetic wave receiving unit that receives a terahertz electromagnetic wave from within the alumina of the optical component.

The present module uses a conventional technique for chips for generating or receiving terahertz waves, but includes an optical component formed of alumina as an optical component for shaping terahertz waves emitted or incident from the chips. The strength of the optical component is high, the reliability of the module can be enhanced, and the manufacturing is easy, so that the cost of the module can be reduced.

Therefore, the present invention can provide a terahertz wave module provided with an optical component of a material that can transmit terahertz waves, is less likely to be damaged, and is easy to manufacture.

The optical component manufacturing method according to the present invention is an optical component manufacturing method for manufacturing the optical component, comprising: an injection molding step of filling and molding alumina in the mold cavity using a mold having a desired shape; And sintering the alumina molded body after the injection molding step to form the optical component.

Another optical component manufacturing method according to the present invention is an optical component manufacturing method for manufacturing the optical component, wherein a powder having a mold of a desired shape is filled with alumina powder in the mold cavity and compacted. And a sintering step of sintering the alumina molded body after the powder molding step to form the optical component.

The optical component according to the present invention can be mass-produced by injection molding or powder molding using alumina as a raw material. In addition, it is possible to produce any surface-shaped optical component including an aspheric surface by changing the mold shape. Therefore, the present invention can provide a method of manufacturing an optical component of a material that can transmit terahertz waves, is less likely to be damaged, and is easy to manufacture.

According to the present invention, it is possible to provide an optical component of a material that can transmit terahertz waves, is less likely to be damaged and is easy to manufacture, a module for terahertz waves provided with the same, and a method of manufacturing the optical components.

It is a figure explaining the structure of the module for terahertz waves using a silicon spherical lens. When the point oscillation source of the terahertz wave is disposed on the plane side of the Si hemispherical lens, it is a diagram showing the light beam of the terahertz wave beam emitted. It is a figure explaining the optical component manufacturing method which concerns on this invention. It is a figure explaining the result of having evaluated the refractive index and absorption coefficient of the optical component which concerns on this invention. It is a design value of the optical component (aspheric lens) concerning the present invention. It is a figure explaining the composition of the module for terahertz waves concerning the present invention. It is a figure explaining the result of having measured the intensity of the terahertz wave outputted from the module for terahertz waves concerning the present invention. It is a two-sided view explaining the optical component which concerns on this invention. It is a perspective view explaining the optical component concerning the present invention. It is a figure explaining the terahertz wave which injects into the optical component which concerns on this invention. It is a two-sided view explaining the optical component which concerns on this invention.

Hereinafter, embodiments of the present invention will be described using the drawings. The embodiments described below are examples of implementation of the present invention, and the present invention is not limited to the following embodiments. These implementation examples are merely illustrative, and the present invention can be implemented in various modifications and improvements based on the knowledge of those skilled in the art. In the present specification and drawings, components having the same reference numerals denote the same components.

Embodiment 1
In the present embodiment, the results of evaluating the complex refractive index of the alumina plate manufactured by injection molding and powder molding will be described below.

The method for producing an alumina plate material to be evaluated is an injection molding process in which alumina is filled and molded in the mold cavity using a mold having a desired shape, and the alumina molded body after the injection molding process is sintered to And an optical component.

A brief description will be given of plate material production by injection molding. FIG. 3 is a view briefly explaining a plate manufacturing method. Using the upper mold (3-1) in which the shape of the plate is cut, and the lower mold (3-2) in which the raw material feeding passage (3-3) and the raw material discharging passage (3-4) are formed With the mold closely adhered, a mixture of alumina and a molding binder is fed from the raw material feeding path (3-3) and filled in the mold cavity. At this time, a raw material discharge passage (3-4) is provided at a position opposite to the input portion in order to sufficiently fill the space. The alumina material thus molded is obtained as an alumina molded body (3-5) shown in FIG. 3 by heat treatment for degreasing and firing at a higher temperature after being taken out of the mold.

The plate-like alumina compact manufactured by the said injection molding is 100% alumina. FIG. 4 shows the results of evaluating the refractive index and the absorption coefficient in the terahertz wave region of the plate-like alumina molded body. The measurement range is 0.5 THz to 2.5 THz. In the measurement range, the refractive index of the alumina molded body is approximately 3.1, which is slightly lower than the refractive index 3.4 of the Si single crystal. However, in the measurement range, it was found that the absorption coefficient of the alumina molded body is as low as that of the Si single crystal, and can be sufficiently used as a high refractive index transmission material for terahertz waves. Also, from the evaluation results of the spectral shapes of the refractive index and the absorption coefficient, it was found that even 2.5 THz or more can be sufficiently used.

The method of manufacturing the alumina plate material is a powder forming process of filling the alumina powder into the mold cavity and compacting it using a mold having a desired shape, and sintering the alumina formed body after the powder forming process. And Sintering as the optical component. The plate-like alumina molded body manufactured by powder molding also has a high refractive index of about 3.1 and a low absorption coefficient in the terahertz region as in the injection molding, and is useful as a high refractive index transmission material for terahertz waves I found that.

By changing the mold shape, it is possible to mass-produce an alumina molded body having a desired shape that transmits the terahertz wave. That is, the said manufacturing method can form the optical component which is formed with an alumina and the electromagnetic wave of terahertz permeate | transmits the inside of the said alumina.

Second Embodiment
In this embodiment, the result of manufacturing an aspheric lens as an optical component that transmits the electromagnetic wave of terahertz wave will be described. FIG. 5 is a view showing the shape (design value) of an aspheric lens designed for alumina having a refractive index of 3.16. The lens shape is a flat surface on one side and an aspheric convex shape on the opposite surface. The horizontal axis (R axis) is the distance from the optical axis of the lens (R; unit is mm), and the vertical axis is the lens thickness from the lens plane to the optical axis direction (y; unit in mm). In the figure, numerical data of lens shapes are shown as a table. In this lens, by placing the terahertz wave point oscillation source at the position of (R, y) = (0, -0.2), the terahertz wave beam collimated to the alumina lens side can be extracted.

The injection molding method of Embodiment 1 was used to manufacture an aspheric lens of the design value of FIG. As a result of measuring the cross-sectional shape in 2 planes orthogonal including the optical axis of the manufactured aspherical lens using a three-dimensional measuring device, it confirmed that the aspherical lens as a design value was able to be manufactured. Note that "as designed" means the following. The manufacturing error of the aspheric lens was on the order of μm. Since the wavelength of the 1 THz terahertz wave is 300 μm, the manufacturing error is 1/10 or less of the wavelength. For this reason, the manufactured aspheric lens has sufficient accuracy as an optical component.

Moreover, as a result of measuring a refractive index and an absorption coefficient similarly to Embodiment 1 using this lens, it is understood that an absorption coefficient is as low as Si single crystal by refractive index 3.16 similarly to Embodiment 1. The In the injection molding, the alumina molded body molded by the mold was subjected only to the heat treatment of degreasing and baking, and the aspherical shape could be realized with high accuracy although the aspherical surface side was not polished. This indicates that the alumina material is a transparent material for terahertz wave excellent in mass productivity.

Third Embodiment
In this embodiment, a terahertz wave module including an optical component formed of alumina and an electromagnetic wave emitting unit for emitting a terahertz electromagnetic wave into the alumina of the optical component will be described.

The result of manufacturing a terahertz wave generation module in which a photomixer chip of UTC-PD (single traveling carrier-photodiode) structure is mounted on the back surface using the alumina aspheric lens shown in Embodiment 2 will be described. FIG. 6 is a view for explaining the structure of the terahertz wave generation module of this embodiment. In the terahertz wave generation module, the aspherical lens 1-2 'manufactured in the second embodiment is inserted into the mounting hole 1-1a' of the housing 1-1 '. The photo mixer chip 1-3 'is disposed at the center of the back surface (anti-lens side) of the aspheric lens 1-2'. The photomixer chip 1-3 'is a back illuminated type. Further, the upper reflecting mirror 1-5 ', the first lens 1-6', the lens holding part 1-7 ', and the second lens 1-8' are disposed at predetermined positions in the housing 1-1 '. The terahertz wave generation module transmits an optical signal incident from the optical fiber 1-9 'to the photo mixer chip 1- via the second lens 1-8', the first lens 1-6 ', and the upper reflecting mirror 1-5'. Irradiate the back of 3 '. The photo mixer chip 1-3 'converts the light signal into a terahertz electromagnetic wave and emits it to the aspheric lens 1-2' side. Therefore, the terahertz wave generation module outputs a terahertz electromagnetic wave according to the input light signal. The terahertz wave generation module may have a structure in which the first lens 1-6 ′ is directly incident on the back surface of the chip without the upper reflecting mirror 1-5 ′.

Next, the results of evaluating the characteristics of the terahertz wave generation module will be described next. For measurement, light of two wavelengths with different frequencies of 1.55 μm band is made incident to the terahertz wave generation module from the optical fiber 1-9 ', and the difference in the light frequency is changed from 300 GHz to 1800 GHz, and generated at that time. The terahertz wave beam transmitted through the aspheric lens 1-2 'was measured by a Golay cell (power meter for terahertz wave).

The two light waves of different frequencies incident on the optical fiber input section are condensed on the photo mixer chip 1-3 '. In the photo mixer chip 1-3 ', carriers (electrons and holes) are generated corresponding to each light wave. Although the photocurrent flows between the anode and the cathode by this carrier, since the frequency of the two light waves is different, a beat corresponding to the frequency difference is generated. The photocurrent is modulated corresponding to the beat, and as a result, an alternating electric field is generated between the anode and the cathode. An antenna integrated on the photo mixer chip 1-3 'is excited by this AC electric field, and a terahertz wave corresponding to a beat frequency (difference frequency between two light waves) is emitted. The terahertz wave is collected by the aspheric lens 1-2 'and taken out to the outside. The two types of light had almost the same light quantity, and the total light quantity was 28 mW. When 28 mW of light was incident, the photocurrent generated by the photo mixer chip 1-3 'was 6 mA.

FIG. 7 shows the results of measuring the terahertz wave output from the terahertz wave generation module of FIG. 6 while changing the difference frequency of the input light. A terahertz wave of 1 μW was observed as a terahertz wave of 1 THz. This value is a terahertz wave output substantially equivalent to the case where a Si spherical lens is used instead of the alumina aspheric lens 1-2 'in the terahertz wave generation module of FIG. For the Si spherical lens, the UTC-PD chip is attached under the condition that the spherical aberration becomes zero. In the case of the Si spherical lens, since the terahertz wave emitted from the module is a diffused beam, if the confocal system using two terahertz wave lenses between the module and the Golay cell is not configured, the terahertz wave efficiency of the golay cell Although the light can not be well incident, in the case of the alumina aspheric lens 1-2 ′ of this embodiment, the terahertz wave beam can be efficiently incident on the Golay cell without forming a confocal system between the module and the Golay cell. This is evidence that the terahertz wave beam is emitted in a collimated state by the aspheric lens 1-2 '.

Fourth Embodiment
The terahertz wave generation module of the present embodiment has the same structure as the terahertz wave generation module of FIG. 6, but the photomixer chip 1-3 'is a photoconductive antenna using LT (low temperature growth) InGaAs instead of UTC-PD. It is a chip. As in the case of UTC-PD, the antenna surface of the photoconductive antenna was mounted at a position 0.2 mm away from the planar portion of the alumina aspheric lens.

Characteristic evaluation of the terahertz wave generation module of the present embodiment was performed as follows. Pulsed light of 1.55 μm band was made incident from the optical fiber 1-9 '. In practice, a femtosecond pulsed fiber laser of 1.65 μm band was used.
Assuming that the time width of the light pulse is Δt (sec) and the spectrum width of this pulse light is Δf (sec ⁻¹ ),
ΔtΔf = k
(K is a constant determined by the pulse waveform shape, k = 0.441 for Gaussian pulse)
Is established. That is, incidence of pulsed light is equivalent to simultaneous incidence of light of many frequencies in the range of Δf. Therefore, a terahertz wave in the range of Δf is generated from the photoconductive antenna chip on which the pulse light is incident. For example, when a Gaussian light pulse (Δt = 0.1 psec) is incident, the light pulse is incident with light having a frequency component up to Δf = 4.4 THz, so from the photoconductive antenna chip Generates terahertz waves of up to 4.4 THz.
Further, as described in the third embodiment, it was found that the terahertz wave generated in this module is collimated by the aspheric lens 1-2 ′ and output to the outside.

Fifth Embodiment
In this embodiment, a terahertz wave module including an optical component formed of alumina and an electromagnetic wave receiving unit that receives a terahertz electromagnetic wave from the alumina of the optical component will be described.

The terahertz wave reception module of this embodiment has the same structure as the terahertz wave generation module of FIG. 6, but a reception chip is disposed as an alternative to the photo mixer chip 1-3 '. The receiving chip is, for example, one in which a bow-tie antenna is integrated on a Schottky barrier diode (SBD).

The terahertz wave generation module described in the third embodiment is used as the terahertz wave transmitter. Two light waves of a terahertz wave with a difference frequency of 1 THz were input to the terahertz wave transmitter at 28 mW. The terahertz wave transmitter and the terahertz wave receiving module of the present embodiment are opposed by 10 cm and face each other.

For comparison, the same experiment was conducted with a terahertz wave receiving module using only a lens portion of a Si spherical lens. In the terahertz wave receiving module for comparison using the Si spherical lens, the detection current could not be detected in the SBD. On the other hand, in the terahertz wave receiving module of this embodiment, the detection current can be detected in the SBD, and the collimated output of the alumina aspheric lens can be demonstrated, and the alumina aspheric lens has excellent performance as an optical material for terahertz wave transmission. It turned out that it was.

(Effect of this embodiment)
As described above, according to the present invention, it is possible to realize various optical components made of alumina that can be injection-molded or powder-molded. By using molding technology instead of cutting, mass production and price reduction can be expected. By using alumina having a high refractive index and low loss in the terahertz region, a module having a simple structure in which a semiconductor chip for terahertz wave generation or reception is directly mounted on an alumina lens can be realized. Further, in the above embodiment, the transmitting / receiving module combined with a photo mixer, a Schottky barrier diode, etc. is shown, but the semiconductor device having the transmitting / receiving function is not limited to these, and a resonant tunnel diode or the like is used. Also included are pure electronic devices.

(Other embodiments)
Although the aspheric lens has been described in the above embodiment, spherical lenses, cylindrical lenses, corner cubes, prisms, beam splitters, mirrors, polarizers, windows, microlens arrays, etc. can also be molded with alumina by the above-described manufacturing method. And an optical component with high refractive index and low loss in the terahertz region.

[Cylindrical lens]
A lens having a shape as shown in FIG. 8 was manufactured as a cylindrical lens. The manufacturing method is the injection molding described in the first embodiment. The designed values and measured values of the parameters of the cylindrical lens are as follows.
Design value A = B = 10 mm Actual value A = 9.98 mm B = 10.01 mm
Design value fb = 6.0 mm Actual value fb = 5.98 mm

[Prism, corner cube]
An optical component having a shape as shown in FIG. 9 was manufactured as a prism. The manufacturing method is the injection molding described in the first embodiment. The designed values and measured values of the parameters of the prism are as follows.
Design value A = B = C = 10 mm
Measured value A = 9.98 mm B = 10.01 mm C = 10.02 mm
A terahertz wave was made incident by this prism as shown in FIG. The light was incident perpendicularly to the A plane. The critical angle of alumina was about 18 degrees, and it was confirmed that the light was totally reflected from the C surface and emitted from the B surface as expected, and it was found that it functions as a prism. Although a corner cube was also manufactured, a desired function could be realized in the same manner as the above-mentioned prism.

[Beam splitter, mirror, window]
A wedge-shaped optical component as shown in FIG. 11 was manufactured as a beam splitter. The manufacturing method is the powder molding described in the first embodiment. Design values and measured values of beam splitter parameters are as follows.
Design value D = 20 mm Actual value D = 19.98 mm
Design value t = 2 mm Actual value t = 1.98 mm
Design value W = 2 degrees Actual value W = 1.9 degrees Design characteristics by terahertz wave with an incident angle of 45 degrees are the expected reflectance of 9.6% for the refractive index of alumina at p-polarization incidence . The measured value with this beam splitter is 8.5%, and it was found that the expected function was realized. In addition, the function as a mirror was also confirmed by vapor-depositing metal on this beam splitter. In addition, the window is used with the terahertz wave vertically incident using the above-mentioned beam splitter, and the expected characteristics are also obtained. It goes without saying that as a mirror, not only a flat surface but also an off-axis parabolic mirror can be handled by the shape polarization of the mold.

[Aspheric micro lens array]
Optical components of the following parameters were manufactured as an aspheric microlens array. The manufacturing method is the injection molding described in the first embodiment.
Design value: Lens arrangement (3 × 3), distance between each lens is 125 μm, and mass arrangement lens shape: shape of lens shape described in FIG. 5 reduced to 1/40 The microlens array actually created is Although the deviation from the design position of the aspheric surface part was about 5μ, it is 1/10 or less compared to the wavelength of the terahertz wave, and it has been confirmed that the function as a lens has no problem.

1-1, 1-1 ': Case 1-1a, 1-1a': Mounting hole 1-2: spherical lens (silicon)
1-2 ': Aspheric lens (alumina)
1-3, 1-3 ': photo mixer chip 1-4: lower reflecting mirror 1-5, 1-5': upper reflecting mirror 1-6, 1-6 ': first lens 1-7, 1-7 ': Lens holding part 1-8, 1-8': second lens 1-9, 1-9 ': optical fiber 2-1: spherical lens center 2-2: spherical lens surface 3-1: upper mold 3 -2: Lower mold 3-3: Raw material feeding passage 3-4: Raw material discharging passage 3-5: Alumina molded body

Claims

An optical component formed of alumina through which a terahertz electromagnetic wave passes.
The optical component according to claim 1, wherein at least a part of the surface has an aspheric lens shape.
The optical component according to claim 1, wherein the optical component is a cylindrical lens, a prism, a corner cube, a beam splitter, a mirror, a window, or a microlens array.
An optical component according to claim 1 or 2;
Electromagnetic wave emitting means for emitting a terahertz electromagnetic wave into the alumina of the optical component;
Module for terahertz wave provided with
An optical component according to claim 1 or 2;
Electromagnetic wave receiving means for receiving a terahertz electromagnetic wave from within the alumina of the optical component;
Module for terahertz wave provided with
An optical component manufacturing method for manufacturing the optical component according to any one of claims 1 to 3,
An injection molding step of filling and molding alumina in the mold cavity using a mold of a desired shape;
A sintering step of sintering the alumina molded body after the injection molding step into the optical component;
A method of manufacturing an optical component, comprising:
An optical component manufacturing method for manufacturing the optical component according to any one of claims 1 to 3,
A powder molding step of filling and compacting alumina powder in the mold cavity using a mold of a desired shape;
A sintering step of sintering the alumina molded body after the powder molding step into the optical component;
A method of manufacturing an optical component, comprising: