Optical sensor, optical detection device and terahertz / infrared Fourier spectrometer

Abstract

An optical sensor includes: a vibration driving section that generates vibration in accordance with an input signal; a resonance unit which is formed of an MEMS structure using a silicon material, and which has a double support beam that vibrates on the basis of the vibration transmitted by the vibration driving unit, and the resonance frequency of which changes in accordance with the input of light; and a vibration detection unit that detects vibration of the double support beam.

Description

Technical Field

[0001] The present invention relates to an optical sensor, a light detection device, and a terahertz / infrared Fourier spectrometer for detecting wide-spectrum light. This application claims priority based on Japanese Patent Application No. 2022-087832 filed in Japan on May 30, 2022, and the contents thereof are incorporated herein. Background Art

[0002] Optical sensors can be seen everywhere in our daily life, such as various remote controls, and have become an indispensable part of our lives. There are two types of optical sensors: photoelectric effect type and thermal effect type, among which pyroelectric detectors and bolometers are widely used. The above-mentioned bolometer is provided with a light absorbing part for receiving light and a detection part for detecting the temperature change in the light absorbing part. The light energy received by the light absorbing part is converted into heat energy, causing the temperature to rise, and the detection part detects the resistance value of the thermistor that changes accordingly.

[0003] However, conventional bolometers require cooling of the element or long-term heat integration to achieve high sensitivity. Therefore, it is difficult for conventional bolometers to achieve the performance of "room temperature operation", "high speed" and "high sensitivity" at the same time. In order to achieve the "room temperature operation", "high sensitivity" and "high speed" performance of bolometers, it is necessary to use physical quantities other than the usual resistance value as signals.

[0004] In recent years, research has been conducted on components called MEMS (Micro Electro Mechanical Systems), which are formed using semiconductor microfabrication technology and have a microstructure that enables mechanical operation. For example, Patent Document 1 and Non-Patent Document 1 describe a high-sensitivity bolometer-type optical sensor using a MEMS configuration.

[0005] The optical sensor described in Patent Document 1 and Non-Patent Document 1 has a double support beam formed of MEMS made of GaAs (gallium arsenide) using semiconductor micromachining technology, a vibration driving section that inputs vibration to the double support beam, and a vibration detecting section that detects the vibration of the double support beam. According to the optical sensor, the change in resonant frequency caused by thermal expansion due to temperature change of the beam can be detected with high sensitivity, thereby achieving the performance of "room temperature operation", "high sensitivity" and "high speed".

[0006] In addition, non-patent document 2 describes an optical sensor composed of a MEMS that detects infrared rays. The optical sensor described in non-patent document 2 has a MEMS structure composed of a paddle fixed by a thin wire, and is configured to detect a torsional resonance mode of the MEMS structure based on a change in resonance frequency caused by a thermal effect of light irradiated from the outside.

[0007] In addition, non-patent document 3 describes an optical sensor for detecting terahertz rays composed of SOI (Silicon on Insulator) MEMS. The optical sensor of non-patent document 3 adopts an SOI cantilever structure, is configured to drive the vibration of the cantilever structure caused by the thermal effect of light irradiated from the outside, and detects the vibration amplitude of the cantilever. Prior art literature Patent Literature

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2018-146294. Non-patent literature

[0009] [Non-patent document 1] Y. Zhang, S. Hosono, N. Nagai, SHSong, K. Hirakawa, "Fast and sensitive bolometric terahertz detection at room temperature through thermomechanical transduction", Journal of Applied Chemistry 125, 151602 (2019); https: / / doi.org / 10.1063 / 1.5045256. [Non-patent document 2] XC Zhang, EB Myers, JS Sader, and ML Roukes, “Nanomechanical Torsional Resonators for Frequency-Shift Infrared Thermal Sensing”, Nano Lett. 13, 1528 (2013); https: / / pubs.acs.org / doi / pdf / 10.1021 / nl304687p. [Non-patent document 3] Froberger, K., et al. “SOI-based micro-mechanical terahertz detector operating at room-temperature.” arXiv preprint arXiv:2204.03970 (2022). https: / / arxiv.org / pdf / 2204.03970.pdf. Summary of the invention Problems to be solved by the present invention

[0010] When an optical sensor is applied to a spectroscopic system or the like, there should be no insensitive band in sensitivity to the frequency of incident light. The bolometer-type optical sensor described in Patent Document 1 and Non-Patent Document 1 is composed of a MEMS having a GaAs substrate with polarity. According to this optical sensor, when input light in the terahertz band or infrared region passes through the GaAs substrate, there is a problem that an insensitive band is generated in which the detection sensitivity in the terahertz to infrared region is reduced due to interaction with phonons in the GaAs crystal (see Fig.14 ).

[0011] In addition, the response speed of the bolometer is determined by the thermal time constant. If the thermal conductivity is small, the thermal time constant becomes large, and the response speed of the sensor decreases. Generally speaking, when the size of the bolometer becomes small, the thermal time constant of the element becomes small, and high speed can be achieved. However, the problem with GaAs material is that due to its low thermal conductivity, when it is formed with a large light absorption area, the size of the element increases and the response speed deteriorates.

[0012] However, GaAs MEMS-based bolometers require the growth of multilayer GaAs / AlGaAs heterostructure substrates (see Fig.15 ). The growth technology of GaAs / AlGaAs heterostructures is complex, difficult to control and expensive, making large-scale manufacturing and application of MEMS bolometers difficult.

[0013] The present invention has been made in view of the above problems, and an object thereof is to provide an optical sensor, a light detection device, and a terahertz / infrared Fourier spectrometer capable of detecting light of a wide wavelength band including visible light, infrared light, and terahertz waves with high sensitivity. Means of solving the problem

[0014] One aspect of the present invention provides an optical sensor, comprising: a vibration driving unit, which generates vibration according to an input signal; a resonating unit, which is formed by a MEMS structure using a silicon material and has a double support beam, wherein the double support beam vibrates based on the vibration transmitted by the vibration driving unit, and the resonant frequency changes with the input of light; and a vibration detecting unit, which detects the vibration of the double support beam.

[0015] According to the present invention, light of a wide wavelength band including visible light, infrared light, and terahertz waves can be detected with high sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a diagram showing the structure of a wide spectrum light detection device according to an embodiment of the present invention. Figure 2 is a perspective view showing the structure of an optical sensor. Figure 3is a graph showing the transmission spectra of high-resistivity SOI and GaAs. Figure 4 It is a diagram showing the measurement results of the resonance spectrum of the optical sensor. Figure 5 This is a diagram showing changes in the oscillation spectrum when heat is input to the optical sensor. Figure 6 is a graph showing the resonant frequency shift of an optical sensor as a function of input thermal power. Figure 7 This is a diagram showing changes in the resonance frequency when visible light of 530 nm is input to the optical sensor. Figure 8 is a graph showing changes in the resonance frequency when 1.5 μm infrared light is input to the optical sensor. Fig. 9 is a graph showing changes in the resonance frequency when a terahertz wave of 0.3 THz is input to the optical sensor. Fig.10 is a graph showing changes in the resonance frequency when light of 0 to 5 THz is input to the optical sensor. Fig.11 is a graph showing changes in the resonance frequency when light of 0 to 20 THz is input to the optical sensor. Fig.12 : is a graph showing the measurement results of the frequency deviation when the modulation frequency is changed. Fig.13 It is a graph showing the performance of an optical sensor and conventional sensors. Fig.14 is a graph showing the performance of a conventional optical sensor having a MEMS structure formed of GaAs. Fig.15 FIG. 1 is a diagram showing the structure of a conventional substrate having a multilayer GaAs / AlGaAs heterostructure. Fig.16 : is a diagram showing the structure of a terahertz / infrared Fourier spectrometer to which an optical sensor is applied. DETAILED DESCRIPTION

[0017] like Figure 1 and Figure 2As shown, the wide-spectrum light detection device 1 includes: an optical sensor 10, which vibrates based on the input light L input from the light source R; a vibration detection device 20, which detects the vibration of the optical sensor 10; and a phase synchronization unit 30, which detects and adjusts the vibration frequency of the optical sensor 10 based on the detection value of the vibration detection device 20. The light source R can be any light source. For example, the input light L from the light source R includes but is not limited to natural light, solid-state light such as laser and LED light, transmitted light passing through a sample, reflected light from an object, and light emitted from a sample. The wavelength of the input light L is also not particularly limited, as long as it is included in the wavelength range that the optical sensor 10 can detect, such as visible light, infrared light, and terahertz waves. The light source R does not have to be a component of the wide-spectrum light detection device 1.

[0018] Exemplarily, the optical sensor 10 is formed of an optical element configured with a MEMS structure. In the following description, in the layer thickness direction (Z-axis direction in the figure) of the optical sensor 10, the +Z direction is referred to as the upper surface side, the -Z direction is referred to as the lower surface side, etc. The above directions are defined for convenience and do not necessarily indicate the use direction of the optical sensor 10.

[0019] The optical sensor 10 includes a substrate portion 13 formed in a plate-like shape, a resonance portion 11 formed on the substrate portion 13, and a sacrificial layer 12 for isolating the portions 13 and 11. For example, the optical sensor 10 is composed of a high-resistivity SOI (Silicon on Insulator) wafer made of silicon material (Si) used for semiconductor devices.

[0020] The sacrificial layer 12 is formed of a silicon oxide film (SiO2). The sacrificial layer 12 is formed of a pair of first legs 12A and a second leg 12B to support the resonating portion 11. The pair of first legs 12A and the second leg 12B have a rectangular cross-section in a plan view. A plate-shaped resonating portion 11 is provided on the upper surface 12C side of the sacrificial layer 12. The resonating portion 11 is made of a silicon (Si) material. The resonating portion 11 has a double support beam 11A formed in a flat plate shape and extending across a pair of sacrificial layers 12. A first support portion 11B supported by the first leg 12A is provided at one end of the double support beam 11A. A second support portion 11C supported by the second leg 12B is connected to the other end of the double support beam 11A. The double support beam 11A vibrates based on the vibration transmitted by the vibration drive portion 16 to be described later.

[0021] Exemplarily, the high-resistance SOI used in the optical sensor 10 is p-type, has a crystal plane orientation of (100), has a resistivity exceeding 1000 ohm*cm, and has a stable transmission spectrum in a wide band (see Figure 3). Therefore, the optical sensor 10 formed of SOI is capable of stable and highly sensitive optical measurement in a wide band. The optical sensor 10 made of SOI has a higher thermal conductivity than a conventional optical sensor made of GaAs, and can realize a high-speed bolometer.

[0022] As long as the double support beam 11A can absorb the wavelength band of the measured light, it can be used directly. In addition, in order to achieve a constant absorption rate in a wide wavelength range, it is best to provide a light absorption part 15 formed in the form of a rectangular film. The light absorption part 15 can be selected to use a metal film, an absorption film that uses a super surface plasmon structure to achieve high absorption rate, or a doped film that introduces impurities on the surface of the double support beam 11A and matches the sheet resistance with the vacuum electromagnetic wave resistance. In addition, when the above-mentioned light absorption part 15 is formed by a metal film, the metal film can be formed by depositing nickel or nickel-chromium (NiCr) alloy. The temperature of the light absorption part 15 rises when light is incident, and the temperature is transferred to the double support beam 11A. The impedance of the light absorption part 15 matches the impedance of the input light and the electromagnetic wave, converts the incident light into heat, and transfers the heat to the double support beam 11A. The light absorption part 15 transfers the temperature to the double support beam 11A, causing the double support beam 11A to expand and change its resonant frequency. The light absorbing portion 15 may be provided at any position as long as it can expand the double support beam 11A and change the resonance frequency, and is preferably provided at the center of the double support beam 11A. A vibration driving portion 16 for inputting vibration to the double support beam 11A is formed on the upper surface side of the first support portion 11B. A vibration detecting portion 17 for detecting vibration of the double support beam 11A is formed on the upper surface side of the second support portion 11C.

[0023] Exemplarily, the vibration driving unit 16 is composed of a pair of electrodes 16A and 16B. The pair of electrodes 16A and 16B are stacked on the upper surface side of the double support beam 11A along the layer thickness direction and are arranged at one end of the length direction of the double support beam 11A, that is, at Figure 2 The first support portion 11B side of the vibration drive section 16 is formed on the first support portion 11B side of the vibration drive section 16. An insulating layer 16C made of a piezoelectric material is formed between a pair of electrodes 16A and 16B. The vibration drive section 16 is composed of a piezoelectric element, which generates an electrostatic force between a pair of electrodes 16A and 16B based on an input voltage, thereby generating a potential difference between the pair of electrodes 16A and 16B, causing the insulating layer 16C to deform. The vibration drive section 16 generates vibration based on an input signal output from a vibration generating section 36 described later. The vibration drive section 16 vibrates by inputting an input signal of a voltage of a predetermined frequency generated by the vibration generating section 36 to a pair of electrodes 16A and 16B. The vibration drive section 16 can transmit the generated vibration to the double support beam 11A and vibrate the double support beam 11A.

[0024] The vibration driving unit 16 has an electrostatic element that applies a potential difference between the double support beam 11A and the substrate 13 and inputs vibration to the double support beam 11A based on the electrostatic effect, in addition to the piezoelectric element. In addition, the vibration driving unit 16 can also be an electromagnetic actuator that provides an electrode on the double support beam 11A and inputs vibration to the double support beam 11A by using the Lorentz force generated when a current flows through the electrode in the magnetic field generated around the double support beam 11A. The electromagnetic actuator can be configured so that an alternating current flows through the electrode in a direct current magnetic field, or it can be configured so that a direct current flows through the electrode in an alternating current magnetic field.

[0025] Exemplarily, the vibration detection unit 17 is composed of a pair of electrodes 17A and 17B. The vibration detection unit 17 has the same structure as the vibration driving unit 16. The pair of electrodes 17A and 17B are stacked in the layer thickness direction on the upper surface side of the double support beam 11A and are arranged at the other end of the length direction of the double support beam 11A, that is, Figure 2 The insulating layer 17C made of a piezoelectric material is formed between the pair of electrodes 17A and 17B. The vibration detecting portion 17 is composed of a pair of electrodes 17A, 17B. The vibration detecting portion 17 is composed of a piezoelectric element such that when the insulating layer 17C is deformed, a potential difference is generated between the pair of electrodes 17A and 17B. In the vibration detecting portion 17, the insulating layer 17C is deformed based on the vibration of a predetermined frequency generated in the double supporting beam 11A, and an output signal based on a voltage of a predetermined frequency is output according to the deformation of the insulating layer 17C.

[0026] The vibration detection portion 17 may be formed of a piezoresistive element that detects a resistance that changes according to stress generated by the vibration of the double support beam 11A, in addition to the piezoelectric element. The vibration detection portion 17 may include a laser Doppler vibrometer that receives reflected light of a laser beam irradiated to the double support beam 11A and detects the vibration of the double support beam 11A based on the Doppler effect.

[0027] The vibration detection device 20 amplifies the signal output from the vibration detection unit 17 and outputs an electrical signal to the phase synchronization unit 30. The phase synchronization unit 30 is composed of a general phase synchronization circuit. For example, the phase synchronization unit 30 includes: a phase comparator 32 for inputting the output value of the detection signal output from the vibration detection device 20; a low-pass filter 34 connected downstream of the phase comparator 32; and a vibration generating unit 36 ​​connected downstream of the low-pass filter 34 and connected to the phase comparator 32 and the vibration driving unit 16.

[0028] The phase comparator 32 compares the phases of the detection signal output from the vibration detection device 20 and the reference signal, and outputs a signal indicating the phase difference. The low-pass filter 34 inputs the signal output from the phase comparator 32, and outputs an output signal after the high frequency of the signal is cut off. The vibration generating unit 36 ​​outputs a signal whose frequency change direction is consistent with the direction in which the signal of the low-pass filter 34 is offset. The signal output from the vibration generating unit 36 ​​is input to the vibration driving unit 16 of the optical sensor 10 as an input signal, and is input to the phase comparator 32 as a reference signal. The signal output from the vibration generating unit 36 ​​is input to the vibration driving unit 16 as an input signal having the resonant frequency of the double support beam 11A of the optical sensor 10. The vibration driving unit 16 generates vibration based on the input signal and vibrates the double support beam 11A.

[0029] Next, the operation of the wide spectrum light detection device 1 is described. When no light is input to the optical sensor 10, the double support beam 11A vibrates at a natural resonant frequency. The initial value of the angular frequency corresponding to the resonant frequency f0 is expressed by the following formula (1): ω0=f0 / 2π.

[0030] [Formula 1]

[0031] Among them, the Young's modulus of the double-supported beam 11A is: E, the density is: ρ, and the constant according to the mode is: μ n , the span length of the double support beam 11A: L, and the thickness of the double support beam 11A: t. When light from the light source R irradiates the optical sensor 10, the light irradiated on the double support beam 11A is converted into heat at the light absorbing portion 15. The heat generated in the light absorbing portion 15 is transferred to the double support beam 11A. When the temperature of the double support beam 11A rises, the double support beam 11A undergoes thermal expansion. One end of the double support beam 11A is restricted by the first support portion 11B, and the other end is restricted by the second support portion 11C. Therefore, the double support beam 11A is compressed in the length direction due to thermal expansion, and a stress σ is generated inside. Under the action of the stress σ, the angular frequency ω0(σ)=f0 / 2π corresponding to the resonant frequency f0 of the double support beam 11A is expressed by the following formula (2).

[0032] [Formula 2]

[0033] As shown in formula (2), the angular frequency ω0 (σ) corresponding to the resonant frequency f0 changes linearly with the increase of thermal stress σ (<0). At this time, if the resonant frequency of the dual support beam 11A is detected based on the optical sensor 10, the power of the input light can be calculated. When the resonant frequency of the dual support beam 11A of the input light changes, the phase synchronization unit 30 is adjusted so that the signal of the changed resonant frequency is output from the vibration generating unit 36. By observing the signal output from the vibration generating unit 36, the resonant frequency of the dual support beam 11A can be obtained. Therefore, through the wide-spectrum light detection device 1, the input of light can be detected based on the offset of the resonant frequency of the dual support beam 11A due to the light input to the optical sensor 10.

[0034] In order to detect a small change in the resonance frequency f0 by the optical sensor 10, the quality factor (Q value) representing the vibration state of the mechanical resonance in the double support beam 11A should be as high as possible. B is the Boltzmann constant, T is the temperature, f0 is the resonant frequency, k is the spring constant of the double support beam 11A, Q is the Q value, and A is the amplitude. Then the relationship between the frequency noise density n f The sum of Q values ​​is expressed by the following formula (3).

[0035] [Formula 3]

[0036] Figure 4 The measurement result of the resonance spectrum of the optical sensor 10 measured based on the wide spectrum light detection device 1 is shown. According to the measurement result, the Q value of the optical sensor 10 is about 17000. According to the optical sensor 10, this value is more than twice that of a conventional MEMS optical sensor formed of GaAs. Therefore, compared with a conventional MEMS optical sensor made of GaAs, the optical sensor 10 can achieve lower noise and more accurate light measurement.

[0037] Figure 5 It shows a change in the oscillation spectrum when heat is input to the optical sensor 10. As shown in the figure, the optical sensor 10 generates thermal stress based on the input of light and softens, and the resonance frequency decreases accordingly. Figure 6 The functional relationship between the resonant frequency shift of the optical sensor 10 and the input thermal power is shown. In the figure, (A) shows the measurement result using a double support beam 11A with a size of 100 μm×30 μm×2.5 μm. Figure 5 As shown, the frequency shift increases linearly with the increase of thermal power, and the normalized thermal responsiveness of the sample is expressed by the following formula (4).

[0038] [Formula 4]

[0039] This thermal responsiveness can be increased by making the thickness of the double support beam 11A thinner or longer, for example. Figure 6 In the figure, (B) shows the measurement result when the double support beam 11A with a thickness of 0.8 μm is used. As shown in the figure, (B) has a frequency shift compared to (A), and the thermal responsiveness R increases to about 26.5W. -1 This measurement is close to the thermal response of optical sensors made of GaAs.

[0040] Figure 7 The change in the resonance frequency when 530 nm visible light is input to the optical sensor 10 is shown. Figure 8 A change in the resonance frequency when 1.5 μm infrared light is input to the optical sensor 10 is shown. Fig. 9 A change in the resonance frequency when a terahertz wave of 0.3 THz is input to the optical sensor 10 through the terahertz wave multiplier is shown. Fig.10 The diagram shows the change in resonance frequency when light from a thermal light source (bulb) is input to the optical sensor 10 via a far-infrared pass filter (cutoff frequency 5 THz) (ie, the input light has a frequency of 0 to 5 THz). Fig.11 The figure shows the change of the resonant frequency when the light from the heat light source (bulb) is input to the optical sensor 10 (i.e., the input light has a frequency of 0 to 20 THz) via a far infrared pass filter (cut-off frequency 20 THz). As shown in the figure, the optical sensor 10 is able to detect the resonant frequency changed due to the input of light. It can be seen that the optical sensor 10 is sensitive to light in the visible light and infrared light bands.

[0041] The optical sensor 10 can detect light of a specific wavelength band at high speed. The photothermal response speed of the optical sensor 10 is determined based on its thermal time constant. When the specific heat of silicon is c and the thermal conductivity is κ, the thermal time constant of the optical sensor 10 is expressed by the following formula (5).

[0042] [Formula 5]

[0043] Since the response speed of the optical sensor 10 is 1 / τ, the smaller τ is, the faster the response speed of the optical sensor 10 is. In order to prove the high response speed of the optical sensor 10, the modulation frequency of the input light is modulated and the shift of the resonance frequency is measured.

[0044] Fig.12The measurement results of the frequency shift Δf when the modulation frequency is changed are shown. As shown in the figure, when the optical sensor 10 is compared with a conventional optical sensor formed of GaAs of the same size, the thermal time constant of the optical sensor 10 is about 35 μs, while the thermal time constant of the conventional GaAs optical sensor 10 is about 100 μs. As shown in the measurement results, when the optical sensor 10 of the same shape is compared with the conventional optical sensor formed of GaAs, it can be seen that the thermal response of the optical sensor 10 is about three times faster than the thermal response of the conventional optical sensor formed of GaAs.

[0045] like Fig.13 As shown, the detection speed (Hz) of the optical sensor 10 is 100 to 1000 times faster than the thermal sensor of resistance or capacitance change used in the past, and has the same sensitivity. According to the wide-spectrum light detection device 1, the optical sensor 10 has a MEMS structure formed of a high-resistivity SOI material, and a bolometer with high transmittance can be realized at low cost. According to the wide-spectrum light detection device 1, a high-performance bolometer based on the optical sensor 10 operating at room temperature, with a wide band, high sensitivity, high speed and low cost can be realized.

[0046] According to the optical sensor 10, since it is formed of an SOI substrate, it can have high transmittance in a wide wavelength range and can measure from visible light, infrared rays to terahertz waves, realizing a high-speed, high-sensitivity sensor operating at room temperature. According to the optical sensor 10, since a cheaper SOI substrate structure than a GaAs heterostructure with a complicated growth process is used, MEMS bolometers can be mass-produced at low cost. Since the optical sensor 10 uses a general silicon semiconductor technology, it can be easily mass-produced.

[0047] The optical sensor 10 has a detection speed about three times faster than a conventional MEMS optical sensor formed of GaAs of the same shape because it is highly sensitive to light in a wide wavelength range from visible light to infrared and terahertz waves. The optical sensor 10 is made of silicon-based materials, so the growth process can be simplified and it can be made at a low cost. The wide-spectrum light detection device 1 using the optical sensor 10 does not have an insensitive band with reduced detection sensitivity from the terahertz to infrared region, and a wide-band, high-speed, high-sensitivity light detection device, spectroscopic device, and bio-imaging device can be realized.

[0048] When a dual-support beam resonator type optical sensor is formed using silicon-based materials, there is a problem of large internal stress in the beam structure deposited using a physical film forming method. However, the inventors have found that the above-mentioned internal stress problem can be solved by adopting a MEMS structure made of a crystalline SOI material (e.g., a single crystal SOI substrate) with low internal stress. When a MEMS dual-support beam structure made of the above-mentioned SOI material is adopted, the performance of the optical sensor can be further improved. For example, the example described in the above-mentioned non-patent document 2 uses physically deposited a-Si, so the internal stress of the MEMS structure is large. Therefore, only a torsional mode with insufficient thermal sensitivity can be used. Compared with the example described in non-patent document 2, the thermal sensitivity of the above-mentioned optical sensor 10 is about 20 times higher. Although non-patent document 3 describes an example using an SOI substrate, this does not take into account the internal stress of the beam structure as described above. Since the example described in non-patent document 3 adopts a cantilever structure, the initial stress inside the structure is insignificant. In addition, non-patent document 3 does not describe the crystallinity of the material. In addition, in the example recorded in non-patent document 3, due to the use of a cantilever structure, the thermal sensitivity is about 10nW / Hz 0.5 , compared with the above optical sensor 10, it is improved by more than 10 times.

[0049] The wide spectrum light detection device 1 using the optical sensor 10 can be applied to industrial fields that utilize near infrared, infrared, and terahertz bands. According to the wide spectrum light detection device 1 using the optical sensor 10, a terahertz infrared Fourier spectrometer (FTIR) can be realized, which is an essential device in fields such as materials, chemistry, pharmaceuticals, and biotechnology. The FTIR using the optical sensor 10 will be described below. In the following description, the same names and reference numerals will be used for the same components as in the above-mentioned embodiment, and repeated descriptions will be appropriately omitted.

[0050] like Fig.16 As shown, FTIR 100 includes a wide spectrum light detection device 1, which includes an optical sensor 10, a lens unit N, a light source R, an interference light generating unit U for generating interference light, and a computing device 40 for analyzing the light detected by the wide spectrum light detection device 1. FTIR 100 is a spectroscopic device configured to measure the interference waveform of light using an interferometer, and measure the intensity distribution of the spectrum of light by Fourier transforming the measured value. When using FTIR 100, a sample S is set in the wide spectrum light detection device 1, and FTIR 100 can check the optical characteristics of the sample S. In addition, in Fig.16In the embodiment, the sample S is arranged between the semi-transparent and semi-reflective mirror U1 of the interference light generating unit U and the lens unit N, but the arrangement of the sample S is not limited thereto and can be arranged at any position where spectroscopic measurement can be performed. The lens unit N is a lens shape made of silicon, and collects input light and inputs it to the optical sensor 10. The computing device 40 analyzes the spectrum of the light input to the optical sensor 10 and outputs it. For example, the computing device 40 is an information processing terminal device composed of a personal computer or the like.

[0051] Exemplarily, the interference light generating unit U is a Michelson interferometer, including a semi-transparent mirror U1, a first reflector U2 forming a fixed mirror, and a second reflector U3 forming a movable mirror. The semi-transparent mirror U1 receives the light L1 input from the light source R at an angle, and divides the light into two beams: a first light L2 which is a reflected light and a second light L3 which is a transmitted light. The first light L2 is reflected by the first reflector U2 and returns to the semi-transparent mirror U1. The second light L3 is reflected by the second reflector U3 and returns to the semi-transparent mirror U1.

[0052] The first light L2 and the second light L3 are combined in the semi-transparent mirror U1. The second reflector U3 is movable in the optical path direction, and the optical path length of the second light L3 has an optical path difference compared with the optical path length of the first light L2. Therefore, a phase difference occurs between the first light L2 and the second light L3 in the semi-transparent mirror U1, and interference light L4 is formed in the semi-transparent mirror U1. The interference light L4 generated in the semi-transparent mirror U1 is collected by the lens portion N formed by the silicon lens and input to the optical sensor 10. The interference light L4 input to the optical sensor 10 heats the double support beam 11A, and the vibration of the MEMS beam is excited by the vibration driving portion and detected by the vibration detection device 20. The resonant frequency of the double support beam 11A changes based on the interference light L4. The phase synchronization unit 30 detects the vibration frequency of the optical sensor 10. The detection value detected by the phase synchronization unit 30 is input to the computing device 40. The computing device 40 analyzes the spectrum of the light L1 based on the detection value detected by the phase synchronization unit 30. The calculation device 40 performs Fourier analysis on the interference waveform of the interference light L4 in the detection value, and performs spectrum analysis on the light L1 output from the light source R. The calculation device 40 outputs the spectrum of each wavelength component of the light L1.

[0053] The modulation frequency of the light generated by the movement of the second reflector U3 is proportional to the frequency of the light and the moving speed of the second reflector U3, so the scanning speed of the FTIR 100 depends on the detection speed of the optical sensor. The light intensity modulation frequency of the FTIR 100 is calculated by fm=2*f / c*v. Where f is the frequency of the light, c is the speed of light, and v is the speed of the moving mirror. For example, if the light is 10μm infrared light (frequency 30THz) and the speed of the moving mirror is 10mm / s, the modulation frequency of the light is 2kHz.

[0054] By applying the FTIR 100 of the optical sensor 10, the detection speed is about 100 to 1000 times faster than the pyroelectric detector used in the conventional FTIR, and the spectral distribution of light can be detected at high speed and high sensitivity. Through the FTIR100, a multi-channel spectrometer that can analyze the spectral distribution of light in the near-infrared, infrared and terahertz bands at high speed and high sensitivity can be realized. In addition, as long as the interference light generating unit U can generate interference light, it can also be replaced by an interferometer other than the Michelson interferometer. In addition, the optical sensor 10 in the FTIR100 can form an array, and by integrating the circuit of the vibration detection unit, an imaging element and thermal imaging technology that can detect near-infrared, infrared and terahertz waves at high speed can be realized, which can be applied to night driving assistance devices, etc.

[0055] The above-mentioned computing device 40 can be implemented by executing a program (software) through a hardware processor such as a CPU (Central Processing Unit). Some or all of these components can be hardware (circuit parts), such as LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array) and GPU (Graphics Processing Unit), etc., or can be implemented by the collaboration of software and hardware. The program can be pre-stored in a storage device such as a HDD (Hard Disk Drive) or flash memory provided in the computing device 40, or can be stored in a removable storage medium such as a DVD or CD-ROM. The storage medium can be installed by attaching it to a drive device.

[0056] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various changes and substitutions can be made without departing from the gist of the present invention. The configurations described in the above embodiments can be replaced with each other. Explanation of symbols

[0057] 10 Optical Sensor 11. Resonance section 11A Double support beam 15 Light absorption part 16. Vibration drive unit 17. Vibration detection unit 20. Vibration detection device 30 Phase synchronization unit 36. Vibration generating unit 40 Computing device L Input light L1 Light R Light Source

Claims

1. An optical sensor, characterized in that: include: A vibration driving unit generates vibration according to an input signal; a resonance part formed of a MEMS structure using a silicon material, having a double support beam, the double support beam vibrating based on the vibration transmitted by the vibration drive part, and the resonance frequency changing with the input of light; The vibration detection unit detects the vibration of the double support beam.

2. The optical sensor according to claim 1, characterized in that The MEMS structure is formed of SOI (Silicon on Insulator) material.

3. The optical sensor according to claim 1 or 2, characterized in that: The double supporting beam is disposed between the vibration driving part and the vibration detecting part, and a light absorbing part is formed thereon, and the light absorbing part transmits temperature through input of light.

4. The optical sensor according to claim 3, characterized in that The vibration driving unit is composed of a piezoelectric element provided at one end of the double support beam in the longitudinal direction.

5. The optical sensor according to claim 3, characterized in that The vibration driving part is formed by an electrostatic element provided at one end of the double support beam in the longitudinal direction.

6. The optical sensor according to claim 3, characterized in that The vibration detection unit is composed of a piezoelectric element provided at the other end in the longitudinal direction of the double support beam.

7. The optical sensor according to claim 3, characterized in that The vibration detection unit is formed by a piezoresistive element provided at the other end in the longitudinal direction of the double support beam.

8. The optical sensor according to claim 3, characterized in that The MEMS structure comprises: The substrate part is formed into a flat plate shape; a pair of sacrificial layers formed on the substrate portion; The resonance part is made of silicon material and has the double supporting beams formed in a plate shape to span the pair of sacrificial layers.

9. A light detection device, characterized in that: include: An optical sensor is formed of a vibration driving unit that generates vibration based on an input signal and a MEMS structure using a silicon material, and has a resonance unit including a double support beam, and a vibration detection unit that detects the vibration of the double support beam, wherein the double support beam vibrates based on the vibration transmitted by the vibration driving unit, and the resonance frequency changes with the input of light; a vibration detection device that amplifies and outputs the vibration of the optical sensor; The phase synchronization unit detects the vibration frequency of the optical sensor based on the output value of the vibration detection device.

10. The light detection device according to claim 9, characterized in that The MEMS structure is formed of SOI material.

11. A terahertz / infrared Fourier spectrometer, characterized in that: include: An optical sensor, formed of a vibration driving part that generates vibration based on an input signal and a MEMS structure using a silicon material, having a resonance part including a double support beam, a vibration detection part that detects the vibration of the double support beam, and a light absorption part that transmits temperature to the double support beam by input of light, wherein the double support beam vibrates based on the vibration transmitted by the vibration driving part, and the resonance frequency changes with the input of light; a light source for inputting input light to the optical sensor; a vibration detection device that amplifies and outputs the vibration of the optical sensor; a phase synchronization unit, which detects the vibration frequency of the optical sensor based on the output value of the vibration detection device; The computing device analyzes the spectrum of the light based on the detection value detected by the phase synchronization unit.

12. The terahertz / infrared Fourier spectrometer according to claim 11, characterized in that: The MEMS structure is formed of SOI material.

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