CN215910734U - Conversion device for far infrared light polarization state - Google Patents
Conversion device for far infrared light polarization state Download PDFInfo
- Publication number
- CN215910734U CN215910734U CN202023088248.8U CN202023088248U CN215910734U CN 215910734 U CN215910734 U CN 215910734U CN 202023088248 U CN202023088248 U CN 202023088248U CN 215910734 U CN215910734 U CN 215910734U
- Authority
- CN
- China
- Prior art keywords
- linear polarizer
- polarization state
- far
- linear
- light
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
- Polarising Elements (AREA)
Abstract
The utility model belongs to the technical field of far infrared laser, in particular to a far infrared light polarization state conversion device, which comprises: the device comprises a first linear polarizer, a beam splitting plate, a second linear polarizer, a plane mirror, a third linear polarizer, a lens and a detector. The far-infrared light polarization state conversion device provided by the utility model can realize the periodic regulation and conversion from linearly polarized light to near circularly polarized light to linearly polarized light, has the advantages of wide working wavelength range, good polarization state conversion effect and the like, and compared with a 45-degree incident linear polarizer mode, the far-infrared light polarization state conversion device breaks through the limitation of the distance between a plane reflector and the linear polarizer in the polarization state conversion and adjustment process by utilizing the characteristic of high beam overlapping degree of the normal incident light in the transmission process through the linear polarizer, improves the signal-to-noise ratio of the polarization characteristic of the combined laser, reduces the difficulty in conversion and adjustment, and realizes the conversion and adjustment of the far-infrared light polarization state in a wider wavelength range.
Description
Technical Field
The utility model belongs to the technical field of far infrared laser, and particularly relates to a far infrared light polarization state conversion device.
Background
Polarization characteristics are important parameters that describe the temporal and spatial variation of the far infrared optical electric field component, in addition to radiation frequency, power and beam quality. For example, in the field of communications, the polarization state of electromagnetic waves can be used as an independent dimension of modulation, and another modulation means besides frequency modulation and amplitude modulation is realized; in imaging application, the polarization state of electromagnetic radiation changes along with the appearance of the surface of a target object, and after a corresponding polarization detection means is added, the combined detection of the polarization state and the amplitude of the electromagnetic radiation in the imaging process can be realized, so-called holographic imaging is realized. Therefore, the utilization and detection of the polarization state play an important role in the application of electromagnetic radiation, the polarization conversion technology of far infrared light is developed, the application advantages of the electromagnetic wave frequency band can be improved, and different application effects can be obtained.
However, in the far infrared band, especially in the band above 30 microns, the means for generating electromagnetic radiation is relatively lacking, and most of the currently generated effective radiation is mainly in the linear polarization state, and is greatly limited in practical application. Therefore, it is very practical to develop a means for realizing polarization state conversion of far infrared light to meet the practical application requirement of the frequency band. The existing polarization conversion means mainly starts from the materials and microstructures of the converter, and realizes the change of the polarization state of emergent laser by designing the adjustment effect on the phase of incident laser. However, the radiation wavelength range of the above-mentioned polarization conversion method is small, and a polarization converter with a determined design structure and material can only realize the polarization conversion function within a certain wavelength range, and when the method is applied to multi-wavelength electromagnetic radiation, a plurality of polarization converters need to be configured, which increases the complexity of the system. In order to simplify the application system, an ultra-wide spectrum far infrared light polarization converter is proposed, in which incident polarized light and a linear polarizer form an incident angle of 45 degrees, and a good polarization conversion effect is obtained. However, due to the limitation of the incident angle of 45 degrees, the plane mirror for adjusting the polarization state must be very close to the off-line polarizer, usually within the distance between two wavelengths, to ensure that two beams of light forming interference can be well overlapped, when the plane mirror is more than two wavelengths away from the linear polarizer, due to the existence of the incident angle of 45 degrees, the overlapping area of the two beams of laser light after being overlapped becomes small, so that the polarization state of the combined laser light is not pure, the polarization conversion effect is poor, and this limitation has a great influence on the far infrared light with the wavelength less than 50 micrometers. Therefore, there is a need to develop a device and a method that can realize polarization conversion of wide-spectrum far-infrared light and can realize efficient conversion of polarization state of incident far-infrared light by adjusting a plane mirror in a large range.
SUMMERY OF THE UTILITY MODEL
In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a far-infrared polarization state conversion apparatus, and the apparatus and the implementation method thereof utilize the characteristic that interference light formed by normal incidence far-infrared light on the surface of a linear polarizer has high coincidence, improve the signal-to-noise ratio of the polarization characteristic of the combined laser, and in principle, realize effective adjustment and polarization conversion of wide-spectrum far-infrared polarized light, and provide a potential means for polarization imaging, ellipsometry and signal modulation of far-infrared frequency band.
To achieve the above and other related objects, the present invention provides a device for converting the polarization state of far infrared light, comprising: the device comprises a first linear polarizer, a beam splitting sheet, a second linear polarizer, a plane reflector, a third linear polarizer, a lens and a detector; the beam splitting sheet, the third line polaroid, the lens and the detector are positioned on the same straight line, and the first line polaroid, the second line polaroid and the plane reflector are positioned on the same straight line and are perpendicular to the beam splitting sheet.
The far infrared parallel light is converted into linearly polarized light after passing through the first linear polarizer and reaches the second linear polarizer after passing through the beam splitting sheet;
the second linear polarizer reflects a part of far infrared linearly polarized light, and the other part of the linearly polarized light reaches the plane reflector after penetrating through the second linear polarizer;
the plane reflector reflects the far infrared light which penetrates through the second linear polarizer, then penetrates through the second linear polarizer again, and interferes with the far infrared polarized light which is reflected on the second linear polarizer, and the combined interference light is reflected by the beam splitting sheet and reaches the detector after passing through the third linear polarizer and the lens;
the third linear polaroid is suitable for detecting the polarization characteristic of the interference light after beam closing;
the lens is used for converging the combined interference light, so that all the interference light is detected by the detector.
In a preferred embodiment of the utility model, the wavelength of the operating laser of the device covers 20 μm to 200 μm.
In a preferred embodiment of the present invention, the first, second, and third linear polarizers are all polymer substrates, and the surfaces of the substrates are diffraction gratings formed by metal wires.
As a preferred scheme of the utility model, the beam splitting sheet is a double-sided polished high-resistance silicon sheet.
In a preferred embodiment of the present invention, the flat mirror is a gold-plated surface of a glass substrate.
As a preferable scheme of the utility model, the lens is a double-sided coated high-resistance silicon lens.
In a preferred embodiment of the present invention, the detector is a thermal detector.
The utility model has the beneficial effects that: the utility model adopts the normal incidence linear polarizer to realize the polarization conversion of far infrared light, can realize the periodic adjustment and conversion from linearly polarized light to nearly circularly polarized light to linearly polarized light, utilizes the characteristic of high beam overlapping degree of the normal incidence light in the process of transmitting through the linear polarizer, improves the signal-to-noise ratio of the polarization characteristic of the combined beam laser, breaks through the limitation of the distance between a plane reflector and the linear polarizer in the polarization state conversion and adjustment process, has a wider working wavelength range than that under the condition of 45-degree incidence, realizes the effective adjustment and polarization conversion of the wider far infrared polarized light wavelength range in principle, and provides a potential polarization regulation and control means for the polarization imaging, the ellipsometry and the signal modulation of the far infrared frequency band.
Drawings
Fig. 1 is a schematic diagram of the structure and light path of the far infrared polarization conversion device of the present invention.
Fig. 2 shows the polarization state of the combined laser beam with phase change, which is caused by the optical path difference formed by the movement of the plane mirror.
Fig. 3 is a schematic flow chart of a method for implementing the far infrared light polarization state conversion device of the present invention.
In the figure, 1-incident far infrared parallel light, 2-a first linear polarizer, 3-a beam splitter, 4-a second linear polarizer, 5-a plane reflector, 6-a third linear polarizer, 7-a lens and 8-a detector.
Detailed Description
For the purpose of enhancing the understanding of the present invention, the present invention will be described in further detail with reference to the accompanying drawings and examples, which are provided for the purpose of illustration only and are not intended to limit the scope of the present invention.
Example (b): referring to fig. 1, a device for converting far-infrared light polarization state at least includes: a first linear polarizer 2, a beam splitter 3, a second linear polarizer 4, a plane mirror 5, a third linear polarizer 6, a lens 7 and a detector 8; the far infrared parallel light 1 is converted into far infrared linear polarized light with equal electric field components in the horizontal direction and the vertical direction after passing through the first linear polarizing film 2, and reaches the second linear polarizing film 4 after penetrating through the beam splitting sheet 3; the second linear polarizer 4 reflects a part of far infrared linearly polarized light, and the other part of linearly polarized light reaches the plane reflector 5 after penetrating through the second linear polarizer 4; the plane mirror 5 reflects the far infrared light transmitted through the second linear polarizer 4, then transmits the far infrared light through the second linear polarizer 4 again, and interferes with the far infrared polarized light combined beam reflected on the second linear polarizer 4, and the combined interference light is reflected by the beam splitting sheet 5, passes through the third linear polarizer 6 and the lens 7, and then reaches the detector 8; the third linear polarizer 6 is adapted to detect the polarization characteristic of the interference light after beam closing; the lens 7 is used for converging the combined interference light, so that all the interference light is detected by the detector 8, and the measurement of the polarization state of the combined beam polarized light is finally completed by rotating the linear polarization angle of the third linear polarizer 6 and simultaneously recording the signal amplitude on the detector 8.
The wavelength range of the far infrared parallel light is 20-200 μm by way of example, and preferably, in the present embodiment, the wavelength of the far infrared light is 72 μm, and the beam diameter is 10 mm.
The first linear polarizer, the second linear polarizer and the third linear polarizer are the same linear polarizer, a high density polyethylene material is used as a substrate, aluminum metal wires are evaporated on the surface of the substrate, the operating wavelength range of the linear polarizer covers 5-1000 μm, and preferably, the clear aperture of each linear polarizer is 50.8 mm in the embodiment.
By way of example, the beam splitting sheet is a double-sided polished high-resistance silicon wafer, and preferably, in this embodiment, the resistivity of the high-resistance silicon wafer is greater than 5000 Ω · cm, the diameter is 101.6 mm, and the thickness is 500 μm.
The flat reflector is a gold-plated surface of a glass substrate, and has a reflectivity of more than 98% for far infrared light, and preferably, in the embodiment, the diameter of the flat reflector is 76.2 mm.
By way of example, the lens is a double-sided coated high-resistance silicon lens, and preferably, in the embodiment, the focal length of the lens is 150 mm, the diameter of the lens is 50.8 mm, the coating material is a polymer, and the coating thickness is 18 μm.
By way of example, the thermal detector is a pyroelectric detector, and preferably, in the present embodiment, the noise equivalent power in the far infrared band is less than 300 pW/hz0.5.
In the device, far infrared parallel light 1 is incident to a polarization adjusting part consisting of a second linear polarizer 4 and a plane reflector 5 in a normal incidence mode, so that far infrared light reflected by the plane reflector 5 is completely overlapped with far infrared light reflected by the second linear polarizer 4, and compared with a 45-degree incidence mode, the device improves the overlapping rate and the beam combination interference effect of the two beams of light and improves the signal-to-noise ratio of the polarization characteristic of the combined laser.
Referring to fig. 3, the present invention further provides a method for implementing polarization conversion and adjustment of far-infrared light by using the device for converting the polarization state of far-infrared light according to the first embodiment, wherein the method comprises: the implementation method comprises the following steps:
1) the first linear polarizer 2 converts the incident far infrared parallel light 1 into far infrared linearly polarized light with equal electric field component in horizontal and vertical directions, and the converted linearly polarized light reaches the second linear polarizer 4 after passing through the beam splitting sheet 3;
2) a part of the linearly polarized laser light reaches the plane reflector 5 after passing through the second linearly polarized plate 4, and passes through the second linearly polarized plate 4 again after being reflected by the plane reflector 5, and converges with the linearly polarized light reflected by the surface of the second linearly polarized plate 4 to form interference light;
3) the converged interference light passes through the third linear polarizer 6 and the lens 7 and then reaches the detector 8, and the third linear polarizer 6 and the detector 8 detect the converged interference light to obtain the actual polarization state of the interference light;
4) and adjusting the distance between the plane reflector 5 and the second linear polarizer 4, wherein the adjustment step length is 1/24 (namely 3 mu m) of the wavelength of the incident far infrared parallel light 1, and the phase changed in each step is pi/6 according to the relation that the optical path difference is equal to 2 times of the distance between the plane reflector 5 and the second linear polarizer 4. FIG. 2 shows the measurement results of the polarization states of the combined laser beams with phase differences of 0, pi/2, pi, 3 pi/2 and 2 pi, which respectively correspond to linearly polarized light, near-circularly polarized light, linearly polarized light, near-circularly polarized light and linearly polarized light. The phase of the polarized light reflected by the plane mirror 5 and reaching the surface of the second linear polarizer 4 forms periodic variation, so that the polarized light interferes with the polarized light reflected by the surface of the second linear polarizer 4 to form combined laser in different polarization states, thereby realizing polarization conversion of incident polarized light, and the polarization state of the combined laser in each state can be measured through the third linear polarizer 6 and the detector 8.
The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the utility model as claimed. The scope of the utility model is defined by the appended claims and equivalents thereof.
Claims (5)
1. A far infrared light polarization state conversion device is characterized in that: the device comprises a first linear polarizer, a beam splitting plate, a second linear polarizer, a plane reflector, a third linear polarizer, a lens and a detector; the beam splitting sheet, the third linear polaroid, the lens and the detector are positioned on the same straight line, the first linear polaroid, the second linear polaroid and the plane reflector are positioned on the same straight line and are perpendicular to the beam splitting sheet, the first linear polaroid, the second linear polaroid and the third linear polaroid are all polymer substrates, diffraction gratings formed by metal wires are arranged on the surfaces of the substrates, and far infrared parallel light is converted into linearly polarized light after passing through the first linear polaroid and reaches the second linear polaroid after passing through the beam splitting sheet; the second linear polarizer reflects a part of far infrared linearly polarized light, and the other part of the linearly polarized light reaches the plane reflector after penetrating through the second linear polarizer; the plane reflector reflects the far infrared light which penetrates through the second linear polarizer, then penetrates through the second linear polarizer again, and interferes with the far infrared polarized light which is reflected on the second linear polarizer, and the combined interference light is reflected by the beam splitting sheet and reaches the detector after passing through the third linear polarizer and the lens; the third linear polaroid is suitable for detecting the polarization characteristic of the interference light after beam closing; the lens is used for converging the combined interference light, so that all the interference light is detected by the detector.
2. The far-infrared light polarization state conversion device according to claim 1, wherein: the beam splitting piece is a double-sided polished high-resistance silicon chip.
3. The far-infrared light polarization state conversion device according to claim 1, wherein: the plane mirror is a gold-plated surface of a glass substrate.
4. The far-infrared light polarization state conversion device according to claim 1, wherein: the lens is a high-resistance silicon lens with a double-sided coated film.
5. The far-infrared light polarization state conversion device according to claim 1, wherein: the detector is a thermal detector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202023088248.8U CN215910734U (en) | 2020-12-21 | 2020-12-21 | Conversion device for far infrared light polarization state |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202023088248.8U CN215910734U (en) | 2020-12-21 | 2020-12-21 | Conversion device for far infrared light polarization state |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215910734U true CN215910734U (en) | 2022-02-25 |
Family
ID=80285159
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202023088248.8U Active CN215910734U (en) | 2020-12-21 | 2020-12-21 | Conversion device for far infrared light polarization state |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN215910734U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112433383A (en) * | 2020-12-21 | 2021-03-02 | 江西万骏光电有限公司 | Far infrared light polarization state conversion device and implementation method |
-
2020
- 2020-12-21 CN CN202023088248.8U patent/CN215910734U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112433383A (en) * | 2020-12-21 | 2021-03-02 | 江西万骏光电有限公司 | Far infrared light polarization state conversion device and implementation method |
| CN112433383B (en) * | 2020-12-21 | 2024-04-05 | 江西万骏光电有限公司 | Far infrared light polarization state conversion device and implementation method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109669226B (en) | Laser radar scanning device based on super-surface lens group array and design method thereof | |
| CN102175376B (en) | Multi-laser-beam heterodyne micro-impulse-measuring device and method | |
| Strain et al. | Thermal lensing in recycling interferometric gravitational wave detectors | |
| CN107505705B (en) | Cross polarization conversion optical device and design method thereof | |
| CN110824187B (en) | Optical system for measuring angular velocity | |
| CN201653358U (en) | Novel linear diffraction grating interferometer structure | |
| CN215910734U (en) | Conversion device for far infrared light polarization state | |
| JPH0319482B2 (en) | ||
| CN102252794A (en) | Micro-impulse measuring method based on multi-beam laser heterodyne method and torsion pendulum method | |
| CN112433383B (en) | Far infrared light polarization state conversion device and implementation method | |
| CN103954392B (en) | What micro-momentum device was rocked in the measurement of linear frequency modulation multi-beam laser heterodyne rocks micro-impulse measurement method | |
| WO2022088334A1 (en) | Coherent laser radar | |
| CN214224366U (en) | Michelson interference type far infrared light polarization state conversion device | |
| US6115153A (en) | Reflection-type hologram scale and optical displacement measuring apparatus therewith | |
| CN109883553B (en) | Polarization measuring device and polarization measuring method | |
| Zhang et al. | A fully solid-state beam scanner for FMCW LiDAR application | |
| CN112577602A (en) | Michelson interference type far infrared light polarization state conversion device and implementation method | |
| CN110779456A (en) | Terahertz waveband super-surface phase shift device and measuring method thereof | |
| Palmer | Ultrasonic surface wave detection by optical interferometry | |
| CN108168703B (en) | Fourier transform spectrometer based on optical switch array and manufacturing method | |
| Pepper et al. | Double-pumped conjugators and photo-induced emf sensors: Two novel, high-bandwidth, auto-compensating, laser-based ultrasound detectors | |
| CN103968989A (en) | Device and method for measuring micro impulse by means of linear frequency modulation multi-beam laser heterodyne quadratic harmonic method and torsional pendulum method | |
| CN219179427U (en) | Remote measuring device for rotating speed of object | |
| US20220412719A1 (en) | Composite measurement system for measuring nanometer displacement | |
| CN103954391A (en) | Device and method for measuring micro-impulse based on linear frequency modulation multi-beam laser heterodyne quadratic harmonic method and torsional pendulum method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |