A transmissive and reflective probe and a terahertz time-domain spectroscopy system

Abstract

The present invention relates to the field of optoelectronic technology, and particularly to a transmissive and reflective dual-purpose probe and a terahertz time-domain spectroscopy system. The probe includes a first off-axis parabolic mirror, a second off-axis parabolic mirror, a first reserved test area disposed in a first direction of the second off-axis parabolic mirror, a third off-axis parabolic mirror, a fourth off-axis parabolic mirror, and a fifth off-axis parabolic mirror disposed in the negative Y-axis direction of the fourth off-axis parabolic mirror. A second reserved test area is provided on the optical path between the fourth off-axis parabolic mirror and the fifth off-axis parabolic mirror, and a sixth off-axis parabolic mirror reflects the terahertz wave from the fifth off-axis parabolic mirror to the terahertz receiving photoconductive antenna. By providing the transmissive and reflective dual-purpose probe, the present invention reduces resource waste, is simple to operate, can be used immediately after replacement, has strong adaptability, and can set a suitable probe type according to the optical path of the device.

Description

Technical Field

[0001] The present invention relates to the field of optoelectronic technologies, and particularly to a transmissive and reflective dual-purpose probe and a terahertz time-domain spectroscopy system. Background Art

[0002] Currently, terahertz detection systems have a wide range of applications and diverse measurement methods, including transmissive terahertz detection systems and reflective terahertz detection systems. However, the manufacturing technology of terahertz detection system devices in China is not perfect, making the cost of terahertz detection systems expensive. Therefore, the traditional one-device-for-one-use mode causes serious waste of resources, and the price of a single photoconductive antenna is as high as more than a hundred thousand yuan. Although the existing single-module multi-functional terahertz detection systems on the market can be used for multiple purposes, the test systems often have complex structures and difficult operations. When using different functions, users often need to manually adjust the internal devices to change the optical path of the system, which will reduce the stability of the terahertz detection system during the manual adjustment process and greatly affect its working efficiency. Summary of the Invention

[0003] An object of the present invention is to provide a transmissive and reflective dual-purpose probe to solve the above technical problems;

[0004] Another object of the present invention is to provide a transmissive and reflective dual-purpose terahertz time-domain spectroscopy system to solve the above technical problems.

[0005] The technical problems solved by the present invention can be achieved by the following technical solutions:

[0006] A transmissive and reflective dual-purpose probe includes:

[0007] A first off-axis parabolic mirror for reflecting the terahertz waves diverging in the positive X-axis direction emitted by a terahertz emission photoconductive antenna into parallel terahertz waves in the positive Z-axis direction;

[0008] A second off-axis parabolic mirror is disposed in the positive Z-axis direction of the first off-axis parabolic mirror for reflecting the terahertz waves from the first off-axis parabolic mirror in a first direction between the negative Z-axis direction and the negative Y-axis direction;

[0009] A first reserved test area is disposed in the first direction of the second off-axis parabolic mirror;

[0010] A third off-axis parabolic mirror is disposed in a second direction between the positive Y-axis direction and the negative Z-axis direction of the first reserved test area for reflecting the terahertz waves from the first reserved test area in the positive Z-axis direction;

[0011] A fourth off-axis parabolic mirror is disposed in the positive Z-axis direction of the third off-axis parabolic mirror for reflecting the terahertz waves from the third off-axis parabolic mirror in the negative Y-axis direction;

[0012] The fifth off-axis parabolic mirror is arranged in the negative Y-axis direction of the fourth off-axis parabolic mirror. A second reserved test area is provided on the optical path between the fourth off-axis parabolic mirror and the fifth off-axis parabolic mirror. The fifth off-axis parabolic mirror is used to reflect the terahertz wave from the fourth off-axis parabolic mirror in the negative Z-axis direction;

[0013] The sixth off-axis parabolic mirror is arranged in the negative Z-axis direction of the fifth off-axis parabolic mirror and is used to reflect the terahertz wave from the fifth off-axis parabolic mirror to the terahertz receiving photoconductive antenna.

[0014] Preferably, there is a first distance between the centers of the second off-axis parabolic mirror and the first off-axis parabolic mirror, a second distance between the first reserved test area and the center of the second off-axis parabolic mirror, a third distance between the third off-axis parabolic mirror and the first reserved test area, a fourth distance between the centers of the fourth off-axis parabolic mirror and the third off-axis parabolic mirror, a fifth distance between the second reserved test area and the center of the fourth off-axis parabolic mirror, a sixth distance between the fifth off-axis parabolic mirror and the second reserved test area, and a seventh distance between the centers of the sixth off-axis parabolic mirror and the fifth off-axis parabolic mirror.

[0015] Preferably, a sample to be measured is provided on the first reserved test area.

[0016] Preferably, an elliptical reflector is provided on the first reserved test area, and a sample to be measured is provided on the second reserved test area.

[0017] Preferably, the second reserved test area is arranged at the intersection of the optical paths between the fourth off-axis parabolic mirror and the fifth off-axis parabolic mirror.

[0018] Preferably, based on the focus of the sixth off-axis parabolic mirror, there is a set distance between the focus of the sixth off-axis parabolic mirror and the terahertz receiving photoconductive antenna.

[0019] Preferably, the first reserved test area is a reflection sample test area, and the second reserved test area is a transmission sample test area.

[0020] Preferably, the first direction and the second direction have the same included angle with the Y-axis.

[0021] A terahertz time-domain spectroscopy system for both transmission and reflection includes,

[0022] A femtosecond fiber laser that outputs a pump light and a probe light;

[0023] The terahertz emission photoconductive antenna is connected to the femtosecond laser through a first optical fiber, receives the pump light, and generates incident terahertz waves under the excitation of the pump light;

[0024] The transmissive and reflective probe receives the incident terahertz waves and generates output terahertz waves carrying information of the sample to be measured;

[0025] The terahertz receiving photoconductive antenna receives the probe light and the output terahertz waves carrying information of the sample to be measured, converts the optical signal into an electrical signal, and outputs the information of the sample to be measured.

[0026] Preferably, the terahertz receiving photoconductive antenna is connected to the femtosecond laser through a second optical fiber and a third optical fiber, receives the probe light and the output terahertz waves carrying information of the sample to be measured, converts the optical signal into an electrical signal, and outputs the information of the sample to be measured; an optical delay line for changing the optical path of the probe light is provided between the second optical fiber and the third optical fiber.

[0027] Advantages of the present invention: Due to the above technical solutions, by providing a transmissive and reflective probe, the present invention reduces resource waste, is simple to operate, can be replaced and used at any time, has strong adaptability, and can set a suitable probe type according to the optical path of the device. Description of the Drawings

[0028] Figure 1 It is a schematic diagram of the reflection structure of the transmissive and reflective probe in the embodiment of the present invention;

[0029] Figure 2 It is a schematic diagram of the transmission structure of the transmissive and reflective probe in the embodiment of the present invention;

[0030] Figure 3 It is a schematic diagram of the terahertz time-domain spectroscopy system in the embodiment of the present invention. Detailed Embodiments

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0033] Next, the present invention will be further described in conjunction with the drawings and specific embodiments, but it is not a limitation of the present invention.

[0034] A transmissive and reflective probe, as Figure 1 , Figure 2 shown, includes

[0035] The first off-axis parabolic mirror 1 reflects the terahertz waves diverging in the positive X-axis direction emitted by the terahertz emission photoconductive antenna 106 into parallel terahertz waves in the positive Z-axis direction;

[0036] The second off-axis parabolic mirror 2 is arranged on the positive Z-axis direction of the first off-axis parabolic mirror 1 and is used to reflect the terahertz waves from the first off-axis parabolic mirror 1 in a first direction between the negative Z-axis direction and the negative Y-axis direction;

[0037] The first reserved test area is arranged in the first direction of the second off-axis parabolic mirror;

[0038] The third off-axis parabolic mirror 4 is arranged in a second direction between the positive Y-axis direction and the negative Z-axis direction of the first reserved test area and is used to reflect the terahertz waves from the first reserved test area in the positive Z-axis direction;

[0039] The fourth off-axis parabolic mirror 5 is arranged on the positive Z-axis direction of the third off-axis parabolic mirror 4 and is used to reflect the terahertz waves from the third off-axis parabolic mirror 4 in the negative Y-axis direction;

[0040] The fifth off-axis parabolic mirror 7 is arranged on the negative Y-axis direction of the fourth off-axis parabolic mirror 5. A second reserved test area is arranged on the optical path between the fourth off-axis parabolic mirror 5 and the fifth off-axis parabolic mirror 7. The fifth off-axis parabolic mirror 7 is used to reflect the terahertz waves from the fourth off-axis parabolic mirror 5 in the negative Z-axis direction;

[0041] The sixth off-axis parabolic mirror 8 is arranged on the negative Z-axis direction of the fifth off-axis parabolic mirror 7 and is used to reflect the terahertz waves from the fifth off-axis parabolic mirror 7 to the terahertz receiving photoconductive antenna 107.

[0042] Specifically, the present invention can select to place a test sample in either the first reserved test area or the second reserved test area, which can quickly realize the switching of the probe function. Preferably, the transmissive and reflective probe provided by the present invention can be used for multiple purposes, reducing resource waste; it is simple to operate, can be used immediately after replacement, and will not affect the stability of the terahertz detection system. It has strong adaptability and can design a suitable transmissive probe or reflective probe according to the optical path of the device. For researchers considering using a dual-purpose probe, it is a simple, ideal, and feasible design method, which provides more choices for users on the premise of saving costs. In the prior art, if an independent probe is used, adding a measurement method requires adding more than 100,000 yuan of photoconductive antennas and optical elements. Using this dual-purpose probe design method, adding a measurement method only requires adding an elliptical mirror and adjusting the position of the test sample. The inserted elements are few, the optical path is short, and the introduced loss is small.

[0043] In a preferred embodiment, there is a first distance between the centers of the second off-axis parabolic mirror 2 and the first off-axis parabolic mirror 1, a second distance between the first reserved test area and the center of the second off-axis parabolic mirror 2, a third distance between the third off-axis parabolic mirror 4 and the first reserved test area, a fourth distance between the centers of the fourth off-axis parabolic mirror 5 and the third off-axis parabolic mirror 4, a fifth distance between the second reserved test area and the center of the fourth off-axis parabolic mirror 5, a sixth distance between the fifth off-axis parabolic mirror 7 and the second reserved test area, and a seventh distance between the centers of the sixth off-axis parabolic mirror 8 and the fifth off-axis parabolic mirror 7.

[0044] In a preferred embodiment, please further refer to Figure 1 As shown, a sample to be tested 16 is provided on the first reserved test area.

[0045] Specifically, in this embodiment, the terahertz photoconductive antenna emits terahertz waves diverging in the positive X-axis direction. The terahertz waves are reflected by the first off-axis parabolic mirror 1 into parallel terahertz waves and are reflected by the second off-axis parabolic mirror 2 at a distance of the first distance from the center of the first parabolic mirror in the positive Z-axis direction. The reflected terahertz waves are focused on the sample to be tested 16 at a distance of the second distance from the center of the second off-axis parabolic mirror 2 in the first direction between the negative Z-axis direction and the negative Y-axis direction and carry the sample information and are reflected again. The reflected terahertz waves are reflected by the third off-axis parabolic mirror 4 at a distance of the third distance from the sample to be tested 16 in the second direction between the positive Y-axis direction and the negative Z-axis direction into parallel light. The reflected terahertz waves are reflected again by the fourth off-axis parabolic mirror 5 at a distance of the fourth distance from the third off-axis parabolic mirror 4 in the positive Z-axis direction. The reflected terahertz waves are focused in the negative Y-axis direction at a distance of the fifth distance from the fourth off-axis parabolic mirror 5. The terahertz waves diverge in the negative Y-axis direction and reach the fifth off-axis parabolic mirror 7 at a distance of the sixth distance from the second reserved test area and are reflected into parallel light. The parallel light is reflected by the sixth off-axis parabolic mirror 8 at a distance of the seventh distance from the fifth off-axis parabolic mirror 7 in the negative Z-axis direction and is focused on the terahertz receiving antenna. In this embodiment, the distances between the optical elements can be adjusted according to the focal length of the off-axis parabolic mirror and the size of the optical structural members.

[0046] In a preferred embodiment, please further refer to Figure 2 As shown, an elliptical mirror 3 is provided on the first reserved test area, and a sample to be tested 6 is provided on the second reserved test area.

[0047] Specifically, the terahertz photoconductive antenna emits terahertz waves diverging in the positive X-axis direction. The terahertz waves are reflected by the first off-axis parabolic mirror 1 into parallel terahertz waves, and then reflected by the second off-axis parabolic mirror 2 at a first distance from the center of the first parabolic mirror along the positive Z-axis direction. The reflected terahertz waves are focused and reflected again by the elliptical mirror at a second distance from the center of the second off-axis parabolic mirror 2 in the first direction between the negative Z-axis direction and the negative Y-axis direction. The reflected terahertz waves are reflected by the third off-axis parabolic mirror 4 at a third distance from the elliptical mirror 3 in the second direction between the positive Y-axis direction and the negative Z-axis direction into parallel light. The reflected terahertz waves are reflected again by the fourth off-axis parabolic mirror 5 at a fourth distance from the third off-axis parabolic mirror 4 along the positive Z-axis direction. The reflected terahertz waves are focused in the negative Y-axis direction on the sample under test 6 at a fifth distance from the fourth off-axis parabolic mirror 5. The terahertz waves penetrate the sample under test 6 and carry the sample information to reach the fifth off-axis parabolic mirror 7 at a sixth distance from the sample under test in the negative Y-axis direction and are reflected into parallel light. The parallel light is reflected and focused by the sixth off-axis parabolic mirror 8 at a seventh distance from the fifth off-axis parabolic mirror 7 along the negative Z-axis direction to the terahertz receiving antenna. In this embodiment, the distances between the optical elements can be adjusted according to the focal length of the off-axis parabolic mirror and the size of the optical structure members.

[0048] In a preferred embodiment, the second reserved test area is arranged at the optical path intersection between the fourth off-axis parabolic mirror 5 and the fifth off-axis parabolic mirror 7.

[0049] In a preferred embodiment, based on the focus of the sixth off-axis parabolic mirror 8, there is a set distance between the focus of the sixth off-axis parabolic mirror 8 and the terahertz receiving photoconductive antenna 107.

[0050] In a preferred embodiment, the first direction and the second direction have the same angle with the Y-axis. The first direction is the incident angle direction of the terahertz waves in the first reserved test area, and the second direction is the exit angle direction of the terahertz waves in the first reserved test area. The first direction and the second direction are symmetrically arranged along the Y-axis.

[0051] In a preferred embodiment, the first reserved test area is a reflection sample test area, and the second reserved test area is a transmission sample test area.

[0052] A terahertz time-domain spectroscopy system for both transmission and reflection, as Figure 3 shown, includes,

[0053] A femtosecond fiber laser 101, which outputs a pump light and a probe light;

[0054] A terahertz emission photoconductive antenna 106, which is connected to the femtosecond fiber laser 101 through a first optical fiber 102, receives the pump light, and generates incident terahertz waves under the excitation of the pump light;

[0055] The transmissive and reflective probe 108 in any one of the embodiments receives the incident terahertz wave and generates an output terahertz wave carrying the information of the sample to be measured;

[0056] The terahertz receiving photoconductive antenna 107 receives the probe light and the output terahertz wave carrying the information of the sample to be measured, converts the optical signal into an electrical signal, and outputs the information of the sample to be measured.

[0057] In a preferred embodiment, the terahertz receiving photoconductive antenna 107 is connected to the femtosecond fiber laser 101 through a second optical fiber 103 and a third optical fiber 104, receives the probe light and the output terahertz wave carrying the information of the sample to be measured, converts the optical signal into an electrical signal, and outputs the information of the sample to be measured; an optical delay line 105 for changing the optical path of the probe light is provided between the second optical fiber 103 and the third optical fiber 104.

[0058] In a preferred embodiment, the adjustment method of the transmissive and reflective probe of the present invention is as follows.

[0059] When performing a reflection test, place the sample to be measured in the first reserved test area and remove the sample to be measured placed in the second reserved test area;

[0060] When performing a transmission test, place an elliptical mirror in the first reserved test area and place the sample to be measured in the second reserved test area.

[0061] The above are only the preferred embodiments of the present invention, and do not limit the implementation manners and protection scope of the present invention. For those skilled in the art, it should be understood that any equivalent replacement and obvious changes made by using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A transmissive and reflective dual-purpose probe for a terahertz time-domain spectroscopy system, characterized in that Including, A first off-axis parabolic mirror for reflecting the terahertz waves diverging in the positive X-axis direction emitted by the terahertz-emitting photoconductive antenna into parallel terahertz waves in the positive Z-axis direction; A second off-axis parabolic mirror disposed on the positive Z-axis direction of the first off-axis parabolic mirror for reflecting the terahertz waves from the first off-axis parabolic mirror in a first direction between the negative Z-axis direction and the negative Y-axis direction; A first reserved test area disposed in the first direction of the second off-axis parabolic mirror; A third off-axis parabolic mirror disposed in a second direction between the positive Y-axis direction and the negative Z-axis direction of the first reserved test area for reflecting the terahertz waves from the first reserved test area in the positive Z-axis direction; A fourth off-axis parabolic mirror disposed on the positive Z-axis direction of the third off-axis parabolic mirror for reflecting the terahertz waves from the third off-axis parabolic mirror in the negative Y-axis direction; A fifth off-axis parabolic mirror disposed on the negative Y-axis direction of the fourth off-axis parabolic mirror, with a second reserved test area provided on the optical path between the fourth off-axis parabolic mirror and the fifth off-axis parabolic mirror, and the fifth off-axis parabolic mirror for reflecting the terahertz waves from the fourth off-axis parabolic mirror in the negative Z-axis direction; A sixth off-axis parabolic mirror disposed on the negative Z-axis direction of the fifth off-axis parabolic mirror for reflecting the terahertz waves from the fifth off-axis parabolic mirror to the terahertz-receiving photoconductive antenna; Selectively place a sample to be tested in either the first reserved test area or the second reserved test area.

2. The transflective probe according to claim 1, wherein There is a first distance between the centers of the second off-axis parabolic mirror and the first off-axis parabolic mirror, a second distance between the center of the first reserved test area and the second off-axis parabolic mirror, a third distance between the third off-axis parabolic mirror and the first reserved test area, a fourth distance between the centers of the fourth off-axis parabolic mirror and the third off-axis parabolic mirror, a fifth distance between the center of the second reserved test area and the fourth off-axis parabolic mirror, a sixth distance between the fifth off-axis parabolic mirror and the second reserved test area, and a seventh distance between the centers of the sixth off-axis parabolic mirror and the fifth off-axis parabolic mirror.

3. The transflective probe according to claim 1, characterized in that, A sample to be tested is provided on the first reserved test area.

4. The transflective probe according to claim 1, wherein An elliptical mirror is provided on the first reserved test area, and a sample to be tested is provided on the second reserved test area.

5. The transflective probe according to claim 1, wherein, The second reserved test area is disposed at the intersection of the optical paths between the fourth off-axis parabolic mirror and the fifth off-axis parabolic mirror.

6. The transflective probe according to claim 1, wherein Based on the focus of the sixth off-axis parabolic mirror, there is a set distance between the focus of the sixth off-axis parabolic mirror and the terahertz-receiving photoconductive antenna.

7. The transflective probe according to claim 1, wherein The first reserved test area is a reflection sample test area, and the second reserved test area is a transmission sample test area.

8. The transflective probe according to claim 1, wherein The first direction and the second direction have the same angle with the Y-axis.

9. A transmissive and reflective terahertz time-domain spectroscopy system, characterized in that, Including, A femtosecond fiber laser that outputs a pump light and a probe light; The terahertz emission photoconductive antenna is connected to the femtosecond laser through a first optical fiber, receives the pump light, and generates incident terahertz waves under the excitation of the pump light; The transmissive and reflective probe according to any one of claims 1-8, wherein the transmissive and reflective probe receives the incident terahertz waves and generates output terahertz waves carrying information of the sample to be measured; The terahertz receiving photoconductive antenna receives the probe light and the output terahertz waves carrying information of the sample to be measured, converts the optical signal into an electrical signal, and outputs the information of the sample to be measured.

10. The transmissive and reflective terahertz time-domain spectroscopy system according to claim 9, wherein, The terahertz receiving photoconductive antenna is connected to the femtosecond laser through a second optical fiber and a third optical fiber, receives the probe light and the output terahertz waves carrying information of the sample to be measured, converts the optical signal into an electrical signal, and outputs the information of the sample to be measured; an optical delay line for changing the optical path of the probe light is provided between the second optical fiber and the third optical fiber.

Images