Terahertz light acting device and acting method

Abstract

The invention relates to a terahertz light acting device and method, and the device comprises a terahertz laser source which is used for outputting terahertz parallel beams; the visible light source is used for outputting and generating a visible guiding light beam, and the visible guiding light beam serves as guiding light of the terahertz parallel light beam; the light path adjusting system is used for combining the terahertz parallel light beams and the visible guide light beams to obtain combined light beams and converging the combined light beams; the thermal detection array is used for detecting a convergent light spot of the combined light after passing through the light path adjusting system; and the three-dimensional moving table is used for placing a to-be-acted sample and controlling the to-be-acted sample to move in the space. According to the invention, the control level of invisible terahertz light can be improved.

Description

Technical Field

[0001] The present invention relates to the field of terahertz technology, and in particular to a terahertz light action device and action method. Background Art

[0002] The interaction between terahertz (THz) light and matter reveals rich physical implications and novel phenomena. Terahertz quantum cascade lasers (QCLs) are very important radiation sources in the THz band, emitting laser frequencies in the 1-5 THz range and achieving maximum pulse powers in the watt range. THz QCLs have been widely used in research on THz communications, THz imaging, THz photoelectric measurement, and biomedical effects, making them an essential tool for studying the interaction between THz light and matter.

[0003] However, terahertz light is invisible to the naked eye, and due to the low energy of terahertz photons, thermal effect-based induction cards have difficulty displaying weak power signals well, resulting in poor terahertz optical path calibration. Therefore, in the optical path calibration of most terahertz systems, the role of thermal induction cards is limited, and they cannot achieve the same good optical path calibration effect as infrared light (the photon energy is about 30 times that of the terahertz frequency band).

[0004] To this end, in the 1-5THz frequency band, an accurate optical path calibration method is urgently needed to significantly improve the level of control over invisible terahertz light, so that when terahertz light interacts with matter, it can act on different local tiny areas of the sample, thereby demonstrating the diversity of the interaction areas between terahertz light and matter. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a terahertz light action device and action method, which can improve the control level of invisible terahertz light.

[0006] The technical solution adopted by the present invention to solve the technical problem is to provide a terahertz light action device, comprising:

[0007] A terahertz laser source, used for outputting a terahertz parallel beam;

[0008] A visible light source, configured to generate a visible guiding beam, wherein the visible guiding beam serves as a guiding light for the terahertz parallel beam;

[0009] an optical path adjustment system, configured to combine the terahertz parallel light beam and the visible guide light beam to obtain combined light, and to converge the combined light;

[0010] a thermal detection array, used to detect the convergent spot of the combined light after passing through the optical path adjustment system;

[0011] The three-dimensional moving stage is used to place the sample to be acted on and control the movement of the sample to be acted on in space.

[0012] The optical path adjustment system includes:

[0013] ITO conductive glass is used to reflect the terahertz parallel light beam and transmit the visible guide light beam, so that the terahertz parallel light beam and the visible guide light beam are combined to obtain combined light;

[0014] The off-axis parabolic reflector is used to collect and converge the combined light beam.

[0015] The surface of the ITO conductive glass forms an angle of 45 degrees with both the visible guide light beam and the terahertz parallel light beam.

[0016] The ITO conductive glass is a single-sided conductive glass.

[0017] The technical solution adopted by the present invention to solve the technical problem is: to provide a terahertz light action method, using the above-mentioned terahertz light action device, comprising the following steps:

[0018] Turning on the visible light source, and adjusting the position and pitch angle of the off-axis parabolic reflector in the optical path adjustment system so that the visible guide beam is irradiated on the center position of the off-axis parabolic reflector;

[0019] Adjusting the position of the thermal detection array so that the converging spot of the visible guide light beam reflected by the off-axis parabolic reflector is located at the center of the thermal detection array;

[0020] Turning on the terahertz laser source, adjusting the position of the terahertz laser source and the angle between the ITO conductive glass in the optical path adjustment system and the terahertz parallel beam, so that the converging spot of the terahertz parallel beam coincides with the spot of the visible guide beam;

[0021] Adjusting the position of the thermal detection array in the vertical direction, and recording the height of the sensing surface of the thermal detection array when the convergent spot of the terahertz parallel light beam reaches a minimum;

[0022] Turn off the terahertz laser source, turn on the visible light source, use the three-dimensional mobile stage to replace the thermal detection array, place the sample to be acted on the three-dimensional mobile stage, and adjust the height of the three-dimensional mobile stage so that the surface height of the sample to be acted on is consistent with the recorded height of the sensing surface of the thermal detection array;

[0023] Using the three-dimensional moving stage to adjust the two-dimensional position of the affected sample along the horizontal plane, so that the affected area of ​​the affected sample coincides with the light spot of the visible guiding light beam;

[0024] Turn on the terahertz laser source, measure the changes in various properties of the sample under the action of terahertz light according to the parameter settings, and obtain information on the interaction between terahertz light and matter.

[0025] Before turning off the terahertz laser source and turning on the visible light source, the method further comprises:

[0026] The visible light source and the terahertz laser source are turned off and on respectively, and it is confirmed that the center of the converging spot of the visible guide beam coincides with the center of the converging spot of the terahertz parallel beam.

[0027] After obtaining the information on the interaction between terahertz light and matter, the method further includes:

[0028] According to the size of the affected area of ​​the affected sample and the characteristic that the terahertz parallel beam is converged in the vertical direction, the height of the affected sample is adjusted using the three-dimensional moving stage to obtain the interaction information between the light spots of terahertz parallel beams of different sizes and the material.

[0029] Beneficial effects

[0030] Due to the adoption of the above-mentioned technical solution, the present invention has the following advantages and positive effects compared with the prior art: The present invention adopts a thermal detection array that responds to both visible light and terahertz light to perform common optical path adjustment and optical path calibration, and can simultaneously observe terahertz light and visible light at the same position. The present invention uses single-sided conductive ITO conductive glass to achieve both reflection of terahertz light and transmission of visible light by the entire glass, thereby very conveniently achieving common optical path adjustment of laser beams of two wavelength bands. The present invention places the sample on a three-dimensional moving stage to conduct experiments on the interaction between terahertz light and matter, which can not only obtain the optimal action accuracy close to the minimum spot size, but also achieve the interaction between terahertz spots of different sizes and matter by adjusting the height of the sample according to the size of the affected area. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 2. It is a schematic structural diagram of a terahertz light action device according to an embodiment of the present invention;

[0032] Figure 2 is a green light spot pattern measured by the thermal detection array in an embodiment of the present invention;

[0033] Figure 3 is a terahertz spot pattern measured by a thermal detection array in an embodiment of the present invention;

[0034] Figure 4 It is a normalized amplitude curve diagram at the center of the light spot when the terahertz light spot and the green light spot overlap in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0036] The embodiment of the present invention relates to a terahertz light action device, such as Figure 1 Shown, including:

[0037] A terahertz laser source 3 is configured to output a terahertz parallel beam 4 operating in a frequency range of 1 to 5 THz. The terahertz laser source 3 in this embodiment has a laser center frequency of 4.12 THz, corresponding to a wavelength of 72.9 μm and an output power of 2.6 mW.

[0038] A visible light source 1 is used to generate a visible guiding beam 2 with a low divergence angle, which serves as a guiding light for the terahertz parallel beam. In this embodiment, the visible light source 1 is a green light source with a laser wavelength of 532 nm and a beam diameter of 2 mm.

[0039] An optical path adjustment system is used to combine the terahertz parallel light beam and the visible guide light beam to obtain a combined light beam and converge the combined light beam. In this embodiment, the optical path adjustment system includes:

[0040] An ITO conductive glass 5, whose conductive surface is used to reflect the terahertz parallel light beam 4, and whose non-conductive surface is used to transmit the visible guide light beam 2, so that the terahertz parallel light beam 4 and the visible guide light beam 2 are combined to obtain a combined light beam 7; the surface of the ITO conductive glass 5 in this embodiment forms a 45-degree angle with the visible guide light beam 2 and the terahertz parallel light beam 4, and the ITO conductive glass 5 is a square single-sided conductive ITO conductive glass with a side length of 50 mm, a thickness of 1 mm, and a conductive surface resistivity of 10 Ω / sq;

[0041] An off-axis parabolic reflector 6 is used to collect and converge the combined light beam 7; the off-axis parabolic reflector 6 in this embodiment has a diameter of 50.8 mm and a focal length of 50.8 mm;

[0042] The thermal detection array 8 is used to detect the converged spot of the combined light after passing through the optical path adjustment system. In this embodiment, the pixel size of the thermal detection array 8 is 23.5 μm, and the pixel size is 320×240. The full width at half maximum of the center line of the converged terahertz light spot corresponds to 16 pixel sizes, which is 376 μm. The full width at half maximum of the center line of the green light spot at the same height of the thermal detection array corresponds to 15 pixel sizes, which is 352.5 μm. The two sizes are similar.

[0043] The three-dimensional moving stage 11 is used to place the sample 10 to be acted upon and control the movement of the sample 10 in the x, y, and z directions in space, so that the terahertz light acts on materials in different areas of the sample 10 to be acted upon. In this embodiment, the movement accuracy of the three-dimensional moving stage 11 in the x, y, and z directions is 10 μm, which can achieve an interaction accuracy between the terahertz light and the material close to the spot size (about 0.4 mm).

[0044] At the same time, this embodiment also proposes a terahertz light action method, which uses the above-mentioned terahertz light action device, and the specific implementation steps are as follows:

[0045] S1. Turn on the visible light source 1. The output visible guidance beam 2 with a low divergence angle passes through the ITO conductive glass 5 and reaches the off-axis parabolic reflector 6. Adjust the position and pitch angle of the off-axis parabolic reflector 6 so that the visible guidance beam 2 is irradiated at the center position of the off-axis parabolic reflector 6.

[0046] S2. Adjust the position of the thermal detection array 8 so that the converging spot of the visible guidance light beam 2 reflected by the off-axis parabolic reflector 6 is located at the center of the thermal detection array 8;

[0047] S3, turning on the terahertz laser source 3, the terahertz parallel beam 4 emitted by it is reflected by the conductive surface of the ITO conductive glass 5 and reaches the off-axis parabolic reflector 6, and then is reflected to the thermal detection array 8. By adjusting the position of the terahertz laser source 3 and the angle between the ITO conductive glass 5 and the terahertz parallel beam 4, the converging spot of the terahertz parallel beam 4 is made to coincide with the converging spot of the visible guide beam 2, that is, the converging spot 9 of the combined beam 7 is obtained;

[0048] S4. Adjust the position of the thermal detection array 8 in the vertical direction so that the convergent spot of the terahertz parallel beam 4 reaches the minimum, and record the height of the sensing surface of the thermal detection array 8 at this time;

[0049] S5. Turn off and on the visible light source 1 and the terahertz laser source 3 respectively, and confirm that the center of the converging spot of the visible guide beam 2 coincides with the center of the converging spot of the terahertz parallel beam 4. This step ensures that the centers of the converging spots of the lasers of the two wavelength bands coincide with each other. Figure 2 The green light spot measured by the thermal detection array is shown. Figure 3 The figure shows the terahertz light spot measured by the thermal detection array. Figure 4 Shown is the normalized amplitude curve at the center of the spot when the terahertz spot and the green light spot coincide;

[0050] Thus, the present invention employs a thermal detection array responsive to both visible and terahertz light for co-path adjustment and optical path calibration, enabling simultaneous observation of terahertz and visible light at the same location. The present invention also utilizes single-sided conductive ITO conductive glass to achieve both terahertz light reflection and visible light transmission, thus conveniently achieving co-path adjustment for laser beams of both wavelengths.

[0051] S6, turn off the terahertz laser source 3, turn on the visible light source 1, use the three-dimensional moving stage 11 to replace the thermal detection array, place the sample 10 on the three-dimensional moving stage 11, and adjust the height of the three-dimensional moving stage 11 so that the surface height of the sample 11 is consistent with the height of the sensing surface of the thermal detection array 8;

[0052] S7, using the three-dimensional moving stage 11 to adjust the two-dimensional position of the sample 10 along the horizontal plane, so that the affected area of ​​the sample 10 coincides with the converging spot of the visible guiding beam 2, which serves as the guiding light of the terahertz parallel light. At this time, the converging spot of the visible guiding beam 2 is the converging spot of the terahertz parallel light beam 4, that is, the position of the terahertz light irradiation;

[0053] S8, turning on the terahertz laser source 3, measuring the changes in various properties of the sample 10 under the action of the terahertz light according to the parameter settings, and obtaining information on the interaction between the terahertz light and the material;

[0054] S9. According to the size of the affected area of ​​the sample 10 and the characteristic that the terahertz light is concentrated in the vertical direction, the height of the affected sample 10 is adjusted by the three-dimensional moving stage 11 to obtain the interaction information between terahertz spots of different sizes and matter.

[0055] It is not difficult to find that the present invention places the sample on a three-dimensional moving stage to conduct the terahertz light-matter interaction experiment, which can not only obtain the optimal action accuracy close to the minimum spot size, but also realize the interaction between terahertz spots of different sizes and matter by adjusting the height of the sample according to the size of the affected area.

Claims

1. A terahertz light action device, characterized in that: include: A terahertz laser source, used for outputting a terahertz parallel beam; A visible light source, configured to generate a visible guiding beam, wherein the visible guiding beam serves as a guiding light for the terahertz parallel beam; an optical path adjustment system, configured to combine the terahertz parallel light beam and the visible guide light beam to obtain combined light, and to converge the combined light; a thermal detection array, used to detect the convergent spot of the combined light after passing through the optical path adjustment system; The three-dimensional moving stage is used to place the sample to be acted on and control the movement of the sample to be acted on in space.

2. The terahertz light action device according to claim 1, characterized in that: The optical path adjustment system includes: ITO conductive glass is used to reflect the terahertz parallel light beam and transmit the visible guide light beam, so that the terahertz parallel light beam and the visible guide light beam are combined to obtain combined light; The off-axis parabolic reflector is used to collect and converge the combined light beam.

3. The terahertz light action device according to claim 2, characterized in that: The surface of the ITO conductive glass forms an angle of 45 degrees with both the visible guide light beam and the terahertz parallel light beam.

4. The terahertz light action device according to claim 2, characterized in that: The ITO conductive glass is a single-sided conductive glass.

5. A terahertz light action method, characterized in that: The terahertz light action device according to any one of claims 1 to 4 comprises the following steps: Turning on the visible light source, and adjusting the position and pitch angle of the off-axis parabolic reflector in the optical path adjustment system so that the visible guide beam is irradiated on the center position of the off-axis parabolic reflector; Adjusting the position of the thermal detection array so that the converging spot of the visible guide light beam reflected by the off-axis parabolic reflector is located at the center of the thermal detection array; Turning on the terahertz laser source, adjusting the position of the terahertz laser source and the angle between the ITO conductive glass in the optical path adjustment system and the terahertz parallel beam, so that the converging spot of the terahertz parallel beam coincides with the spot of the visible guide beam; Adjusting the position of the thermal detection array in the vertical direction, and recording the height of the sensing surface of the thermal detection array when the convergent spot of the terahertz parallel light beam reaches a minimum; Turn off the terahertz laser source, turn on the visible light source, use the three-dimensional mobile stage to replace the thermal detection array, place the sample to be acted on the three-dimensional mobile stage, and adjust the height of the three-dimensional mobile stage so that the surface height of the sample to be acted on is consistent with the recorded height of the sensing surface of the thermal detection array; Using the three-dimensional moving stage to adjust the two-dimensional position of the affected sample along the horizontal plane, so that the affected area of ​​the affected sample coincides with the light spot of the visible guiding light beam; Turn on the terahertz laser source, measure the changes in various properties of the sample under the action of terahertz light according to the parameter settings, and obtain information on the interaction between terahertz light and matter.

6. The terahertz light action method according to claim 5, characterized in that: Before turning off the terahertz laser source and turning on the visible light source, the method further comprises: The visible light source and the terahertz laser source are turned off and on respectively, and it is confirmed that the center of the converging spot of the visible guide beam coincides with the center of the converging spot of the terahertz parallel beam.

7. The terahertz light action method according to claim 5, characterized in that: After obtaining the information on the interaction between terahertz light and matter, the method further includes: According to the size of the affected area of ​​the affected sample and the characteristic that the terahertz parallel beam is converged in the vertical direction, the height of the affected sample is adjusted using the three-dimensional moving stage to obtain the interaction information between the light spots of terahertz parallel beams of different sizes and the material.

Images