A stabilization control system and method for a terahertz dual-comb spectrometer

Abstract

This invention relates to the field of terahertz wave technology, specifically to a stable control system and method for a terahertz dual-comb spectrometer. The method includes the following steps: S1, using a first femtosecond optical comb and a second femtosecond optical comb with a difference in repetition frequency as laser sources; S2, coupling the low-energy femtosecond light output from the first femtosecond optical comb into a first F-P cavity, and coupling the low-energy femtosecond light output from the second femtosecond optical comb into a second F-P cavity; coupling a first modulation light and a second modulation light into the first F-P cavity and the second F-P cavity, respectively; S3, coupling the light output from the first femtosecond optical comb and the second femtosecond optical comb to a photodetector to acquire a first beat frequency signal; S4, extracting frequency jitter information from the first beat frequency signal, processing it, and using it as an adaptive sampling clock signal for a data acquisition card; S5, performing negative feedback adjustment control based on the photoelectric conversion information of the first F-P cavity and the second F-P cavity. This invention solves the problem that existing THz dual-comb systems are difficult to achieve long-term stable operation.

Description

Technical Field

[0001] This invention relates to the field of terahertz wave technology, specifically to a terahertz dual-comb spectrometer stabilization control system and method. Background Technology

[0002] Terahertz (THz) radiation refers to electromagnetic waves with frequencies ranging from 0.1 to 10 THz and wavelengths covering 0.03 to 3 mm. Due to the strong vibrational and rotational resonant absorption of many molecules within this frequency range, the THz band holds significant importance in spectral analysis and imaging. Therefore, achieving high-precision, long-term stable THz optical comb spectrum generation and detection is essential, providing technical support for the application of THz technology in various fields. THz dual-comb spectral detection is a high-precision THz spectral detection method developed in recent years. This method does not require a mechanical delay line and can achieve THz time-domain signal detection through THz pulse self-scanning, thus offering significant advantages in spectral resolution and single-sampling time. However, during the stabilization process of the THz dual-comb, the phase-locked and frequency-locked systems in the comb have high environmental requirements, and factors such as mechanical jitter noise and thermal noise can increase the system's instability, directly limiting the long-term stability of the dual-comb system and making it highly susceptible to THz spectral drift.

[0003] To overcome the above problems, a long-term stable control method for a THz dual-comb spectrometer is proposed. Summary of the Invention

[0004] One of the objectives of this invention is to provide a stable control system for a terahertz dual-comb spectrometer, which solves the problem that existing THz dual-comb systems are difficult to operate stably for a long period of time.

[0005] To achieve the above objectives, a stabilization and control system for a terahertz dual-comb spectrometer is provided, comprising the following steps:

[0006] S1. Use two femtosecond optical combs with a difference in repetition frequency as laser sources;

[0007] S2. Couple the low-energy femtosecond light output from the first femtosecond optical comb into the first FP cavity, and couple the low-energy femtosecond light output from the second femtosecond optical comb into the second FP cavity.

[0008] The light output from the continuous laser is input into the first electro-optic modulator and the second electro-optic modulator respectively to obtain the first modulated light and the second modulated light respectively, and the first modulated light and the second modulated light are coupled into the first FP cavity and the second FP cavity respectively.

[0009] S3. Couple the w1 light output from the first FP cavity and the w2 light output from the second FP cavity to the photodetector PD-1 to obtain the first beat frequency signal;

[0010] S4. Extract frequency jitter information containing the first femtosecond optical comb and the second femtosecond optical comb based on the first beat frequency signal, perform data processing based on the frequency jitter information, and use the data processing result as the adaptive sampling clock signal for the data acquisition card to acquire THz data of the first femtosecond optical comb and the second femtosecond optical comb.

[0011] S5. Obtain the photoelectric conversion information of the w1 light output from the first FP cavity and the w2 light output from the second FP cavity, respectively, and perform negative feedback adjustment control on the first femtosecond optical comb and the second femtosecond optical comb according to the photoelectric conversion information.

[0012] Furthermore, the negative feedback adjustment control in step S5 specifically includes the following steps:

[0013] S501. Input the w1 light output from the first FP cavity into the first photodetector, convert it into a first electrical signal, and control the first femtosecond optical comb based on the feedback of the first electrical signal.

[0014] S502, input the w2 light output from the second FP cavity to the second photodetector, convert it into a second electrical signal, and control the second femtosecond optical comb based on the feedback of the second electrical signal.

[0015] Furthermore, the feedback control specifically includes the following steps:

[0016] S503. Determine whether the voltage measured by the first photodetector / second photodetector is lower than the set voltage value. If it is lower, increase the PZT driving voltage in the first FP cavity / second FP cavity to lengthen the femtosecond optical comb resonant cavity and increase the repetition frequency. f r Get smaller;

[0017] S504. Next, determine whether the voltage measured by the first photodetector / second photodetector has increased. If it has increased, continue to increase the PZT driving voltage to lengthen the femtosecond optical comb resonant cavity and increase the repetition frequency. f r The voltage is reduced until the voltage measured by the first photodetector / second photodetector is not lower than the set voltage value; if it decreases further, the PZT driving voltage is reduced to shorten the cavity length and increase the repetition frequency. f r Increase until the voltage measured by the first photodetector / second photodetector is not lower than the set voltage value.

[0018] Furthermore, step S2 also includes the following steps:

[0019] S201. Input the high-energy femtosecond light output from the first femtosecond optical comb into the first photoconductive antenna, and input the high-energy femtosecond light output from the second femtosecond optical comb into the second photoconductive antenna.

[0020] S202. The THz optical comb generated by the first photoconductive antenna is transmitted to the second photoconductive antenna to obtain a current signal reflecting the THz electric field, and the current signal is input to the data acquisition card.

[0021] Furthermore, step S2 also includes the following steps:

[0022] S203. Input the light output from the continuous laser into the third photodetector and the fourth photodetector respectively;

[0023] S204. Input the low-energy femtosecond light output from the first femtosecond optical comb into the third photodetector to obtain the second beat frequency signal;

[0024] S205. Input the low-energy femtosecond light output from the second femtosecond optical comb into the fourth photodetector to obtain the third beat frequency signal;

[0025] S206. The second beat frequency signal and the third beat frequency signal are mixed by the first mixer to obtain the first mixed electrical signal.

[0026] Furthermore, the data processing in the aforementioned steps includes the following steps:

[0027] S401. The first beat frequency signal and the first mixing electrical signal are mixed by the second mixer to obtain the second mixing electrical signal, and the second mixing electrical signal is used as the new adaptive sampling clock signal and input to the data acquisition card.

[0028] Furthermore, the first and second femtosecond optical combs are two femtosecond laser sources with a fixed difference in repetition frequency and a pulse width on the order of hundreds of fs. Their repetition frequency and carrier envelope phase are respectively... f r1 , f cep1 and f r2 , f cep2 , f r2 = f r1 +∆ f r , ∆ f r This represents the difference in repetition frequency between the two femtosecond optical combs.

[0029] Furthermore, the length of the first FP cavity is h 1. The length of the second FP cavity is h 2. Both the first FP cavity and the second FP cavity include two parallel plates with high reflectivity disposed on piezoelectric ceramics; the first modulated light is coupled into the first FP cavity at a zero-degree incident angle, and its cavity length satisfies 100m.f r1 + f cep1 = kc / 2 nh 1. The second modulated light is coupled into the second FP cavity at a zero-degree incident angle, and the cavity length satisfies 100m. f r2 + f cep2 = kc / 2 nh 2, of which k It is an integer. c At the speed of light, n The refractive index of air is 100m, which represents the 100mth tooth of the first and second femtosecond optical combs mentioned above.

[0030] Furthermore, the w1 and w2 beams are two narrow-linewidth light sources;

[0031] w1=m(100) f r1 )+ f cep1 w2=m(100) f r2 )+ f cep2

[0032] Among them, 100 f r1 The modulation frequency of the first electro-optic modulator is 100. f r2 This is the modulation frequency of the second electro-optic modulator.

[0033] The second objective of this invention is to provide a stable control system for a terahertz dual-comb spectrometer. The system is constructed using the above-mentioned method and includes two femtosecond optical combs with different repetition frequencies, several photoelectric detection modules, a continuous laser, two electro-optic modulators, two FP cavities, a first photoconductive antenna and a second photoconductive antenna, a feedback control module, an adaptive clock extraction module, and a data acquisition card.

[0034] Principles and advantages:

[0035] 1. By employing continuous photoelectric modulation and Fabry-Perot (FP) cavity resonance transmission enhancement, this method adaptively compensates for the repetition frequency jitter of two femtosecond optical combs using continuous optical beat frequency. Furthermore, active feedback compensation traces the femtosecond optical comb repetition frequency feedback control back to the same continuous light source, thereby obtaining a high-precision and long-term stable THz spectrum. Compared to previous adaptive control schemes, this scheme uses the same continuous light source for its adaptive clock signal, requiring only one continuous light source to extract the repetition frequency jitter of both femtosecond optical combs, significantly simplifying the system and increasing its integration.

[0036] 2. By combining the high stability of electro-optic modulation with the low intensity of FP cavity and phase noise feedback control, two femtosecond optical combs are locked on different high-order modes of the same continuous light, resulting in high system coherence and improved femtosecond optical comb feedback control accuracy and long-term stability.

[0037] 3. The femtosecond optical comb active feedback control ensures that the system operates within a suitable bandwidth range, improving the long-term stability of the system. Attached Figure Description

[0038] Figure 1 This is a schematic diagram illustrating the principle of a terahertz dual-comb spectrometer stabilization control system according to an embodiment of the present invention.

[0039] Figure 2 This is a flowchart for feedback control. Detailed Implementation

[0040] The following detailed description illustrates the specific implementation method:

[0041] The reference numerals in the accompanying drawings include: femtosecond optical comb 1, femtosecond optical comb 2, first photoconductive antenna PCA1, second photoconductive antenna PCA2, data acquisition card DAP, first electro-optic modulator EOM1, second electro-modulator EOM2, FP cavity 1, FP cavity 2, photodetector PD-1, first photodetector PD1, second photodetector PD2, third photodetector PD3, fourth photodetector PD4, first mixer M1, and second mixer M2.

[0042] Example

[0043] A method for stabilizing and controlling a terahertz dual-comb spectrometer, basically as follows: Figure 1 , Figure 2 As shown, the specific steps include:

[0044] S1, connect two femtosecond optical combs with a difference in repetition frequency ( Figure 1 The second femtosecond optical comb (abbreviated as femtosecond optical comb 1) and the second femtosecond optical comb (abbreviated as femtosecond optical comb 2) Figure 1The first and second femtosecond optical combs are two femtosecond laser sources with a fixed difference in repetition frequency and a pulse width on the order of hundreds of fs. Their repetition frequency and carrier envelope phase are respectively... f r1 , f cep1 and f r2 , f cep2 , f r2 = f r1 +∆ f r , ∆ f r This represents the difference in repetition frequency between the two femtosecond optical combs.

[0045] S2 includes the following sub-steps:

[0046] S200, make the first femtosecond optical comb 1 output a high-energy femtosecond light beam and two low-energy femtosecond light beams, and make the second femtosecond optical comb 2 output a high-energy femtosecond light beam and two low-energy femtosecond light beams;

[0047] S201. Input the high-energy femtosecond light output from the first femtosecond optical comb 1 into the first photoconductive antenna PCA1, and input the high-energy femtosecond light output from the second femtosecond optical comb 2 into the second photoconductive antenna PCA2.

[0048] S202. The THz optical comb generated by the first photoconductive antenna PCA1 is transmitted to the second photoconductive antenna PCA2 to obtain a current signal reflecting the THz electric field, and the current signal is input to the data acquisition card DAP.

[0049] S203, The light output from a continuous laser with a wavelength approximately equal to the center wavelength of two femtosecond optical combs (frequency is...) f cw The beam is split into two beams by a beam splitter and input to the first electro-optic modulator EOM1 and the second electro-optic modulator EOM2, respectively, to obtain the first modulated light and the second modulated light. The modulation frequency of the first electro-optic modulator EOM1 is 100. f r1 After electrical modulation, the output repetition frequency is 100. f r1 The light beam, referred to as the first modulated light, is coupled into FP cavity 1; another beam of light is input into the second electrical modulator EOM2, whose modulation frequency is 100 Hz. f r2 That is, 100 ( f r1 +∆ f rAfter passing through the electro-optic modulator, the output repetition frequency is 100. f r2 The light that is modulated is called the second modulated light.

[0050] S204, Couple one of the low-energy femtosecond beams output from the first femtosecond optical comb into the first FP cavity (corresponding to...). Figure 1 The FP cavity 1) couples one of the low-energy femtosecond beams output from the second femtosecond optical comb into the second FP cavity (corresponding to Figure 1 FP cavity 2);

[0051] The length of the first FP cavity is h 1. The length of the second FP cavity is h 2. The first FP cavity comprises two highly reflective parallel plates H1 and M1' disposed on piezoelectric ceramics, and the second FP cavity comprises two highly reflective parallel plates H2 and M2 disposed on piezoelectric ceramics. Since both the first FP cavity (FP cavity 1) and the second FP cavity (FP cavity 2) are Fabry-Perot interference cavities with tunable cavity lengths, the cavity length of FP cavity 1 can be tuned by applying different voltages to the piezoelectric ceramics. h Cavity lengths of 1 and FP 2 h 2. The light coupled into FP cavity 1 or FP cavity 2 undergoes multiple reflections within the cavity before being output. The first modulated light is coupled into FP cavity 1 at a zero-degree incident angle, and its cavity length satisfies 100m. f r1 + f cep1 = kc / 2 nh 1. The second modulated light is coupled into the FP cavity 2 at a zero-degree incident angle, and the cavity length satisfies 100m. f r2 + f cep2 = kc / 2 nh 2, of which k It is an integer. c At the speed of light, n The refractive index of air is 100m, which represents the 100mth tooth of the first and second femtosecond optical combs mentioned above.

[0052] S210, then the light output from the continuous laser (frequency is...) f cw The signals are respectively input to the third photodetector PD3 and the fourth photodetector PD4;

[0053] S220. The second low-energy femtosecond light output from the first femtosecond optical comb 1 is input into the third photodetector PD3 to obtain the second beat frequency signal k. f r1 +f cep1 ;

[0054] S220, the second low-energy femtosecond light output from the second femtosecond optical comb 2 is input into the fourth photodetector PD4 to obtain the third beat frequency signal k. f r2 + f cep2 ;

[0055] S240. The second beat frequency signal and the third beat frequency signal are mixed by the first mixer M1 to obtain the first mixed electrical signal.

[0056] k ∆ f r +∆ f cep .

[0057] Steps S201 and S202, step S203, and steps S210, S220, S230, and S240 can be executed in parallel.

[0058] S3. Couple the w1 light output from the first FP cavity and the w2 light output from the second FP cavity to the photodetector PD-1 to obtain the first beat frequency signal and first beat frequency information. f beat =w2-w1=100m∆ f r +∆ f cep , where ∆ f cep The phase difference between the carrier envelopes of the two femtosecond optical combs is denoted as .

[0059] S4. Extract frequency jitter information containing the first and second femtosecond optical combs based on the first beat frequency signal; perform data processing based on the frequency jitter information; and use the data processing result as the adaptive sampling clock signal for the data acquisition card to acquire THz data from the first and second femtosecond optical combs; first beat frequency signal f beat =w2-w1=100m∆ f r +∆ f cep , where ∆ f cep The carrier envelope phase difference between the two femtosecond optical combs. The data processing in step S4 specifically includes the following steps:

[0060] S401, Combine the first beat frequency signal and the first mixing frequency signal k∆ f r +∆ f cepThe signal is mixed by the second mixer M2 to obtain a second mixed electrical signal, which is then used as the adaptive sampling clock signal n∆ of the data acquisition card. f r The data acquisition card (DAP) uses an adaptive sampling clock signal n∆ f r For example, the DAP data acquisition card can collect the current signal reflecting the THz electric field obtained by the second photoconductive antenna PCA2 several times per second or once every few seconds.

[0061] S5. Obtain the photoelectric conversion information of the w1 light output from the first FP cavity and the w2 light output from the second FP cavity, respectively, and perform negative feedback adjustment control on the first femtosecond optical comb and the second femtosecond optical comb according to the photoelectric conversion information.

[0062] The negative feedback regulation control in step S5 specifically includes the following steps:

[0063] S501. The w1 light output from the first FP cavity (FP cavity 1) is input to the first photodetector PD1, converted into a first electrical signal, and the first femtosecond optical comb is controlled according to the feedback of the first electrical signal.

[0064] S502. The w2 light output from the second FP cavity (FP cavity 2) is input to the second photodetector PD2, converted into a second electrical signal, and the second femtosecond optical comb is controlled based on the feedback of the second electrical signal.

[0065] The feedback control includes the following steps:

[0066] S503. Determine whether the voltage measured by the first photodetector PD1 / second photodetector PD2 is lower than the set voltage value. If it is lower, increase the PZT driving voltage in the first FP cavity (FP cavity 1) / second FP cavity (FP cavity 2) to lengthen the femtosecond optical comb resonant cavity and increase the repetition frequency. f r Get smaller;

[0067] S504. Next, determine whether the voltage measured by the first photodetector PD1 / second photodetector PD2 has increased. If it has, continue to increase the PZT driving voltage to lengthen the femtosecond optical comb resonant cavity and increase the repetition frequency. f r The voltage is reduced until the voltage measured by the first photodetector PD1 / second photodetector PD2 is not lower than the set voltage value; if it decreases further, the PZT driving voltage is reduced to shorten the cavity length and increase the repetition frequency. f rThe voltage is increased until the voltage measured by the first photodetector PD1 / second photodetector PD2 is not lower than the set voltage value. When the femtosecond light and the modulated light in the FP cavity resonate and enhance transmission, the voltage value detected by PD1 at this time is taken as the set voltage value. In this embodiment, as... Figure 1 As shown, the first femtosecond optical comb ( Figure 1 The second femtosecond optical comb (abbreviated as femtosecond optical comb 1) and the second femtosecond optical comb (abbreviated as femtosecond optical comb 2) Figure 1 The femtosecond optical comb (hereinafter referred to as femtosecond optical comb 2) adopts the same negative feedback control. The object of negative feedback control is the PZT driving voltage in the first FP cavity (FP cavity 1) / the second FP cavity (FP cavity 2). The piezoelectric ceramic has the function of changing the cavity length when the voltage changes, thereby realizing feedback control of the repetition frequency of the first femtosecond optical comb and the second femtosecond optical comb.

[0068] S6. Input the adaptive sampling clock signal as the clock signal into the data acquisition card DAP, and input the current signal generated by PCA2 in the previous step as the signal to be acquired into the data acquisition card DAP to realize the asynchronous sampling acquisition of the THz time domain signal with adaptive compensation. After Fourier spectrum transformation, high-precision THz spectrum detection is achieved.

[0069] A terahertz dual-comb spectrometer stabilization control system, constructed using the aforementioned method, includes two femtosecond optical combs 1 and 2 with different repetition frequencies, several photodetector modules (photodetector PD-1, first photodetector PD1, second photodetector PD2, third photodetector PD3, and fourth photodetector PD4), a continuous laser, two electro-optic modulators (EOM1 and EOM2), two optical comb cavities (first femtosecond optical comb EP cavity 1 and second femtosecond optical comb EP cavity 2), a first photoconductive antenna PCA1 and a second photoconductive antenna PCA2, a feedback control module, an adaptive clock extraction module, and a data acquisition card. The feedback control module includes photodetectors (first photodetector PD1 and second photodetector PD2), a voltage amplifier, and a feedback control circuit. The adaptive clock extraction module includes a beam combiner, photodetectors (photodetector PD-1, third photodetector PD3, and fourth photodetector PD4), and mixers (first mixer M1 and second mixer M2). The transmitted light at frequencies w1 and w2 is processed by beat frequency, mixing, and sum frequency to extract the signal containing the jitter of the repetition frequency of the two femtosecond optical combs as an adaptive sampling clock. The data acquisition card's input information includes the adaptive sampling clock signal, a trigger signal, and a THz current signal converted to radio frequency. Detailed implementation method:

[0071] like Figure 1As shown, the solid arrows indicate the direction of optical pulse transmission, and the dashed arrows indicate the direction of electrical signal transmission. Two femtosecond optical combs with slightly different repetition frequencies are used as laser sources, namely femtosecond optical comb 1 (repetition frequency of...). f r1 ), femtosecond optical comb 2 (repetition frequency is f r2 , f r2 = f r1 +∆ f r ), ∆ f r The repetition frequency difference between the two femtosecond optical combs is used to adjust the cavity length of the first FP cavity (FP cavity 1) / the second FP cavity (FP cavity 2) to ensure long-term system stability. Femtosecond optical comb 1 outputs a high-energy femtosecond beam and two low-energy femtosecond beams. The high-energy beam acts on the first photoconductive antenna PCA1, generating a THz optical comb. Femtosecond optical comb 2 outputs a high-energy femtosecond beam and two low-energy femtosecond beams. The high-energy beam acts on the second photoconductive antenna PCA2 for detection, exciting carriers with the same repetition frequency as femtosecond optical comb 2. Due to the slight difference in the repetition frequencies of the two femtosecond optical combs, the THz optical comb generated by the first photoconductive antenna PCA1 and the carriers of the detection antenna undergo an asynchronous sampling process. A weak current signal reflecting the THz electric field is obtained on the second photoconductive antenna PCA2. This current signal contains the repetition frequency jitter of the two femtosecond optical combs.

[0072] This feedback control process sets the repetition frequency of the first femtosecond optical comb 1. f r1 The locking is traced back to the higher-order mode of the first modulated light. Similarly, the repetition frequency of the second femtosecond optical comb 2 is determined by, as... Figure 2 The feedback process shown locks the modulation light into a higher-order mode. Since the first and second modulation lights originate from electro-optic modulation, they not only have high modulation frequencies but are also less affected by the external environment, resulting in higher stability. Based on the frequency-selective feedback control process of FP cavity 1 and FP cavity 2, long-term stable control of the two femtosecond optical comb light sources can be achieved, providing a guarantee for THz dual-comb spectroscopy.

[0073] The adaptive clock signal n ∆ obtained by mixing by mixer M2 f r The clock signal is input to the data acquisition card DAP, and the current signal generated by PCA2 is input to the data acquisition card DAP as the signal to be acquired, so as to realize the asynchronous sampling acquisition of THz time domain signal adaptive compensation, and realize high-precision THz spectrum detection through Fourier spectrum transformation.

[0074] The above descriptions are merely embodiments of the present invention. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, based on the guidance provided in this application, improve and implement this solution in combination with their own capabilities. Some typical well-known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for stabilizing and controlling a terahertz dual-comb spectrometer, characterized in that, Includes the following steps: S1. Use two femtosecond optical combs with a difference in repetition frequency as laser sources; S2. Couple the low-energy femtosecond light output from the first femtosecond optical comb into the first FP cavity, and couple the low-energy femtosecond light output from the second femtosecond optical comb into the second FP cavity. The light output from the continuous laser is input into the first electro-optic modulator and the second electro-optic modulator respectively to obtain the first modulated light and the second modulated light respectively, and the first modulated light and the second modulated light are coupled into the first FP cavity and the second FP cavity respectively. The light output from the continuous laser is input into the third and fourth photodetectors, respectively. The low-energy femtosecond light output from the first femtosecond optical comb is input into the third photodetector to obtain the second beat frequency signal; the low-energy femtosecond light output from the second femtosecond optical comb is input into the fourth photodetector to obtain the third beat frequency signal; the second beat frequency signal and the third beat frequency signal are mixed by the first mixer to obtain the first mixed electrical signal. S3, output from the first FP cavity Optical output from the second FP cavity Optical coupling is performed to a photodetector (PD-1) to acquire the first beat frequency signal; S4. Extract frequency jitter information containing the first femtosecond optical comb and the second femtosecond optical comb based on the first beat frequency signal, perform data processing based on the frequency jitter information, mix the first beat frequency signal and the first mixing electrical signal through the second mixer to obtain the second mixing electrical signal, and use the second mixing electrical signal as the adaptive sampling clock signal for the data acquisition card to acquire THz data of the first femtosecond optical comb and the second femtosecond optical comb. S5. Obtain the output of the first FP cavity respectively. Optical output from the second FP cavity The photoelectric conversion information of light is obtained, and the first femtosecond optical comb and the second femtosecond optical comb are adjusted and controlled by negative feedback according to the photoelectric conversion information.

2. The stabilization control method for a terahertz dual-comb spectrometer according to claim 1, characterized in that: The negative feedback regulation control in step S5 specifically includes the following steps: S501, outputting the first FP cavity Light is input to the first photodetector, converted into a first electrical signal, and the first femtosecond optical comb is controlled based on the feedback of the first electrical signal. S502, outputting the second FP cavity The light is input to the second photodetector, converted into a second electrical signal, and the second femtosecond optical comb is controlled based on the feedback of the second electrical signal.

3. The stabilization control method for a terahertz dual-comb spectrometer according to claim 2, characterized in that: The feedback control includes the following steps: S503. Determine whether the voltage measured by the first photodetector / second photodetector is lower than the set voltage value. If it is lower, increase the PZT driving voltage in the first FP cavity / second FP cavity to lengthen the femtosecond optical comb resonant cavity and increase the repetition frequency. Get smaller; S504. Next, determine whether the voltage measured by the first photodetector / second photodetector has increased. If it has increased, continue to increase the PZT driving voltage to lengthen the femtosecond optical comb resonant cavity and increase the repetition frequency. The voltage is reduced until the voltage measured by the first photodetector / second photodetector is not lower than the set voltage value; if it decreases further, the PZT driving voltage is reduced to shorten the cavity length and increase the repetition frequency. Increase until the voltage measured by the first photodetector / second photodetector is not lower than the set voltage value.

4. The stabilization control method for a terahertz dual-comb spectrometer according to claim 1, characterized in that: Step S2 further includes the following steps: S201. Input the high-energy femtosecond light output from the first femtosecond optical comb into the first photoconductive antenna, and input the high-energy femtosecond light output from the second femtosecond optical comb into the second photoconductive antenna. S202. The THz optical comb generated by the first photoconductive antenna is transmitted to the second photoconductive antenna to obtain a current signal reflecting the THz electric field, and the current signal is input to the data acquisition card.

5. The stabilization control method for a terahertz dual-comb spectrometer according to claim 1, characterized in that: The first and second femtosecond optical combs are two femtosecond laser sources with a fixed difference in repetition frequency and a pulse width on the order of hundreds of fs. Their repetition frequency and carrier envelope phase are respectively... , and , , , This represents the difference in repetition frequency between the two femtosecond optical combs.

6. The stabilization control method for a terahertz dual-comb spectrometer according to claim 5, characterized in that: The length of the first FP cavity is The length of the second FP cavity is Both the first and second FP cavities comprise two parallel plates with high reflectivity disposed on piezoelectric ceramics; the first modulated light is coupled into the first FP cavity at a zero-degree incident angle, and its cavity length satisfies The second modulated light is coupled into the second FP cavity at a zero-degree incident angle, and its cavity length satisfies ,in k It is an integer. c At the speed of light, n The refractive index of air is 100m, which represents the 100mth tooth of the first and second femtosecond optical combs mentioned above.

7. The stabilization control method for a terahertz dual-comb spectrometer according to claim 6, characterized in that: The Light and The light source consists of two narrow linewidth beams; ， ； in, The modulation frequency of the first electro-optic modulator. This is the modulation frequency of the second electro-optic modulator.

8. A stabilization control system for a terahertz dual-comb spectrometer, characterized in that: Its construction utilizes the method described in any one of claims 1-7, including two femtosecond optical combs with different repetition frequencies, a number of photoelectric detection modules, a continuous laser, two electro-optic modulators, two FP cavities, a first photoconductive antenna and a second photoconductive antenna, a feedback control module, an adaptive clock extraction module, and a data acquisition card.

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