High signal-to-noise ratio terahertz device based on optical ruler sensing and signal sampling method

Abstract

The invention discloses a high signal-to-noise ratio terahertz device based on optical ruler sensing and a signal sampling method. In the high signal-to-noise ratio terahertz device, an optical fiberfemtosecond laser is connected with a THz emitter through a THz emitter tail fiber, and is connected with a delay line inlet optical fiber flange coupler through an optical fiber jumper; a delay lineoutlet optical fiber flange coupler is connected with a THz receiver through a THz receiver tail fiber; a high-speed data acquisition card is respectively connected with an optical ruler controller, acontrol computer and the THz receiver through data lead wires; the optical ruler controller is a controller for performing sensing control and position display on an optical ruler; and the high-speeddata acquisition card adopts a high-speed multi-path synchronous acquisition data card and is used for acquiring output signals of the THz receiver and acquiring output signals of the optical ruler controller at the same time. The high signal-to-noise ratio terahertz device has the advantages of rapidness, effectiveness, high flexibility, low technical implementation difficulty, excellent workingperformance and the like, and the performance index of the THz spectrometer can be greatly improved.

Description

technical field [0001] The invention relates to the technical field of terahertz instruments, in particular to a terahertz device with high signal-to-noise ratio and a signal sampling method based on optical ruler sensing. Background technique [0002] Traditional terahertz (THz) spectrometers are constrained by limiting factors, and their optimal sampling scan rate is very low. It usually takes more than ten or even tens of minutes to complete the sampling of one THz pulse period, which seriously affects the efficiency and timeliness of the test. Limit its application prospects in some fields. The traditional technology is mainly affected by two aspects of technology, resulting in its low efficiency: the first aspect is the restriction of the mechanical structure, THz time-domain spectrometers are all based on the staggered sampling technology to perform the time-domain equivalent reproduction of THz pulses, To complete the wrong-step sampling, it is necessary to separate ...

AI Technical Summary

Problems solved by technology

[0002] Traditional terahertz (THz) spectrometers are constrained by limiting factors, and their optimal sampling scan rate is very low. It usually takes more than ten or even tens of minutes to complete the sampling of one THz pulse period, which seriously affects the efficiency and timeliness of the test. Limit its application prospects in some fields

The traditional technology is mainly affected by two aspects of technology, resulting in its low efficiency: the first aspect is the restriction of the mechanical structure, THz time-domain spectrometers are all based on the staggered sampling technology to perform the time-domain equivalent reproduction of THz pulses, To complete the wrong-step sampling, it is necessary to separate the two laser pulses of pumping and detection. Traditional instruments use mechanical stepping motors or DC translation stages to complete this work, because the motor must decelerate and accelerate every step. process, causing the waiting interval between sampling points to be too long, thereby prolonging the overall sampling time; the second aspect is the restriction of the integration time of the lock-in amplifier. Since the signal-to-noise ratio of the THz signal is not high, traditional technology uses Lock-in amplification technology to improve the dynamic range of the signal, although good results have been achieved, but due to too many sampling points, the cumulative integration time is too long, which affects the data output efficiency of the lock-in amplifier, and also reduces to a certain extent system efficiency

[0003] In recent years, multi-phase stepper motor phase signals have also been used as sensor feedback sampling signals in existing technical solutions. Although the sampling speed has been increased, due to the structural problems of the stepper motor itself, there are often overspeed, overtorque and Out-of-synchronization occurs, which seriously affects the accuracy of signal sampling corresponding to the time axis

Although the encoder can receive the signal and make some adjustments, the control mechanism is too complicated, and the error cannot be completely eliminated, and the accumulation will gradually increase over time. Therefore, how to implement low-cost and highly operable fast THz Time-domain signal detection has always been a key technology, and this bottleneck has seriously hindered the market promotion process of this instrument

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