Terahertz time-domain spectroscopy system and step length adaptive adjustment method thereof

Abstract

The invention discloses a terahertz time-domain spectroscopy system step length adaptive adjustment method which comprises the following steps: (1) starting from an initial delay value ds, controlling an optical fiber delay line to start scanning according to a fixed step length; and (2) identifying the obtained terahertz spectrum time domain waveform, judging (or predicting) whether the terahertz spectrum time domain waveform belongs to a characteristic peak value data region, if so, setting the step length of the next step as a smaller step length, otherwise, setting the step length of the next step as a larger step length. The self-adaptive variable step length method is adopted, so that the scanning time is obviously shortened while the feature data acquisition precision is ensured, and the detection efficiency is improved. Meanwhile, the invention discloses a terahertz time-domain spectroscopy system based on a task computer, the dependence on an external computer in the spectral measurement process is relieved, the requirement for the computing performance of the computer is reduced, and the expandability of the system is enhanced.

Description

Technical field: [0001] The invention belongs to the technical field of terahertz spectroscopy and imaging, and in particular relates to a method for adaptively adjusting the step size of a terahertz time-domain spectroscopy system. Background technique: [0002] Such as figure 1 As shown, the terahertz time-domain spectroscopy system includes a femtosecond laser 1, a fiber delay line 2, a photoconductive transmitting antenna 3, a bias source 4, a photoconductive receiving antenna 5, a lock-in amplifier 6, and a computer (host computer) 7. First, Femtosecond laser 1 generates femtosecond laser 1 into sub-beams, one beam is pump light, and the other beam is probe light. Under the action of bias voltage source 4, the pump light is irradiated on THz photoconductive transmitting antenna 3 to form Photogenerated free carriers, when the terahertz pulse and the probe light irradiate the electrode gap of the THz photoconductive receiving antenna 5 at the same time, the femtosecond ...

AI Technical Summary

Problems solved by technology

The characteristic peak width of common substances is only less than 1 ps. If the step size is forcibly increased, the number of acquisition points and time consumption will be reduced, but the amount of scanning data for the characteristic peak part is too small to accurately present its time-domain spectral characteristics.

The whole system relies heavily on the external computer 7, and cannot even work without an external computer for process control. At the same time, because of the need for more complex calculations, it also has certain requirements for the computing power of the external computer.

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