A method for improving the signal-to-noise ratio of time-resolved terahertz spectroscopy using double phase-locking technology

Abstract

The invention relates to a method for improving the signal-to-noise ratio of a time-resolved terahertz spectrum by using double phase locking technology. First, a time-resolved terahertz spectrum system is built; secondly, a delay line needs to be scanned to complete the signal input of the detection part; then the signal input of the detection part is required In the two lock-in amplifiers, the signal synchronization between the two choppers and the two lock-in amplifiers is completed at the same time; then the signal synchronization between the chopper in the terahertz generation part and the chopper in the pump part is realized, and then the The signal that filters out the background noise of the pump optical path is obtained from the lock-in amplifier in the input generation part of the lock-in amplifier, and makes a difference with the signal that filters out part of the background noise. After demodulation of the generated part of the lock-in amplifier, the signal difference ΔE / E is finally obtained, Scan the delay line to get the complete carrier dynamics process of the sample. The invention can greatly improve the signal-to-noise ratio of the system, and can not only be used in the time detection terahertz system, but also in the occasion of small signal and strong background noise.

Description

technical field [0001] The invention belongs to the technical field of signal-to-noise ratio improvement of time-resolved terahertz spectrum in ultrafast spectroscopy technology, and particularly relates to a method for improving the signal-to-noise ratio of time-resolved terahertz spectrum by using double phase locking technology. Background technique [0002] Terahertz spectroscopy technology is an effective means of spectral research in the terahertz band, which can study the properties of substances in various fields such as biology, environment, medicine, security inspection and communication. Time-resolved terahertz spectroscopy, as an effective non-contact detection method developed in recent years by combining terahertz time-domain spectroscopy and pump-detection technology, can directly observe the information reflected by the photo-induced changes of the sample signal. Intraband charge transfer process was investigated. Compared with terahertz time-domain spectros...

AI Technical Summary

Problems solved by technology

However, the current signal acquisition method used in the time-resolved terahertz system is generally only applied to a lock-in amplifier, and the signal-to-noise ratio is not high enough, resulting in the annihilation of effective information noise and the inability to accurately obtain material properties and ultrafast dynamics information.

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