Method for increasing time-resolved terahertz spectrum signal-to-noise ratio through double-phase-locking technique

Abstract

The invention relates to a method for increasing the time-resolved terahertz spectrum signal-to-noise ratio through a double-phase-locking technique. The method comprises the steps: firstly a time-resolved terahertz spectrum system is set up; secondarily, a delay line needs to be scanned to complete signal input of a detection part; then signals of the detection part are input into two phase-locking amplifiers, and meanwhile signal synchronization between two choppers and the two phase-locking amplifiers is completed; and then signal synchronization of the chopper in a terahertz generation part to the chopper in a pump part is achieved, then the signals where pump optical path background noise is filtered out are input into phase-locking amplifiers in the generation part from the phase-locking amplifiers to subtract signals where background noise of the generation part is filtered out, the signal difference value delta E/E is finally obtained through demodulation of the phase-locking amplifiers in the generation part, and the sample complete carrier dynamic process can be obtained by scanning the delay line. The signal-to-noise ratio of the system can be increased greatly, and themethod can be used for the time-detected terahertz system and is also applicable to small-signal strong-background noise occasions.

Description

technical field [0001] The invention belongs to the technical field of improving the signal-to-noise ratio of time-resolved terahertz spectroscopy in ultrafast spectroscopy technology, and specifically relates to a method for improving the signal-to-noise ratio of time-resolved terahertz spectroscopy by using a double phase-locking technology. Background technique [0002] Terahertz spectroscopy technology is an effective means of conducting spectral research in the terahertz band, and can study the characteristics 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 light-induced changes in the sample signal. The in-band charge transfer process was studied. Compared with teraher...

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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