Method for continuously regulating central frequency and spectrum width of THz (terahertz) wave

Abstract

The invention relates to a method for continuously regulating central frequency and spectrum width of THz (terahertz) wave. A bundle of ultrafast laser pulse passes through a movable birefringence crystal oblique split pair and a zero-order quarter wave plate to generate a novel specially-polarized light field by a polarizing gate method. The novel light field passes through a polarizer to obtain laser pulse with width of narrow pulse with linear polarization. Laser pulses different in width are obtained by controlling inserting quantity of the birefringence crystal oblique split pair, and accordingly the function of regulating central frequency and spectrum width of the THz wave is achieved. A device is simple and easy to operate, the width of the novel laser pulse can be changed only two crystals of the birefringence crystal oblique split pair simultaneously move oppositely at equal distance, and accordingly the central frequency and the spectrum width are adjusted. The method is suitable for light sources of various pulse widths and wavelengths.

Description

technical field [0001] The invention relates to an electromagnetic wave adjustment technology, in particular to a method for continuously adjusting the center frequency and spectrum width of a terahertz wave. Background technique [0002] In recent decades, terahertz waves have become an important research topic in the field of physics internationally due to their wide application prospects. Terahertz radiation is an electromagnetic wave with a frequency in the range of 0.1 to 10 THz. This band is located between microwave and infrared. It has the characteristics of rich information, high space-time coherence, and low photon energy. The field of science has enormous application value. At present, the main applied researches are terahertz time-domain spectroscopy, terahertz imaging technology, security inspection, terahertz radar, astronomy, and communication technology. [0003] At present, the generation of broadband terahertz pulses mainly includes three methods: photoco...

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Problems solved by technology

[0009] The present invention is aimed at the problem that most current terahertz pulse generation techniques can only generate terahertz waves with a single center frequency and a certain spectrum width, and it is difficult to adjust the frequency and spectrum width, and proposes a method for continuously adjusting the center frequency and spectrum width of terahertz waves. The method uses the polarization gate method to generate a new optical field with special polarization by passing a beam of ultrafast laser pulses through a movable birefringent crystal wedge pair and a zero-order 1 / 4 wave plate.

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