Spectral-domain interferometric method and system for characterizing terahertz radiation

摘要

A method and system based on spectral domain interferometry for detecting intense THz electric field, allowing the use of thick crystal for spectroscopic purposes, in order to makes long temporal scans for increased spectral resolutions, and overcoming the limitation of over-rotation for presently available high power THz sources. Using this method and system the phase difference of approximately 8898π can be measured, which is 18000 times higher than the phase difference measured by electro-optic sampling (π/2).

主权项

1. A spectral domain interferometry system for characterizing terahertz radiation, comprising:
a terahertz source, generating a terahertz pulse from a pump beam; a glass plate generating, from a probe beam, two pulses separated by an optical delay longer than the duration of the THz pulse; an off-axis mirror; a first and a second cylindrical lenses; a detector crystal; and a spectrometer; wherein the terahertz pulse is focused into the detector crystal by said off-axis mirror, said two pulses propagate through the first cylindrical lens and a hole in said off-axis mirror, are line focused onto the detector crystal at the same position as the terahertz pulse and propagate through said second cylindrical lens to said spectrometer, said spectrometer measuring changes in interference between the two pulses generated by said glass plate due to birefringence induced by the terahertz electric field.