Patent ID: 9029775
Filing Date: 2015-05-12
Classification: G01J,G01N

Abstract:
1. A terahertz spectrometer comprising: first and second lasers having tunable frequencies, said first laser to produce a first output beam and said second laser to produce a second output beam, said first output beam and said second output beam having different frequencies; a phase modulator positioned to receive a first portion of said first output beam to controllably modulate the phase of the first output beam and producing a modulated third output beam; a signal source coupled to the phase modulator to allow the first output beam to be swept in phase over 360 degrees; a first optical element coupled to the modulated third output beam and to a portion of the second output beam to produce a composite output beam; a source including a first photoconductive switch activated by the composite fourth output beam to produce CW signals in a range of frequencies from 100 GHz to over 2 THz in dependence on a frequency difference between the first and second output beams; a radiative element coupled to the source of CW signals for causing the CW signals to be substantially simultaneously focused on or through the target; a second optical element coupled to a portion of the first output beam and to a portion of the second output beam to produce a composite fifth output beam; a detector for acquiring spectral information from said target and coupled to the composite fifth output beam, and generating, based on said spectral information and the composite fifth output beam, an electrical signal representative of a characteristic of the target, wherein the signal source is operable to control the phase of the CW signals for removal of an interference pattern, resulting from constructive or destructive interference between the CW signals and the composite fifth output beam on the detector as the frequency of the CW signals is swept, in the electrical signal.