Terahertz frequency domain spectrometer with frequency shifting of source laser beam
First Claim
1. An apparatus for analyzing, identifying or imaging a target, comprising:
- a first housing including first and second lasers having tunable frequencies and coupled to first and second optical fibers respectively, 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, wherein a first portion of said first output beam and a first portion of said second output beam are to produce a first composite output beam configured to be swept over a frequency band as the frequencies of at least one of the lasers is swept, wherein the first housing further comprises;
a frequency shifting element coupled to a reference oscillator and positioned to receive a second portion of said first output beam to controllably shift the frequency of said second portion of said first output beam; and
a beam combiner coupled to the output of the frequency shifting element and to a second portion of the second output beam to produce a second composite output beam;
a second housing including (i) a first photoconductive switch activated by the second composite output beam for producing electromagnetic radiation in a range of frequencies greater than 100 GHz, and (ii) a radiator for directing said radiation to a target; and
a third housing including (i) a receiver for acquiring electromagnetic radiation in a range of frequencies greater than 100 GHz from the target, and (ii) a second photoconductive switch activated by the first composite output beam and coupled to the electromagnetic radiation from the receiver and functioning to generate an electrical signal representative of some characteristic of the target.
4 Assignments
0 Petitions
Accused Products
Abstract
An apparatus for analyzing, identifying or imaging an target including first and second laser beams coupled to a pair of photoconductive switches to produce CW signals in one or more bands in a range of frequencies greater than 100 GHz focused on and transmitted through or reflected from the target; and a detector for acquiring spectral information from signals received from the target and using a multi-spectral heterodyne process to generate an electrical signal representative of some characteristics of the target. The lasers are tuned to different frequencies and a frequency shifter in the path of one laser beam allows the terahertz beam to be finely adjusted in one or more selected frequency bands.
-
Citations
19 Claims
-
1. An apparatus for analyzing, identifying or imaging a target, comprising:
-
a first housing including first and second lasers having tunable frequencies and coupled to first and second optical fibers respectively, 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, wherein a first portion of said first output beam and a first portion of said second output beam are to produce a first composite output beam configured to be swept over a frequency band as the frequencies of at least one of the lasers is swept, wherein the first housing further comprises; a frequency shifting element coupled to a reference oscillator and positioned to receive a second portion of said first output beam to controllably shift the frequency of said second portion of said first output beam; and a beam combiner coupled to the output of the frequency shifting element and to a second portion of the second output beam to produce a second composite output beam; a second housing including (i) a first photoconductive switch activated by the second composite output beam for producing electromagnetic radiation in a range of frequencies greater than 100 GHz, and (ii) a radiator for directing said radiation to a target; and a third housing including (i) a receiver for acquiring electromagnetic radiation in a range of frequencies greater than 100 GHz from the target, and (ii) a second photoconductive switch activated by the first composite output beam and coupled to the electromagnetic radiation from the receiver and functioning to generate an electrical signal representative of some characteristic of the target. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
-
Specification