Stephen E Maxwell

US Patent:

8642982, Feb 4, 2014

Filed:

Mar 14, 2013

Appl. No.:

13/827476

Inventors:

Kevin O. Douglass - Columbia MD, US
Stephen E. Maxwell - Gaithersburg MD, US
Joseph T. Hodges - Washington Grove MD, US
David A. Long - Bethesda MD, US
Gar-Wing Truong - Crawley, AU

Assignee:

The United States of America, as represented by the Secretary of Commerce, NIST - Washington DC

International Classification:

G01J 3/45
G01J 3/10
G01J 1/08
G01B 9/02

US Classification:

2504931, 250351, 359332, 35933722, 359237, 356332, 356 731

Abstract:

A fast switching arbitrary frequency light source for broadband spectroscopic applications. The light source may operate near 1. 6 um based on sideband tuning using an electro-optic modulator driven by an arbitrary waveform generator. A Fabry-Perot filter cavity selects a single sideband of the light source. The finesse (FSR/Δν) of the filter cavity may be chosen to enable rapid frequency switching at rates up to 5 MHz over a frequency range of 40 GHz (1. 3 cm). The bandwidth, speed and spectral purity are high enough for spectroscopic applications where rapid and discrete frequency scans are needed. Significant signal-to-noise advantages may be realized using the rapid and broadband scanning features of this system in many areas of spectroscopy, e. g. , process monitoring and control, reaction dynamics, and remote sensing (e. g. , greenhouse gas monitoring, biological/chemical agent screening).