Intra-Cavity Total Reflection For High Sensitivity Measurement Of Optical Properties

Patent · Tue Aug 24 04:00:00 EDT 1999

OSTI ID:879724

Pipino, Andrew C. R. ^[1]; Hudgens, Jeffrey W ^[2]

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1. Gaithersburg, MD
2. Rockville, MD

An optical cavity resonator device is provided for conducting sensitive murement of optical absorption by matter in any state with diffraction-limited spatial resolution through utilization of total internal reflection within a high-Q (high quality, low loss) optical cavity. Intracavity total reflection generates an evanescent wave that decays exponentially in space at a point external to the cavity, thereby providing a localized region where absorbing materials can be sensitively probed through alteration of the Q-factor of the otherwise isolated cavity. When a laser pulse is injected into the cavity and passes through the evanescent state, an amplitude loss resulting from absorption is incurred that reduces the lifetime of the pulse in the cavity. By monitoring the decay of the injected pulse, the absorption coefficient of manner within the evanescent wave region is accurately obtained from the decay time measurement.

• Research Organization: DEPARTMENT OF COMMERCE
• DOE Contract Number: AI07-97ER62518
• Assignee: The United States of America as represented by the Secretary of Commerce (Washington, DC)
• Patent Number(s): US 5943136
• Application Number: 09/962170
• OSTI ID: 879724
• Country of Publication: United States
• Language: English