Ultrasonic generator and detector using an optical mask having a grating for launching a plurality of spatially distributed, time varying strain pulses in a sample [electronic resource].

Published:: Providence, R.I. : Brown University, 2002.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Additional Creators:: Brown University and United States. Department of Energy. Office of Scientific and Technical Information

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Summary:

A method and a system are disclosed for determining at least one characteristic of a sample that contains a substrate and at least one film disposed on or over a surface of the substrate. The method includes a first step of placing a mask over a free surface of the at least one film, where the mask has a top surface and a bottom surface that is placed adjacent to the free surface of the film. The bottom surface of the mask has formed therein or thereon a plurality of features for forming at least one grating. A next step directs optical pump pulses through the mask to the free surface of the film, where individual ones of the pump pulses are followed by at least one optical probe pulse. The pump pulses are spatially distributed by the grating for launching a plurality of spatially distributed, time varying strain pulses within the film, which cause a detectable change in optical constants of the film. A next step detects a reflected or a transmitted portion of the probe pulses, which are also spatially distributed by the grating. A next step measures a change in at least one characteristic of at least one of reflected or transmitted probe pulses due to the change in optical constants, and a further step determines the at least one characteristic of the sample from the measured change in the at least one characteristic of the probe pulses. An optical mask is also disclosed herein, and forms a part of these teachings.

Report Numbers:

E 1.99:us 6381019
us 6381019

Other Subject(s):

Ultrasonic Generator Detector Optical Mask Grating Launching Plurality Spatially Distributed Time Varying Strain Pulses Sample Method Disclosed Determining Characteristic Sample Contains Substrate Film Disposed Surface Substrate Method Step Placing Mask Free Surface Film Mask Top Surface Bottom Surface Placed Adjacent Free Surface Film Bottom Surface Mask Formed Plurality Features Forming Grating Step Directs Optical Pump Pulses Mask Free Surface Film Individual Ones Pump Pulses Followed Optical Probe Pulse Pump Pulses Spatially Distributed Grating Launching Plurality Spatially Distributed Time Varying Strain Pulses Film Detectable Change Optical Constants Film Step Detects Reflected Transmitted Portion Probe Pulses Spatially Distributed Grating Step Measures Change Characteristic Reflected Transmitted Probe Pulses Due Change Optical Constants Step Determines Characteristic Sample Measured Change Characteristic Probe Pulses Optical Mask Disclosed Forms Teachings Pump Pulse Pump Pulse Pump Pulse

Note:

Published through SciTech Connect.
01/01/2002.
"us 6381019"
Maris, Humphrey J.

Funding Information:

FG02-86ER45267

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