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
US6381019B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 30, 2000 |
| Grant date | Apr 30, 2002 |
| Priority date | — |
| Expiry date | Jun 30, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/0423
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
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 constan…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.