Method of performing optical measurement on a sample
US7369234B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 24, 2004 |
| Grant date | May 6, 2008 |
| Priority date | — |
| Expiry date | Jul 23, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/211
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention relates to a method of performing an optical measurement on a sample, such as an ellipticity measurement. The sample is irradiated with a polarized irradiation beam and a return beam is linearly polarized. The irradiation or return beam is modulated with a birefringence modulator, such as a photoelastic modulator, in accordance with a primary modulation signal. The return beam is directed onto a multichannel detector. Typically the detector is a slow detector, such as a CCD, having a response time greater than a period of the primary modulation signal. Detection values are generated simultaneously at each detection element and processed to determine a plurality of measurements. Various measurement techniques are described, including detector signal averaging over gated intervals; a design employing coherent modulation of the gain of an ICCD , and a modulator-coherent flash lamp design.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.