Optical evaluation method by means of laser pulses and corresponding apparatus

US8253937B2 · kind B2 · utility

Assignee

• LEICA MICROSYSTEMS CMS GMBH · DE

Inventors

• Vishnu Vardhan Krishnamachari · Seeheim-Jugenheim, DE
• William C. Hay · Heppenheim, DE
• Volker Seyfried · Schallstadt, DE
• Bernd Widzgowski · Dossenheim, DE

Key dates

• Filing date: Nov 25, 2009
• Grant date: Aug 28, 2012
• Expiry date: May 6, 2030

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N21/63
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An optical evaluation method and an apparatus for performing said method are described. First laser pulses of a first type and second laser pulses of a second type that differs from the first type are sent onto a sample to be examined. The sample is hit with first incident light from the two laser pulses in at least one manner of simultaneously, within a very short time lag between the two laser pulses, and a time-correlated manner of the two laser pulses, thereby generating a first optical signal, and hit with second incident light from the two laser pulses, thereby generating a second optical signal. The generated first and second optical signals are detected with at least one detector; and an electronic difference between the first and second optical signals is generated.