Dual wavelength holographic interferometry system and method

US4810094A · kind A · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventors

• William K. Witherow · Huntsville, US
• Andreas Ecker · Ratingen, DE

Key dates

• Filing date: Jan 29, 1988
• Grant date: Mar 7, 1989
• Expiry date: Jan 29, 2008

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N21/453
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The present invention relates to a two-wave holographic interferometry system and method. In such systems, a reference beam holographic is super-imposed on an object beam, the object beam being an image obtained by passing a beam through an object regarding which some parameter (e.g. temperature gradient) is to be measured. A photograph (50) of the superimposed beams (D) is taken. The present invention employs two object (B) and two reference (A) beams and the invention is particularly concerned with the use of a prism assembly (C) which causes the two different wavelengths (W1, W2) of the object beams to emerge from the prism at slightly different angles, thereby providing two holographic images which are slightly displaced from each other.