Polarization interferometer as a proximity sensor

✍ Scribed by H.Y. Stoyanov

• Book ID: 104159479
• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 230 KB
• Volume: 32
• Category: Article
• ISSN: 0030-3992
• DOI: 10.1016/s0030-3992(00)00036-0

✦ Synopsis

A simple interferometric phasemeter which can be used as a proximity sensor is described. It is based on the measurement of the phase shift between the p-and s-components of a ®eld caused by the processes of attenuation in total internal re¯ection. The role of the interferometer is to restore the p-and the s-components from the resultant totally re¯ected ®eld, with minimum amplitude and phase distortions and to let them interfere. The phase shift as a function of the attenuation of the total internal re¯ection can be determined from the interference signal. The interferometer is of a common path polarization shearing type, consisting of Rochon beamsplitter and a linear polarizer. An experiment for measuring the distance between glass plane surface and a plane attenuater made of Si mono-crystal is described. A good agreement between theory and experiment for separations less than 300 nm is observed. This device can be applied in research and metrology. After further modi®cations, the optical system could be used for proximity sensing, surface geometry control, variable optical retarders, contamination monitoring, etc.