Sinusoidal wavelength-scanning interferometers using a superluminescent diode

Osami Sasaki; Norihiko Murata; Kazuhiro Akiyama; Takamasa Suzuki

doi:10.1117/12.357778

17 August 1999 Sinusoidal wavelength-scanning interferometers using a superluminescent diode

Osami Sasaki, Norihiko Murata, Kazuhiro Akiyama, Takamasa Suzuki

Proceedings Volume 3745, Interferometry '99: Applications; (1999) https://doi.org/10.1117/12.357778
Event: International Conference on Optical Metrology, 1999, Pultusk Castle, Poland

Abstract

Two different sinusoidal wavelength-scanning (SWS) interferometers with a SWS light source using a superluminescent laser diode are proposed for step-profile measurement and real-time distance measurement, respectively. An optical path difference (OPD) longer than a wavelength is measured from detection of sinusoidal phase- modulation amplitude Z_b of the interference signal that is proportional to the OPD and the scanning width 2b. In step-profile measurement, if measurement error in the OPD obtained from Z_b is smaller than a half wavelength, this measured value of the OPD is combined with a fractional value of the OPD obtained from the conventional phase of the interference signal. This combination enables us to measure the OPD longer than a wavelength with a high accuracy of a few nm. In real-time distance measurement, the amplitude Z_b is kept at a specified constant value for changes of OPD by controlling the scanning width 2b of the wavelength with a feedback system. The amplitude Z_b is detected by processing the interference signal with electric circuits in real-time. The value of b is easily controlled in the SWS light source, and an OPD longer than a wavelength is measured from the value of b with an accuracy of about a wavelength.

Citation Download Citation

Osami Sasaki, Norihiko Murata, Kazuhiro Akiyama, and Takamasa Suzuki "Sinusoidal wavelength-scanning interferometers using a superluminescent diode", Proc. SPIE 3745, Interferometry '99: Applications, (17 August 1999); https://doi.org/10.1117/12.357778

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available