A birefringence measurement system is introduced to get high phase resolution for detection of low contents of biochemicals. By using a fixed quarter-wave plate and a rotating polarizer, the phase difference between two orthogonal polarizations is transformed into phase delay of output sinusoidal signal. Analyzing the output phase, birefringence change could be detected with a phase noise of 0.14°. As well as the birefringence measurement system, an optical evanescent waveguide sensor was developed. A rib-type silica waveguide overlaid with TiO2 film was fabricated, and a developed birefringence measurement technique was employed in evaluating a refractive index change on waveguide surface. For the fabricated waveguide with a 40-nm-thick TiO2 film, experiment results showed that the minimum detectable index change was 5.9×10−7.
© 2009 Optical Society of America
Remote Sensing and Sensors
Original Manuscript: February 25, 2009
Manuscript Accepted: May 18, 2009
Published: June 29, 2009
Vol. 4, Iss. 9 Virtual Journal for Biomedical Optics
Geun-Sik Son, Woo-Kyung Kim, Woo-Seok Yang, Hyung-Man Lee, Han-Young Lee, Sung-Dong Lee, Woo-Jin Jeong, Soon-Woo Kwon, Ye-na Kim, and Sang-Shin Lee, "Birefringent waveguide sensor using a polarizer rotating technique," Opt. Lett. 34, 2045-2047 (2009)