We propose a novel liquid-core waveguide using water-based ferrofluids as the guiding layer in a symmetrical metal-cladding waveguide structure to investigate the magneto-optical effect of extremely dilute ferrofluids. Owing to the high sensitivity of the ultra-high-order modes, the reflection intensity can be effectively tuned even by a weak magnetic field and the modulated reflectivity exhibits no threshold behavior. Furthermore, by properly adjusting the transmission axes of the polarizer, the detected laser intensity can be magnetic-field independent because the refractive indices for ordinary and extraordinary rays vary oppositely under the external field.
© 2012 Optical Society of America
Original Manuscript: December 9, 2011
Revised Manuscript: January 17, 2012
Manuscript Accepted: January 18, 2012
Published: March 26, 2012
Jingjing Sun, Cheng Yin, Changping Zhu, Xianping Wang, Wen Yuan, Pingping Xiao, Xianfeng Chen, and Zhuangqi Cao, "Observation of magneto-optical effect in extremely dilute ferrofluids under weak magnetic field," J. Opt. Soc. Am. B 29, 769-773 (2012)