by Prof. /Dr. Mohammad E. Khosroshahi, M. Shaikh.
Nanobiophotonies & Biomedical Research Lab,MIS Electronics Inc.
Abstract
Fiber optic sensors have gained enormous interest in research and development in biomedical applications, including diagnostic techniques and industrial usage such as smart structures to monitor various engineering and civil structural components due to their advantages of immunity from electromagnetic interference, real-time label-free detection, relatively easy instrumentation, and low cost. Optical heterodyne detection is a method of extracting information encoded as modulation of the phase, frequency, or both of electromagnetic radiation in the visible or infrared band. Heterodyne signifies more than one frequency, in contrast to the single frequency employed in homodyne detection. The comparison of the two light signals is typically achieved by combining them in a photodiode detector with a linear response. Typically, the two light frequencies are similar enough that their difference or beat frequency produced by the detector is in the radio or microwave band, which can be conveniently processed by electronic means.