[OPTICAL REVIEW Vol. 7, No. 3 (2000) 199-204]
Spectral Criteria for Design of an Optical Modulator Based on Frustrated Total Internal Reflection
J. A. ORTEGA, J. A. CHÁVEZ, J. SALAZAR, A. TURÓ and M. J. GARCÍA
Sensor System Group, Department of Electronic Engineering, Polytechnic University of Catalonia, 08222 Terrassa, Spain
(Received September 21, 1999; Accepted February 17, 2000)
The spectral study of an optical modulator based on the frustrated total internal reflection is presented under static and dynamic conditions. An optical modulator based on macroscopic moving parts makes spectrometers voluminous and has low compactness. The use of static or quasi-static optical modulators, such as the one proposed in this paper, avoids these problems. The study under static conditions reveals that the modulator equalises the spectral emittance of a black body. The modulation efficiency is defined by comparing the modulator with an ideal square chopper. Study under dynamic conditions reveals spectral criteria that must be met in the design of the mechanical system of the modulator to shift the maximum value of the modulation efficiency to the desired wavelength.
Key words : frustrated total internal reflection, optical spectrum analysis, optical modulators, infrared spectroscopy, spectrometers