Design of an optoelectronic refractometer having an adjustable range of refractive index measurement

A real-time optoelectronic refractometer having an adjustable range of refractive index measurement is presented. The adjustment is achieved by obtaining a shift in the zero-reflected intensity point at the interface following the introduction of a glass plate of refractive index different from that of the constituent prism. The sensitivity remains reasonably high over the enhanced range of refractive index measurement. The experimental results are in qualitative agreement with the theoretical calculations. This refractometer sensor, which is based on the detection of modulation in emergent light intensity, has a sturdy and user-friendly design.