A Survey On The Design Of Thin Film Optical Bandpass Filter For Diagnosis In Aditya Tokamak

Thin film optical bandpass filters are widely used in Aditya Tokamak for the diagnosis of $\mathrm{H}\alpha$ and Carbon emission. In recent years, Fabry Perot based filters, polarization based filter and Bragg’s mirror based filters are cited in literatures for plasma diagnosis. Performance of these filters can be improved through optimization techniques like Particle Swarm optimization, Genetic Algorithm etc. However the major challenge lies in developing thin film optical bandpass filters for the desired Central WaveLength (CWL) and expected Full Width Half Maximum (FWHM). In this paper, a detailed literature survey is performed on the physics behind the design of optical band pass filters, optimization techniques and plasma diagnostics using optical filters.