INVESTIGATION OF OPTICAL RESONATORS AND BANDPASS FILTERS ON STRUCTURES MADE OF ALTERNATING LAYERS OF QUARTZ AND SILVER

The characteristics of a planar optical resonator made of quartz glass surrounded by silver mirrors were studied as their thickness varied. The frequency responses of bandpass filters were measured on planar structures obtained by vacuum deposition on quartz glass (SiO2) substrates of three quartz layers, which are half-wavelength resonators separated by four silver (Ag) layers from each other, from the substrate, and from free space. The thicknesses of the Ag and SiO2 layers were determined based on the specified parameters of the filter passband by synthesizing one-dimensional models using electrodynamic analysis. The experimental frequency dependences of the real and imaginary parts of the complex permittivity of silver were taken into account. The measured frequency responses of the manufactured prototypes of red, green, and purple filters are in good agreement with the characteristics obtained during synthesis. Systematic studies of filters with a central bandwidth frequency of 300 THz (wavelength of 1 µm) and a relative width of 2-20%, containing from 3 to 6 resonators, have been carried out. The high performance of the developed filters shows the prospects of their use in optical devices.