Multi-channel frequency-multiplication filter based on photonic crystal

The photonic crystal used for the filter was composed of ZnS and complex refractive index medium alternately. Numerical calculation of the transfer matrix shows that the transmission spectra of the photonic crystal is with following characteristics. When the optical thickness of the two medium is a quarter of the characteristic wavelength, there will be a narrow band transmission peak with the transmittance of 13.7 near the even frequency multiplications of the characteristic frequency. At the same time forbidden band appears on the other position of the spectra. When the number of cycles increases, the transmission peak slightly blue-shifts, but the peak value does not change. When the angle of incidence increases, the position of the transmission peak remains the same, and the peak value decreases. When the geometric thickness of the two medium changes at the same time, the transmission peak value remains the same, and the position changes. With the geometric thickness increases, blue-shift is observed at the transmission peak, and vice versa. These characteristics provides theoretical foundation for multi-channel frequency-multiplication filtering.