Dual-channel optical filter based on photonic crystal with double defect

In the short note, we theoretically analyze a one-dimensional photonic crystal (1D PC) with a double defect structure for potential use in dual-channel optical filtering. Using the transfer matrix method, we calculate the transmission spectrum and identify two distinct peaks within the photonic band gap region, each corresponding to one of the defects. We also explore the impact of varying the number of unit cells between these defects. Our results suggest that this 1D PC with a double defect structure can serve as an effective tuned dual-channel optical filter.