Coupled Tamm plasmon polaritons induced narrow bandpass filter with ultra-wide stopband

Narrow bandpass filters (NBPFs) play important roles in optics, such as quantum communication, spectrometer, and wavelength division multiplexing. However, the stopband and restraint ability of traditional NBPFs is limited. In this article, a coupled Tamm plasmon polaritons (TPPs) induced transmission theory has been proposed to design high-efficiency NBPFs with ultra-wide deep stopbands. An NBPF at 1.55 μm has been experimentally demonstrated with full width at half maximum (FWHM) of 10 nm and stopband ranging from 0.2 to 25 μm which is 62 times wider than that of traditional ones. Furthermore, the restraint depth of the stopband reaches 0.03%, which is only 1/20 of a traditional filter with the same FWHM. Its advantage in restraining ambient light over traditional ones has also been demonstrated with an InGaAs infrared detector. It provides a very powerful way to capture specific narrowband optical signals from ultra-wide strong ambient light, especially useful for daytime quantum communications.