Lithography-free planar band-pass reflective color filter using a series connection of cavities

In this article, a lithography-free multilayer based color flter is realized using a proper series connection of two cavities that shows relatively high efciency, high color purity, and a wide view angle. The proposed structure is a metal-insulator-metal-insulator-semiconductor (MIMIS) design. To optimize the device performance, at the frst step, transfer matrix method (TMM) modeling is utilized to fnd the right choices of materials for each layer. Simulations are carried out later on to optimize the geometries of the layers to obtain our desired colors. Finally, the optimized devices are fabricated and experimentally characterized to evaluate our modelling fndings. The characterization results of the fabricated samples prove the successful formation of efcient and wide view angle color flters. Unlike previously reported FP based designs that act as a band-stop flter in refection mode (absorbing a narrow frequency range and refecting the rest of the spectrum), this design generates a specifc color by refecting a narrow spectral range and absorbing the rest of the spectrum. The fndings of this work can be extended to other multilayer structures where an efcient connection of cavities in a tandem scheme can propose functionalities that cannot be realized with conventional FP resonators.