Inverse design of all-dielectric parallel-plane mirror optical resonator

•All-dielectric optical resonator based on parallel mirrors is designed using inverse design algorithm.•Applied design approach intelligently generates Bragg-like reflection effect to create optical bandgap in a random structure.•Light was strongly confined using an optimization process dictated by an objective function.•The resonating structure exhibiting the expected field distribution (first-order mode) in the cavity region at a pre-defined wavelength was inversely designed without any conventional parametric analysis.•The proposed structure was generated by etching an Si layer on a silicon dioxide (SiO2) substrate of a standard semiconductor-on-insulator (SOI) wafer. The proposed structure had a compact configuration with a footprint of 13.394 × 0.592 μm2.•Inversely designed resonator can be used as a label-free refractive index-sensing device that is important in biophotonics and biosensing applications.