Wavelength-selective infrared detector fabricated by integrating LiTaO3 with a metamaterial perfect absorber

Abstract Pyroelectric infrared detectors are widely used owing to their uncooling characteristic and full infrared spectrum response. However, the increased volume and complex fabrication process due to the presence of an optical filter or resonant cavity, which is required to realize wavelength selection for every special application, makes it difficult to fabricate an integrated pyroelectric detector. Herein, we propose a wavelength-selective absorbing infrared detector in which a pyroelectric material is integrated with a metamaterial perfect absorber (MPA). A LiTaO3 single crystal with a metallic film on both sides was selected as the substrate, and a metal-dielectric-metal (MDM)-type MPA was deposited on its top. The MPA structure, consisting of a SiO2 dielectric layer and cross-type periodic units, provided a high selective absorption at 3.16 μm. With the incident radiation power transferred into heat by the dielectric layer and diffused into LiTaO3, a pyroelectric voltage was generated. This integration resulted in an infrared detector with a ∼90% absorption at 3.16 μm and a detectivity of 3.2 × 107 cm Hz1/2W−1 at 26.3 Hz.