Vertical resonant-cavity narrowband infrared thermal emitter

摘要

Unlike laser, spontaneous emission from bulk thermal sources is usually perceived to be incoherent and broadband. However, when subwavelength microstructures are fabricated on the surface of bulk thermal sources, the radiative characteristics can be greatly altered. In this paper, a vertical resonant-cavity narrowband thermal emitter, which is based on the theory of surface wave existing in the forbid band of the truncated one-dimensional photonic crystals, is proposed. The central wavelength, bandwidth (FWHM) and emittance at its central wavelength are 2μm, 4.3nm and nearly 100%, respectively. Theory explanation is given, and two types of numerical simulation methods (transfer matrix method (TMM) and finite difference time domain method (FDTD)) are adopted to simulate this structure. The numerical results obtained by these two different methods are consistent; therefore, the feasibility of this devised emitter is confirmed.