Modifications to blackbody radiation in a one-dimensional photonic bandgap structure

Summary form only given, as follows. The Planck blackbody law is usually derived in a large cavity limit in which the density of electromagnetic modes is treated in the free space continuum limit. However, in a one-dimensional (lD) photonic bandgap (PBG) material, the normal mode structure is manifestly different from in free space, and hence the form of the blackbody spectrum can be radically altered. We calculate the modified blackbody frequency and wave-number spectrum in the simple example of 1D thin-film GaAs/AlGaAs PBG structure. Specifically, we compute the cavity-modified blackbody distribution as a function of frequency and wavevector and compare it to the experiment. The total power and the Lambertian angular distribution can be drastically modified depending on the location of the bulk blackbody spectral peak with respect to the photonic bandgap. In Sample A, the spectral peak is aligned with the photonic band edge, leading to mission enhancement. In Sample B, the blackbody peak is centered at the bandgap leading to suppression of emission. In both cases the angular distribution differs from the Lambertian expected for a bulk thermal emitter.