Fig. 1.

(A) Simulated normal emittance for W PhC Design I (r = 0.45 μm, a = 1.10 μm, d = 1.50 μm), W PhC Design II (r = 0.55 μm, a = 1.30 μm, d = 2.10 μm), W PhC Design III (r = 0.625 μm, a = 1.40 μm, d = 2.80 μm) with the first emittance peak in the vicinity of 1.7, 2.0, and 2.3 μm, respectively. A dramatic enhancement of the emittance (i.e., near blackbody performance below the cutoff wavelength) is evident compared to flat tungsten. (B) Average emittance below the cutoff wavelength (i.e., λ ≤ 2 μm) as a function of polar angle for W PhC Design II. As can be seen, the emitter mainly radiates in the direction close to normal.