In this paper we present the first emitter efficiency results for the thin film 40% Er‐1.5% Ho YAG (Yttrium Aluminum Garnet, Y3Al5O12) and 25% Ho YAG selective emitter at 1500 K with a platinum substrate. Spectral emittance and emissive power measurements were made (1.2<λ<3.2 μm). Emitter efficiency and power density are significantly improved with the addition of multiple rare earth dopants. Predicted efficiency results are presented for an optimized (equal power density in the Er, 4I15/2−4I13/2@ 1.5 μm, and Ho, 5I7−5I8@ 2.0 μm emission bands) Er‐Ho YAG thin film selective emitter. © 1995 American Institute of Physics.