Athermal photonic crystal membrane reflectors on diamond

We report here experimental demonstration of Fano resonance photonic crystal Si membrane reflectors on diamond for much improved thermal performance. At normal incidence, high reflection is obtained over a broad spectral band, with reflectivity greater than 95% from 1260 to 1450 nm. The measured reflection spectrum agrees well with the theoretical design. The improved thermal performance, with much reduced temperature rise, was also observed experimentally over a wide range of high incident optical power intensities. Such athermal Si membrane reflectors on diamond offer great opportunities for the applications in energy efficient lasers and high-power lasers.