Transfer of photonic crystal membranes to a transparent gel substrate

We report a method of transferring 150 nm thick Al(0.35)Ga(0.65)As photonic crystal slabs to a transparent gel, without compromising their optical properties. We demonstrate successful transfer for membranes as large as ~ 425 × 425 μm(2). The transfer results in a 2.5% frequency red shift and increases the visibility of the resonances in reflection spectra. The avoided crossings between the modes show a subradiant mode with quality factors up to ~300. This suggests that the quality factor is only limited by the finite size of the crystal.