Here, we introduce low-loss hydrogenated amorphous silicon (a-Si:H), whose bandgap is optimized to suppress their extinction coefficient at visible frequencies. The bandgap of a-Si:H has been manipulated by adjusting the deposition parameters of plasma-enhanced chemical vapor deposition. Low-loss a-Si:H have been applied for beam-steering metasurfaces at the entire visible spectrums. Beam steering metasurface has achieved measured efficiencies of 42%, 65%, and 75% at the wavelengths of 450, 532, and 635 nm, respectively.
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