| Time: | December 13, 2023 |
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Abstract:
We demonstrate low-cost, scalable manufacturing of optical metasurfaces with three approaches:
1) increasing a refractive index of resin with dielectric particle embedding for single-step nanoimprinting[1-5],
2) suppressing optical losses of hydrogenated amorphous silicon (a-Si:H) to apply complementary-metal-oxide-semiconductor technologies[6], and
3) high-index atomic layer deposited (ALD) structural resin[7].
We demonstrate the effectiveness of these materials in creating optical metasurfaces operating at different wavelengths in the infrared, visible, and ultraviolet spectra. Firstly, we achieve high efficiencies of up to 90.6%, 47%, and 60% with a-Si[1], TiO2[2-4], and ZrO2 PER[5] at wavelengths of 940, 532, and 325 nm, respectively. Furthermore, we obtain a measured efficiency of 30% at a wavelength of 248 nm using ZrO2 PER metasurfaces[5]. Secondly, by adjusting the deposition conditions of plasma-enhanced chemical vapor deposition, we engineer the bandgap of a-Si:H to enable low-loss operation, with minimum extinction coefficients as low as 0.082 at 450 nm[6]. Using low-loss a-Si:H, we demonstrate efficient beam-steering metasurfaces with measured efficiencies of 42%, 65%, and 75% at 450, 532, and 635 nm, respectively, marking the first Si-typed metasurfaces working at the full visible. Finally, we manufacture highly efficient metalenses using hybrid ALD structural resin with deep-ultraviolet lithography at visible wavelengths. Their measured efficiencies approach 60.9%, 77.8%, and 64.8% at 450, 532 and 635 nm, making them suitable for ultrathin virtual reality devices. Our approaches using PER[1-5], low-loss a-Si:H[6], and hybrid ALD structural resin[7] enables the low-cost, large-area manufacturing of efficient optical metasurfaces across different wavelengths, facilitating the commercialization of metasurface-based photonic devices[8-13].