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Register a new userTwo distinct approaches to tune multiple reflective bands of one-dimensional photonic crystal at normal incidence
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Two different methods are illustrated to tune multiple reflective bands. For both two types of one-dimensional (1D) photonic crystal (PC) construction, positions of multiple reflective bands can be regulated under certain principles. In addition, the 1D PC heterostructure could be adopted to modulate the relative intensities of reflectance between multiple reflective bands. Structural color is revealed by transforming reflection spectra into CIE coordinates, and the obtained results indicate that CIE coordinate shift occurs due to either band position change or band reflectance variation. The CIE coordinate shift behavior is also influenced by the number of multiple reflective bands. The two approaches reported in this work may provide insights for the application of 1D PC in areas such as displays, sensors, and decoration.
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We demonstrate two-dimensional photonic crystal cavities operating at telecommunication wavelengths in a single-crystal diamond membrane. We use a high-optical-quality and thin (~ 300 nm) diamond membrane, supported by a polycrystalline diamond frame, to realize fully suspended two-dimensional photonic crystal cavities with a high theoretical quality factor of ~ $8times10^6$ and a relatively small mode volume of ~2$({lambda}/n)^3$. The cavities are fabricated in the membrane using electron-beam lithography and vertical dry etching. We observe cavity resonances over a wide wavelength range spanning the telecommunication O- and S-bands (1360 nm-1470 nm) with Q factors of up to ~1800. Our method offers a new direction for on-chip diamond nanophotonic applications in the telecommunication-wavelength range.
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Color centers in diamond are promising spin qubits for quantum computing and quantum networking. In photon-mediated entanglement distribution schemes, the efficiency of the optical interface ultimately determines the scalability of such systems. Nano-scale optical cavities coupled to emitters constitute a robust spin-photon interface that can increase spontaneous emission rates and photon extraction efficiencies. In this work, we introduce the fabrication of 2D photonic crystal slab nanocavities with high quality factors and cubic wavelength mode volumes -- directly in bulk diamond. This planar platform offers scalability and considerably expands the toolkit for classical and quantum nanophotonics in diamond.
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