Publications by authors named "Ying-Lung Daniel Ho"

Hexagonal boron nitride is rapidly gaining interest as a platform for photonic quantum technologies, due to its two-dimensional nature and its ability to host defects deep within its large band gap that may act as room-temperature single-photon emitters. In this review paper we provide an overview of (1) the structure, properties, growth and transfer of hexagonal boron nitride; (2) the creationof colour centres in hexagonal boron nitride and assignment of defects by comparison with calculations for applications in photonic quantum technologies; and (3) heterostructure devices for the electrical tuning and charge control of colour centres that form the basis for photonic quantum technology devices. The aim of this review is to provide readers a summary of progress in both defect engineering and device fabrication in hexagonal boron nitride based photonic quantum technologies.

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To achieve the modification of photonic band structures and realize the dispersion control toward functional photonic devices, composites of photonic crystal templates with high-refractive-index material are fabricated. A two-step process is used: 3D polymeric woodpile templates are fabricated by a direct laser writing method followed by chemical vapor deposition of MoS. We observed red-shifts of partial bandgaps at the near-infrared region when the thickness of deposited MoS films increases.

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Three-dimensional nanostructured magnetic materials have recently been the topic of intense interest since they provide access to a host of new physical phenomena. Examples include new spin textures that exhibit topological protection, magnetochiral effects and novel ultrafast magnetic phenomena such as the spin-Cherenkov effect. Two-photon lithography is a powerful methodology that is capable of realising 3D polymer nanostructures on the scale of 100 nm.

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We show that micron-scale two-dimensional (2D) honeycomb microwells can significantly improve the stability of blue phase liquid crystals (BPLCs). Polymeric microwells made by direct laser writing improve various features of the blue phase (BP) including a dramatic extension of stable temperature range and a large increase both in reflectivity and thermal stability of the reflective peak wavelength. These results are mainly attributed to the omnidirectional anchoring of the isotropically oriented BP molecules at the polymer walls of the hexagonal microwells and at the top and bottom substrates.

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