Publications by authors named "Yikun Bu"

Article Synopsis
  • - A novel method is developed for creating structural colors that are not affected by the angle of light, using a unique ultra-thin bilayer absorber made of Ni and GeSbTe, which improves color purity and brightness.
  • - The design features a simplified five-layer structure that adjusts oxide layer thickness to achieve a wide range of vibrant colors while ensuring high color levels and consistency.
  • - The resulting devices, capable of producing colors like yellow, cyan, and magenta, show impressive performance under various angles and have potential applications in areas like displays, printing, and anti-counterfeiting with cost-effective mass production.
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We report the first demonstration, to the best of our knowledge, of visible mode-locked fiber laser using frequency-shifted feedback (FSF) with a visible α-BaTeMoO (α-BTM) crystal acousto-optic modulator (AOM). First, an α-BTM crystal is used as the visible high-quality AOM with a high diffraction efficiency of 85, a fast rise/fall time of 79/98 ns, and a low insertion loss of 0.2 dB at 635 nm.

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We report, to the best of our knowledge, the first demonstration of an O + E-band tunable watt-level bismuth-doped phosphosilicate fiber laser and its frequency doubling to tunable red laser. Benefiting from the two types of bismuth active centers associated with silicon and phosphorus introduced in one fiber, an ultrabroad gain is available in the designed low-water-peak bismuth-doped phosphosilicate fiber (Bi-PSF) pumped by a self-made 1239 nm Raman fiber laser. The high-efficiency tunable lasing is achieved with a maximum output power of 1.

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Although conventional fiber-cladding power strippers (CPSs) based on the techniques of high-index adhesive or corrosive liquids onto fiber inner cladding have been well developed, they are still facing challenges in special applications such as spaceborne or radiation-environment fiber lasers and amplifiers. In this paper, we propose and fabricate high-efficiency CPSs based on all-dielectric optical thin films. By numerically analyzing the propagation characteristics of cladding light at the thin film interface, we design a high-index CPS and CPS with single- and cascaded-layer films coated onto the fiber inner cladding, respectively.

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We report, for the first time to our knowledge, a compact continuous-wave all-fiber cyan laser. The all-fiber cavity consists of a 443-nm fiber-pigtail laser diode as pump source, a 4.5-cm single-clad Pr-doped fluoride fiber, and two custom-built dielectric-coated fiber-pigtail mirrors in the visible spectral region.

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Here we demonstrate a red structural color of a multilayer structure made of all silicon-based materials. By using amorphous silicon (a-Si) and silicon dioxide () with a large difference in the refractive index, high reflection efficiency can be achieved with only a few layers. The anti-reflection unit composed of top silicon monoxide (SiO) and layers can significantly reduce the reflection intensity of the non-target wavelengths to ensure that the device has good color saturation.

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In this paper, a multi-wavelength fiber ring laser (MWFRL) based on a hybrid gain medium and Sagnac interferometer (SI) used for temperature measurement has been proposed and experimentally demonstrated. Experiments have been carried out with polarization maintaining fibers (PMF) of different lengths, which are incorporated in the SI as sensing elements. Stable multi-wavelength oscillation at 1560 nm band is successfully achieved with the wavelength instability of ±0.

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Low threshold continuous-wave (CW) lasing of current injected InGaN quantum dot (QD) vertical-cavity surface-emitting lasers (VCSELs) was achieved at room temperature. The VCSEL was fabricated by metal bonding technique on a copper substrate to improve the heat dissipation ability of the device. For the first time, lasing was obtained at yellow-green wavelength of 560.

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For a linearly variable Fabry-Perot filter, the peak transmission wavelengths change linearly with the transverse position shift of the substrate. Such a Fabry-Perot filter is designed and fabricated and used as an output coupler of a c-cut Nd:YVO laser experimentally in this paper to obtain a 1062 and 1083 nm dual-wavelength laser. The peak transmission wavelengths are gradually shifted from 1040.

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We describe experimental results with a diode-pumped, passively Q-switched extracavity second- and third-harmonic generation. Cr:YAG is used as a saturable absorber for pulse generation. Taking into account the thermal effects of Nd:YAG at high incident pump power, we use a short plane-to-plane cavity configuration to take advantage of the maximum pump power and obtain the compactness structure.

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