We demonstrated a narrow-linewidth high-power Yb-doped polarization-maintaining (PM) fiber laser with near-diffraction-limited beam. The laser system consisted of a phase-modulated single-frequency seed source and four-stage amplifiers in the master oscillator power amplifier configuration. A quasi-flat-top pseudo random binary sequence (PRBS) phase-modulated single-frequency laser with a linewidth of 8 GHz was injected into the amplifiers for suppressing stimulated Brillouin scattering.
View Article and Find Full Text PDFBackground: Eosinophilic chronic rhinosinusitis (ECRS) is a subtype of chronic rhinosinusitis (CRS) and is a refractory or intractable disease. However, a reliable clinical marker or an effective treatment strategy has not yet been established. ECRS is accompanied by excessive eosinophil infiltration and Th2 inflammatory response, which is closely related to tissue remodeling in the upper airways.
View Article and Find Full Text PDFWe fabricated a fiber-optic directional coupler based on evanescent field coupling between side-polished large mode area (LMA) double clad fibers (DCFs) for a high power fiber laser. The tapping ratio of the fabricated coupler was measured to be - 32 dB. The fundamental mode coupled in a core of the lower side-polished fiber (SPF) was transferred to the upper SPF without clad-mode coupling.
View Article and Find Full Text PDFHuman skin provides an interface that transduces external stimuli into electrical signals for communication with the brain. There has been considerable effort to produce soft, flexible, and stretchable electronic skin (E-skin) devices. However, common polymers cannot imitate human skin perfectly due to their poor biocompatibility, biofunctionality, and permeability to many chemicals and biomolecules.
View Article and Find Full Text PDFWe present a wafer-scale array of resonant coaxial nanoapertures as a practical platform for surface-enhanced infrared absorption spectroscopy (SEIRA). Coaxial nanoapertures with sub-10 nm gaps are fabricated via photolithography, atomic layer deposition of a sacrificial AlO layer to define the nanogaps, and planarization via glancing-angle ion milling. At the zeroth-order Fabry-Pérot resonance condition, our coaxial apertures act as a "zero-mode resonator (ZMR)", efficiently funneling as much as 34% of incident infrared (IR) light along 10 nm annular gaps.
View Article and Find Full Text PDFIn this paper, we report the development of an optical sensor network (OSN) based on piezoelectrically actuated corner cube retroreflectors (PA-CCRs). PA-CCRs were fabricated by microelectromechanical systems processes and assembled by aligning horizontally actuated mirrors and vertical side walls in a holder, which allows mass production. Fabricated PA-CCRs showed a tilting angle by more than 1.
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