A5087394787- Spectroscopy and Laser Applications
- Advanced Fiber Laser Technologies
- Atomic and Molecular Physics
- Photonic and Optical Devices
- Disaster Management and Resilience
- Flood Risk Assessment and Management
- Atomic and Subatomic Physics Research
- Laser Design and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Semiconductor Lasers and Optical Devices
- Porphyrin and Phthalocyanine Chemistry
- Luminescence and Fluorescent Materials
- Advanced Frequency and Time Standards
- Atmospheric Ozone and Climate
- Synthesis and Properties of Aromatic Compounds
- Radiation Detection and Scintillator Technologies
- Muon and positron interactions and applications
- Strong Light-Matter Interactions
- Advanced Chemical Physics Studies
- Plasmonic and Surface Plasmon Research
- Nuclear physics research studies
- Infrastructure Resilience and Vulnerability Analysis
- Evacuation and Crowd Dynamics
- Metamaterials and Metasurfaces Applications
- Land Use and Ecosystem Services
California Institute of Technology
2021-2025
National Yang Ming Chiao Tung University
2014-2025
University of Wisconsin–Madison
2023-2024
United States Naval Research Laboratory
2021
Wrocław University of Science and Technology
2021
AGH University of Krakow
2021
National Tsing Hua University
2011-2021
University of Taipei
2019-2020
Mitchell Institute
2019
Texas A&M University
2019
Abstract The energy levels of hydrogen-like atomic systems can be calculated with great precision. Starting from their quantum mechanical solution, they have been refined over the years to include electron spin, relativistic and field effects, tiny shifts related complex structure nucleus. These caused by nuclear are vastly magnified in formed a negative muon nucleus, so spectroscopy these muonic ions used investigate high Here we present measurement two 2S–2P transitions helium-4 ion that...
Abstract Engineering asymmetric transmission between left-handed and right-handed circularly polarized light in planar Fabry–Pérot (FP) microcavities would enable a variety of chiral light-matter phenomena, with applications spintronics, polaritonics, lasing. Such symmetry breaking, however, generally requires Faraday rotators or nanofabricated polarization-preserving mirrors. We present simple solution requiring no nanofabrication to induce FP microcavities, preserving low mode volumes by...
We present direct frequency comb cavity ring-down spectroscopy with Vernier filtering as a straightforward approach to sensitive and multiplexed trace gas detection. The high finesse acts both extend the interaction length sample spectral filter, alleviating need for dispersive elements or an interferometer. In this demonstration, free running interband cascade laser was used generate centered at 3.3 μm covering ∼10 cm–1 (300 GHz), which coupled into high-finesse cavity, providing 0.9 km of...
The lack of intrinsic mirror symmetry in cavity mirrors poses a significant challenge for most organic chiral materials generating circularly polarized (CP) lasers. How ever, nonreciprocal chiroptical materials, such as the recently developed thin films exhibiting Apparent Circular Dichroism (ACD), provide promising approach to CPlight generation. In this work, we integrate an ACD-based film into free-space dye laser cavity, achieving direct CP emission with degree circular polarization...
Hydrogen-like light muonic ions, in which one negative muon replaces all the electrons, are extremely sensitive probes of nuclear structure, because large mass increases tremendously wave function overlap with nucleus. Using pulsed laser spectroscopy we have measured three 2S-2P transitions helium-3 ion ($\mu^3$He$^+$), an formed by a and bare This allowed us to extract Lamb shift $E(2P_{1/2}-2S_{1/2})= 1258.598(48)^{\rm exp}(3)^{\rm theo}$ meV, 2P fine structure splitting $E_{\rm FS}^{\rm...
Precision spectroscopy of light muonic atoms provides unique information about the atomic and nuclear structure these systems thus represents a way to access fundamental interactions, properties constants. One application comprises determination absolute charge radii with unprecedented accuracy from measurements 2S - 2P Lamb shift. Here, we review recent results extracted hydrogen helium present experiment proposals Z ≥ 3. In addition, our approaches towards precise measurement Zemach in...
We review the status of proton charge radius puzzle. Emphasis is given to various experiments initiated resolve conflict between muonic hydrogen results and from scattering regular spectroscopy.
Chip-scale optical frequency combs can provide broadband spectroscopy for diagnosing complex organic molecules. They are also promising as miniaturized laser spectrometers in applications ranging from atmospheric chemistry to geological science and the search extraterrestrial life. While cavities commonly used boost sensitivity, it is challenging realize a compact cavity-enhanced comb-based spectrometer. Here, we apply Vernier technique free-running operation of an interband cascade comb...
The absolute frequency measurement of thallium $6{P}_{1/2}\ensuremath{\rightarrow}7{S}_{1/2}$ transitions using a self-referencing optical comb is reported. Our results can be used as benchmark for the accurate wave-function calculations heavy atoms, and then improve atomic parity-nonconservation amplitude. centers have been precisely determined by Doppler-free saturation spectroscopy utilizing pair counterpropagating laser beams intersecting with beam. We achieved determination transition...
The dependence of reflectance on the morphology Si nanowire (SiNW) arrays was investigated. Several samples including vertically aligned NW and bunched NWs were prepared by a combination wet etching process two types drying process. optical depended length aggregation degree NWs. with high reduced to less than 8% in long visible wavelength range. It is considered that significant reduction ascribed macrostructure
Avalanche photodiodes are commonly used as detectors for low energy x-rays. In this work, we report on a fitting technique to account different detector responses resulting from photoabsorption in the various avalanche photodiode layers. The use of results an improvement resolution at 8.2 keV by up factor 2 and corrects timing information 25 ns space dependent electron drift time. addition, waveform analysis is particle identification, e.g., distinguish between x-rays MeV electrons our experiment.
One of the most precisely determined upper limits for electron electric dipole moment (EDM) is set by thallium (Tl) atomic beam experiment. way to enhance sensitivity setup laser cool Tl atoms reduce EDM-like phase caused E$\ifmmode\times\else\texttimes\fi{}$v effect. In this report, a cooling scheme based on $6{P}_{3/2}(F=2)\ensuremath{\leftrightarrow}6{D}_{5/2}({F}^{\ensuremath{'}}=3)$ transition in proposed. The absolute frequency measurement nearly closed-cycle was performed an...
Purpose The purpose of this paper is to explore the effects place attachment and risk perception with bounded rationality on willingness live in a high-earthquake-risk area. Design/methodology/approach study establishes hypothetical model basis theory planned behavior, perception. A structural equation (SEM) measures relationships between variables. Findings Place affects individuals their preferences; it makes them willing continue living areas. Additionally, (fatalism optimism bias) might...
We report a spectrometer employing optically switched dual-wavelength cavity ring-down spectroscopy (OSDW-CRDS) for high-precision measurements of methane isotope ratios. A waveguide optical switch rapidly alternated between two wavelengths to detect absorption by isotopologues using near-infrared CRDS. This approach alleviated common-mode noise that originated primarily from temperature and frequency fluctuations. demonstrated the measurement δD in natural abundance precision 2.3 ‰, despite...
We report on the Doppler-free saturation spectroscopy of nitrous oxide (N$_2$O) overtone transition at 1.28~$\mu$m. This measurement is performed by noise-immune cavity-enhanced optical heterodyne molecular (NICE-OHMS) technique based quantum-dot (QD) laser. A high intra-cavity power, up to 10~W, reaches limit line using an cavity with a finesse 113,500. At pressure several mTorr, dip observed full width half-maximum about 2~MHz and signal-to-noise ratio 71. To best our knowledge, this first...
To access the wavelength within 1.1-1.3 μm region, we have developed a quantum-dot (QD) laser with an external-cavity configuration and linewidth of kilohertz at 1 ms integration time. The residual electroluminescence, due to inhomogeneous broadening QD gain medium, was observed filtered out using grating. While fiber-coupled electro-optical modulator employed, this system locked high-finesse (F∼18,500) optical cavity, noise-immune cavity-enhanced heterodyne molecular spectroscopy used...
We demonstrate a tunable external cavity tapered amplifier laser (ECTAL) using narrowband interference filter as the wavelength discriminator. The is over range from 1006 to 1031 nm with an output power of ∼1 W. amplified stimulated emission system suppressed better than 32 dB. applied study saturation spectroscopy on R(39) 57-0 line iodine molecule, which, our best knowledge, first measurement this close dissociation limit. linewidth a1 component ∼2 MHz at vapor pressure ∼11 Pa, and...
Abstract. Resilience, which has rapidly become an area of interest in multiple disciplines, is regarded as being key disaster mitigation and adaptation. The objective-indicator framework a common way to evaluate resilience, but limited attention been paid measuring the risk perceptions adaptation behaviors individuals. In addition, due limitations related predicting potential earthquake events, past studies have placed more emphasis on predisaster discussions. Fortunately, this paper...
A frequency-stabilized ultraviolet laser system, locked to the thallium resonant transition of 377.5 nm, was demonstrated using a novel bichromatic spectroscopy technique for tuning zero-crossing laser-lock point. The atomic system is promising candidate in parity violation and permanent electric dipole moment experiments, its nm 6P1/2->7S1/2 important cooling trapping experiment. pressure shift, owing high buffer gas hollow-cathode lamp, observed an beam resonance as reference. Such shift...
We report on the method of sideband amplitude modulation (SAM) to achieve high-sensitivity spectroscopy with a fiber electro-optic modulator (fiber-EOM). This increases signal noise ratio (SNR) by factor forty, comparing conventional absorption spectroscopy. It is temporal balanced detection eliminate intensity light source, and capable preserving an undistorted Doppler profile for further quantitative analysis. Taking advantage newly developed fiber-EOM, SAM applicable various...