A5046065065- Advanced Fiber Laser Technologies
- Spectroscopy and Laser Applications
- Photonic and Optical Devices
- Analytical Chemistry and Sensors
- Mass Spectrometry Techniques and Applications
- Atomic and Subatomic Physics Research
- Advanced Frequency and Time Standards
- Advanced Fiber Optic Sensors
- Cold Atom Physics and Bose-Einstein Condensates
- Molecular Spectroscopy and Structure
- Laser-Matter Interactions and Applications
- Advanced Chemical Physics Studies
- Oral and Maxillofacial Pathology
- Atomic and Molecular Physics
- Mechanical and Optical Resonators
- Cleft Lip and Palate Research
- Laser Design and Applications
- Orthodontics and Dentofacial Orthopedics
- Spectroscopy and Quantum Chemical Studies
- Analytical Chemistry and Chromatography
- Bone health and treatments
- Advanced Photonic Communication Systems
- Scientific Measurement and Uncertainty Evaluation
- Photonic Crystal and Fiber Optics
- Electrochemical Analysis and Applications
Institute of Physics
2018-2024
Nicolaus Copernicus University
2018-2024
National Institute of Advanced Industrial Science and Technology
2021-2024
Yokohama City University
2020
Gifu University
2020
Kyoto University
2019-2020
University of Electro-Communications
2015-2020
Japan Science and Technology Agency
2016-2019
Japan Society for the Promotion of Science
2016-2019
Uganda Episcopal Conference
2019
We search for ultralight scalar dark matter candidates that induce oscillations of the fine structure constant, electron and quark masses, quantum chromodynamics energy scale with frequency comparison data between a $^{171}\mathrm{Yb}$ optical lattice clock $^{133}\mathrm{Cs}$ fountain microwave span 298 days an uptime 15.4%. New limits on couplings to electrons gluons in mass range from ${10}^{\ensuremath{-}22}$ ${10}^{\ensuremath{-}20}\text{ }\text{ }\mathrm{eV}/{c}^{2}$ are set, assuming...
We demonstrate rapid characterization of complex optical properties solids via dual-comb spectroscopy (DCS) in the near-infrared region. The fine spectral structures refractive index an Er:YAG are successfully deduced using developed system and Fourier analysis. Moreover, simultaneous determination thickness is demonstrated for a silicon semiconductor wafer through use multireflected echo signals. results indicate potential DCS as powerful measurement tool full solid materials.
We present a Doppler-free high-resolution dual-comb spectroscopy technique in which system is employed to perform optical-optical double-resonance (OODR) spectroscopy. In our experimental study, and high-frequency-accuracy broadband measurements were realized using the proposed OODR spectroscopic technique, does not require high-power-per-mode frequency combs. observed fully resolved hyperfine spectra of 5P3/2 - 4D5/2, 4D3/2 transitions Rb at 1530 nm precisely determined absolute frequencies...
Cavity ring-down spectroscopy is a ubiquitous optical method used to study light-matter interactions with high resolution, sensitivity and accuracy. However, it has never been performed the multiplexing advantages of direct frequency comb without significantly compromising spectral resolution. We present dual-comb cavity (DC-CRDS) based on parallel heterodyne detection signals local oscillator yield absorption dispersion spectra. These spectra are obtained from widths positions modes. two...
We report the most accurate measurement of position weak quadrupole S(2) 2-0 line in D$_2$. The spectra were collected with a frequency-stabilized cavity ring-down spectrometer (FS-CRDS) an ultra-high finesse optical ($\mathcal{F}$ = 637 000) and operating frequency-agile, rapid scanning spectroscopy (FARS) mode. Despite working Doppler-limited regime, we reached 40 kHz statistical uncertainty 161 absolute accuracy, achieving highest accuracy for homonuclear isotopologues molecular hydrogen....
Abstract We report improved absolute frequency measurement of the 1 S 0 - 3 P transition 171 Yb at National Metrology Institute Japan (NMIJ) by comparing optical lattice clock NMIJ-Yb1 with 13 Cs primary standards via International Atomic Time from August 2021 to May 2023. The measured is 518 295 836 590 863.62(10) Hz a fractional uncertainty 1.9 × 10 -16 , in good agreement recommended as secondary representation second. This 2.6 times lower than our previous uncertainty, and slightly any...
We report on the achievement of a reduced time difference in scale with respect to Coordinated Universal Time (UTC) by steering hydrogen-maser-based near-continuously operating optical lattice clock. The is generated postprocessing analysis for 230 days using hydrogen maser its fractional frequency stability limited flicker floor $2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}15}$ and an $\mathrm{Yb}$ clock operated uptime 81.6%. During 230-day period, root-mean-square our UTC 0.52...
In this study, we demonstrated an improvement in the detection sensitivity of dual-comb spectroscopy using repetition rate multiplication optical frequency combs. We compared signals three setups consisting combinations two combs with and without mode-filtering, investigated how influences signal-to-noise ratio (SNR) measurements. The high-repetition-rate enabled absorption lines HCN gas to be measured a high SNR short averaging time, real-time spectral data acquisition was realized...
Measurements of isotope shifts have recently been attracting considerable attention due to their potentials in searching for new forces. We report on the $4{f}^{14}6{s}^{2} {}^{1}{S}_{0}--4{f}^{13}5d6{s}^{2}(J=2)$ transition at 431 nm Yb, based absolute frequency measurements with an accuracy $\ensuremath{\approx}10$ kHz. With these data, hyperfine constants $^{173}\mathrm{Yb}$ are determined. To analyze data further, electronic structure ytterbium is theoretically calculated. The nuclear...
Abstract The recently concluded collaborative European project “Robust optical clocks for international timescales” (ROCIT) tackled some of the key challenges on roadmap towards a redefinition SI second. This paper gives an overview progress made improving robustness and automation verifying their uncertainty budgets through coordinated comparison campaigns. It also presents work incorporation into time scales, covering both use to steer local physical scales evaluations hydrogen masers...
We demonstrated Doppler-free two-photon absorption dual-comb spectroscopy of 5S1/2 - 5D5/2 and 5D3/2 transitions Rb. employed simple pulse-shaping the source eliminated Doppler-broadening backgrounds, which cause fitting errors signals. Moreover, to improve sensitivity, we investigated coherence in fluorescence signals coherent averaging method was applied detection for first time. The sensitivity significantly improved by reduce noise floor. Observed spectra fitted Voigt profiles performed...
The absolute frequency for a clock transition at 431 nm in ${}^{171}$Yb with an excited electron $f$ orbital is measured relative accuracy of 1x10^{-11}. Magnetic properties the transition, $g$ factor, and hyperfine splitting are also measured. intended to be used as test time variation fine-structure constant other fundamental physics searches.
Abstract Non-thermal molecular plasmas play a crucial role in numerous industrial processes and hold significant potential for driving essential chemical transformations. Accurate information about the composition of distribution populations among quantum states is understanding optimizing plasma processes. Here, we apply mid-infrared frequency comb-based Fourier transform spectrometer to measure high-resolution spectra containing hydrogen, nitrogen, carbon source 2800–3400 cm –1 range. The...
We developed a high resolution laser spectroscopic system to study detailed structures and dynamics in excited states of molecules. The cooperation an optical frequency comb single-mode dye realized resolution, accuracy, wide tuning range simultaneously with short measurement time easy operation. To demonstrate the ability our system, we observed hyperfine spectra B–X rovibronic transitions molecular iodine distributed 570–612 nm. absolute frequencies components were determined uncertainty...
This study objectives to investigate the influence of average energy intake at 1 week hospitalization on prognosis for older adults with pneumonia.
We developed a high-precision frequency-measurement system for continuously scanning single-mode cw lasers. The high precision wide frequency range is realized by employing an optical comb. operates as strong tool analyzing the spectral profile and scan characteristics of lasers, which suitable high-resolution molecular spectroscopy. demonstrated ability our with Doppler-free spectroscopy iodine.
Direct-comb spectroscopy techniques uses optical frequency combs (OFCs) as spectroscopic light source. They deliver high sensitivity, resolution and precision in a broad spectral range. Due to these features, the field has burgeoned recent years. In this work we constructed an OFC-based cavity-enhanced Fourier-transform spectrometer near-infrared region used it for line-shape study of rovibrational transitions CO perturbed by Ar. The highly sensitive measurements spanned wavenumber range...
We developed a mode-filtering technique based on the all-fiber-based external cavity for fiber-based optical frequency comb high repetition rate (frep) comb, and carrier envelope offset (fceo) can be detected stabilized is robust to environmental fluctuations. To achieve multiplication of frep with factor using fiber ring cavity, long was mitigate physical limitation inhibiting shortening length. In this study, length set 6.7 m (free spectral range = 44.7 MHz) as 6.1 m. were able demonstrate...
We apply an intensity-modulation technique to dual-comb spectroscopy improve its detection sensitivity. The scheme is demonstrated via Doppler-free optical-optical double-resonance of Rb by modulating the intensity a pump laser with frequencies set at rates 3 times lower and 50,000 higher than difference in repetition two frequency combs. signal-to-noise ratios are enhanced 6 for slow fast modulations, respectively, compared those conventional without any modulation. widely applicable...