A5025007719- Spectroscopy and Laser Applications
- Atmospheric Ozone and Climate
- Gamma-ray bursts and supernovae
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Astrophysics and Cosmic Phenomena
- Scientific Measurement and Uncertainty Evaluation
- Atomic and Subatomic Physics Research
- Atmospheric and Environmental Gas Dynamics
- Advanced Sensor Technologies Research
- Radio Astronomy Observations and Technology
- Stellar, planetary, and galactic studies
- Photonic and Optical Devices
- Quantum optics and atomic interactions
- Cold Atom Physics and Bose-Einstein Condensates
- Advanced Fiber Laser Technologies
- Optical Systems and Laser Technology
- Advanced Measurement and Metrology Techniques
- Atomic and Molecular Physics
- Dark Matter and Cosmic Phenomena
- Chemical Thermodynamics and Molecular Structure
- Mass Spectrometry Techniques and Applications
- Astrophysics and Star Formation Studies
- Advanced Frequency and Time Standards
University of Science and Technology of China
2005-2025
Peking University
2022
State Key Laboratory of Nuclear Physics and Technology
2022
Hefei National Center for Physical Sciences at Nanoscale
2015-2021
CAS Key Laboratory of Urban Pollutant Conversion
2021
Chinese Academy of Sciences
2014-2017
National Institute of Metrology
2017
Shanghai Institute of Optics and Fine Mechanics
2017
China Meteorological Administration
2015
While most of the inter-galactic medium (IGM) today is permeated by ionized hydrogen, it was largely filled with neutral hydrogen for first 700 million years after Big Bang. The process that IGM (cosmic reionization) expected to be spatially inhomogeneous, fainter galaxies playing a significant role. However, we still have only few direct constraints on reionization process. Here report spectroscopic confirmation two and very likely third galaxy in group (hereafter EGS77) at redshift z =...
We present grism spectra taken with the Advanced Camera for Surveys to identify 29 red sources (i'-z') > 0.9 in Hubble Ultra Deep Field (HUDF). Of these 23 are found be galaxies at redshifts between z=5.4 and 6.7, identified by break 1216 angstrom due IGM absorption; two late type dwarf stars colors; four colors spectral shape similar dust reddened or old z~1-2. This constitutes largest uniform, flux-limited sample of spectroscopically confirmed such faint fluxes z'<27.5. Many also...
We present a multiwavelength analysis of Swift GRB 061007. The 2 m robotic Faulkes Telescope South began observing 137 s after the onset γ-ray emission, when optical counterpart was already decaying from R ~ 10.3 mag, and continued for next 5.5 hr. These observations begin during final flare continue through beyond long, soft tail emission whose flux shows an underlying simple power-law decay identical to that seen at X-ray wavelengths, with temporal slope α 1.7 (F ∝ t-α). This remarkably in...
The polarizability of the hydrogen molecule can be precisely calculated based on quantum electrodynamics (QED) theory and a few fundamental physical constants. Therefore, experimental measurements with comparable accuracy test establish gas metrology as working gas. An optical refractometer was built its performance tested by measuring electric dipole polarizabilities argon, neon, nitrogen. H2 determined to 2.031 027(71) cm3mol−1. result agrees current value, indicating potential primary...
Precise molecular transition frequencies are needed in various studies including the test of fundamental physics. Two well isolated ro-vibrational transitions 12C16O at 1.57 μm, R(9) and R(10) second overtone band, were measured by a comb-locked cavity ring-down spectrometer. Despite weakness lines (Einstein coefficient A≃0.008 s-1), Lamb-dip spectra recorded with signal-to-noise ratio over 1000, line positions determined to be 191 360 212 761.1 440 612 662.2 kHz, respectively, an...
We present a new method of comb-locked cavity ring-down spectroscopy for the Lamb-dip measurement molecular ro-vibrational transitions. By locking both probe laser frequency and temperature-stabilized high-finesse to an optical comb, we realize saturation molecules with kilohertz accuracy. The technique is demonstrated by recording R(9) line in υ = 3 − 0 overtone band CO near 1567 nm. spectrum such weak (transition rate 0.0075 s−1) obtained using input power only mW, position determined be...
We present our measurements of the H$\alpha$, [OIII], and [OII] luminosity functions as part Lyman Alpha Galaxies at Epoch Reionization (LAGER) survey using samples 1577 $z = 0.47$ H$\alpha$-, 3933 0.93$ [OIII]-, 5367 1.59$ [OII]-selected emission line galaxies in a single 3 deg$^2$ CTIO/Blanco DECam pointing COSMOS field. Our observations reach 5$\sigma$ depths $8.2\times10^{-18}$ erg s$^{-1}$ cm$^{-2}$ comoving volumes $(1-7)\times10^{5}$ Mpc$^3$ making one deepest narrowband surveys....
The (30012) ← (00001) band of 12C16O2 in the 1.6 μm region is used for satellite observation carbon dioxide Earth's atmosphere. Here, we report a Doppler-free spectroscopy study this with comb-locked wavelength-modulated cavity-enhanced absorption spectroscopy. Frequencies 18 transitions rotational quantum numbers up to 42 were determined sub-kHz accuracy, corresponding fractional uncertainty at 10-12 level. With precision, revealed an anomalous decrease line shift and increase broadening...
ABSTRACT The H α equivalent width (EW) is an observational proxy for specific star formation rate (sSFR) and a tracer of episodic, bursty star-formation activity. Previous assessments show that the EW strongly anticorrelates with stellar mass as M−0.25 similar to sSFR – relation. However, such correlation could be driven or even formed by selection effects. In this study, we investigate how distributions correlate physical properties galaxies biases alter correlations using z = 0.47...
Interactions between a molecule and two or more laser fields are of great interest in various studies, but weak highly overlapping transitions hinder precision measurements. We present the method comb-locked cavity-assisted double resonance spectroscopy based on narrow-linewidth continuous-wave lasers, which allows for state-selective pumping probing molecules. By locking near-infrared diode lasers to one cavity with finesse at order 105, we measured all three types resonances. Carbon...
The low divergent Dammann grating is researched for the potential applications in aerospace.A laserbeam writing system developed grating.The uniformity and efficiency of are presented this letter.The novelty letter to demonstrate a low-cost effective method fabricate grating.
Modal analysis of the 1 x 3 highly efficient reflective triangular grating operating in 800 nm wavelength under normal incidence for TE polarization is presented this Letter. The rigorous coupled wave and simulated annealing algorithm are used to design beam splitter. consists a mirror transmission on top. mechanism clarified by simplified modal method. Then, gratings fabricated direct laser writing lithography.
Quantitative measurement of water vapor is essential in many fields including semiconductor industry, combustion diagnosis, meteorology, and atmospheric studies. We present an optical hygrometer based on cavity ring-down spectroscopy. The instrument high-vacuum compatible, self-calibrated by using the free-spectral-range made low-thermal-expansion Invar. Using a single tunable diode laser working at 1.39 µm, detection trace vacuum high-purity helium gas, also determination humidity ambient...
Transitions of the 6ν3 overtone band 14N216O near 775 nm have been studied by continuous-wave cavity ring-down spectroscopy. Line positions and intensities were derived from a fit line shape using hard-collisional profile. The determined with absolute accuracy 5×10−4 cm−1 allowed us to reveal finer ro-vibrational couplings taking place after J>14 except strong anharmonic interaction identified effective Hamiltonian model. also retrieved an estimated 2% for majority unblended lines. A new set...
With the development of vacuum technology, subject to influence directional flow and uneven temperature, thermodynamic equilibrium state is destroyed. In this case, pressure reference not suitable for characterizing state. To ensure long-term stability reproducibility measurement system, metrology will be characterized by gas density. The precisive refractive index based on a Fabry-Perot cavity can used derive This kind an optical links macroscopic dielectric constants gases with microscopic...
We present a multiwavelength analysis of Swift GRB 061007. The 2-m robotic Faulkes Telescope South (FTS) began observing 137 s after the onset gamma-ray emission, when optical counterpart was already decaying from R 10.3 mag, and continued for next 5.5 hours. These observations begin during final flare continue through beyond long, soft tail emission whose flux shows an underlying simple power-law decay identical to that seen at X-ray wavelengths, with temporal slope alpha 1.7 This...
A gas pressure measurement device is built based on the refractive index method, and range from 10 kPa to 100 kPa, tested by a dual-cavity comparison method. The temperature of two vacuum chambers separately controlled cavities are connected ensure that pressures in same. Using high-purity nitrogen (6N) as medium, under condition different pressures, comparative measurements conducted. results show optical gauge has repeatability better than 30 × 10<sup>–6</sup>, which...