68 citations · 305 across the 14 of their papers we have counts for
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Improved absolute frequency measurement of Yb at NMIJ with uncertainty below
Takumi Kobayashi, Akiko Nishiyama, Kazumoto Hosaka +6
We report improved absolute frequency measurement of the SP transition of Yb at National Metrology Institute of Japan (NMIJ) by comparing the $^{171}…
Generation of a precise time scale assisted by a near-continuously operating optical lattice clock
Takumi Kobayashi, Daisuke Akamatsu, Kazumoto Hosaka +8
We report on a reduced time variation of a time scale with respect to Coordinated Universal Time (UTC) by steering a hydrogen-maser-based time scale with a near-continuously operat…
Isotope-shift analysis with the transition in ytterbium
Akio Kawasaki, Takumi Kobayashi, Akiko Nishiyama +2
Measurements of isotope shifts have recently been attracting considerable attention due to their potentials in searching for new forces. We report on the isotope shifts of the $4f^…
Observation of the clock transition at 431 nm in Yb
Akio Kawasaki, Takumi Kobayashi, Akiko Nishiyama +2
We report on the observation of the transition at 431 nm in Yb by depleting atoms in a magneto-optical trap formed by the $6s^{2…
Search for ultralight dark matter from long-term frequency comparisons of optical and microwave atomic clocks
Takumi Kobayashi, Akifumi Takamizawa, Daisuke Akamatsu +8
We search for ultralight scalar dark matter candidates that induce oscillations of the fine structure constant, the electron and quark masses, and the quantum chromodynamics energy…
Uncertainty evaluation of an Yb optical lattice clock at NMIJ
Takumi Kobayashi, Daisuke Akamatsu, Yusuke Hisai +6
We report an uncertainty evaluation of an Yb optical lattice clock with a total fractional uncertainty of , which is mainly limited by the lattice-induce…
Dual-Mode Operation of an Optical Lattice Clock Using Strontium and Ytterbium Atoms
Daisuke Akamatsu, Takumi Kobayashi, Yusuke Hisai +4
We have developed an optical lattice clock that can operate in dual modes: a strontium (Sr) clock mode and an ytterbium (Yb) clock mode. Dual-mode operation of the Sr-Yb optical la…
A frequency-stabilized light source at 399 nm using an Yb hollow-cathode lamp
Takehiko Tanabe, Daisuke Akamatsu, Hajime Inaba +5
We demonstrate a diode laser system operating at 399 nm that is stabilized to the electric dipole transition in ytterbium (Yb) atoms in…
Second harmonic generation at 399 nm resonant on the transition of ytterbium using a periodically poled LiNbO waveguide
Takumi Kobayashi, Daisuke Akamatsu, Yoshiki Nishida +4
We demonstrate a compact and robust method for generating a 399-nm light resonant on the transition in ytterbium using a single-pass periodically poled LiNbO$…
Absolute frequency measurements and hyperfine structures of the molecular iodine transitions at 578 nm
Takumi Kobayashi, Daisuke Akamatsu, Kazumoto Hosaka +6
We report absolute frequency measurements of 81 hyperfine components of the rovibrational transitions of molecular iodine at 578 nm using the second harmonic generation of an 1156-…
Improved frequency measurement of the - clock transition in Sr using the Cs fountain clock at NMIJ as a transfer oscillator
Takehiko Tanabe, Daisuke Akamatsu, Takumi Kobayashi +10
We performed an absolute frequency measurement of the - transition in Sr with a fractional uncertainty of , which is less than one thi…
Frequency ratio measurement of 171Yb and 87Sr optical lattice clocks
Daisuke Akamatsu, Masami Yasuda, Hajime Inaba +4
The frequency ratio of the 1S0(F=1/2)-3P0(F=1/2) clock transition in 171Yb and the 1S0(F=9/2)-3P0(F=9/2) clock transition in 87Sr is measured by an optical-optical direct frequency…