230 citations · 830 across the 16 of their papers we have counts for
17 papers
Orthoexciton-to-paraexciton conversion rate in CuO at sub-Kelvin temperatures
Yusuke Morita, Yukihiro Akiyama, Yuki Haita +2
We measured the conversion rate from 1s orthoexcitons to 1s paraexcitons in CuO below 1 K using a dilution refrigerator. To determine the conversion rate, we performed time-res…
Simulation of positronium laser cooling using the Lindblad master equation
Kenji Shu, Sohma Shiraishi, Kosuke Yoshioka
We present a formulation and numerical results for positronium (Ps) laser cooling. The formulation is based on the Lindblad master equation and follows the time evolution of the de…
Development of an optimal laser for chirp cooling of positronium based on chirped pulse-train generator
Kenji Shu, Naoki Miyamoto, Yuto Motohashi +3
We report the development and characterization of a pulsed 243 nm laser that is optimal for the cooling of positronium (Ps). The laser, which is based on the recent chirped pulse-t…
Dual optical frequency combs with ultra-low relative phase jitters from 550 nm to 1020 nm for precision spectroscopy
Eunmi Chae, Kota Nakashima, Kosuke Yoshioka
Here, ultra-low relative phase jitters over a wide optical spectrum were achieved for dual Ti:Sapphire optical frequency combs. The two optical frequency combs were independently p…
Temperature Study of Rydberg Exciton Optical Properties in Cu2O
Dungeon Daniel Kang, Aaron Gross, HeeBong Yang +4
Rydberg excitons in Cu2O can be an emergent platform for solid-state quantum information processing by utilizing the exaggerated properties of high-lying excited states within the…
A compact green Ti:Sapphire astro-comb with 43-GHz repetition frequency
Eunmi Chae, Eiji Kambe, Kentaro Motohara +3
A compact green astro-comb with 43-GHz repetition rate is developed based on a Ti:Sapphire optical frequency comb (OFC) and a mode-selecting cavity. The OFC's large repetition rate…
Geometrical analysis of Kerr-lens mode-locking for high-peak-power ultrafast oscillators
Peiyu Xia, Makoto Kuwata-Gonokami, Kosuke Yoshioka
Ultrashort pulses from Kerr-lens mode-locked oscillators have inspired a variety of applications. The design and alignment of these laser resonators have thus far been theoreticall…
Observation of ultra-high mobility excitons in a strain field by space- and time-resolved spectroscopy at sub-Kelvin temperatures
Yusuke Morita, Hirosuke Suzuki, Kosuke Yoshioka +1
We measured basic parameters such as the lifetime, mobility, and diffusion constant of trapped paraexcitons in cuprous oxide at very low temperatures (below 1 K) using a dilution r…
Dynamical Critical Behavior of an Attractive Bose-Einstein Condensate Phase Transition
Yiping Chen, Munekazu Horikoshi, Kosuke Yoshioka +1
When matter undergoes a continuous phase transition on a finite timescale, the Kibble-Zurek mechanism predicts universal scaling behavior with respect to structure formation. The s…
Direct Phase Locking of a Ti:Sapphire Optical Frequency Comb to a Remote Optical Frequency Standard
Eunmi Chae, Kota Nakashima, Takuya Ikeda +2
We report on an ultralow noise optical frequency transfer from a remotely located Sr optical lattice clock laser to a Ti:Sapphire optical frequency comb through telecom-wavelength…
The OVAL experiment: A new experiment to measure vacuum magnetic birefringence using high repetition pulsed magnets
Xing Fan, Shusei Kamioka, Toshiaki Inada +10
A new experiment to measure vacuum magnetic birefringence (VMB), the OVAL experiment, is reported. We developed an original pulsed magnet that has a high repetition rate and applie…
Study on Cooling of Positronium for Bose-Einstein Condensation
Kenji Shu, Xing Fan, Takayuki Yamazaki +4
A new method of cooling positronium down is proposed to realize Bose-Einstein condensation of positronium. We perform detail studies about three processes (1) thermalization proces…
Momentum-dependent sign-inversion of orbital polarization in superconducting FeSe
Y. Suzuki, T. Shimojima, T. Sonobe +14
We investigate the electronic reconstruction across the tetragonal-orthorhombic structural transition in FeSe by employing polarization-dependent angle-resolved photoemission spect…
Lifting of xz/yz orbital degeneracy at the structural transition in detwinned FeSe
T. Shimojima, Y. Suzuki, T. Sonobe +14
We study superconducting FeSe (Tc = 9 K) exhibiting the tetragonal-orthorhombic structural transition (Ts = 90 K) without any antiferromagnetic ordering, by utilizing angle-resolve…
Vectorial Control of Magnetization by Light
Natsuki Kanda, Takuya Higuchi, Hirokatsu Shimizu +2
Coherent light-matter interactions have recently extended their applications to the ultrafast control of magnetization in solids. An important but unrealized technique is the manip…
Transition to a Bose-Einstein condensate of excitons at sub-Kelvin temperatures
Kosuke Yoshioka, Eunmi Chae, Makoto Kuwata-Gonokami
Bose-Einstein condensation (BEC) is a quantum mechanical phenomenon directly linked to the quantum statistics of bosons. While cold atomic gases provide a new arena for exploring t…
Study of ortho-to-paraexciton conversion in CuO by excitonic Lyman spectroscopy
M. Kubouchi, K. Yoshioka, R. Shimano +2
Using time-resolved - excitonic Lyman spectroscopy, we study the orthoexciton-to-paraexcitons transfer, following the creation of a high density population of ultracold $1s…