arXiv subjects

Toshiyuki Hosoya

Publications and source records attributed to Toshiyuki Hosoya.

6 recordsLinked to original sources

arXiv2026

Theoretical Proposal of a Digital Closed-Loop Thermal Atomic-Beam Interferometer for High-Bandwidth, Wide-Dynamic-Range, and Simultaneous Absolute Acceleration-Rotation Sensing

We present a theoretical proposal and simulation study of a digital closed-loop thermal atomic-beam interferometer for inertial navigation applications. The scheme synchronizes phase biasing with momentum-kick reversal through the atomic transit time, extracting four interferometric phases to suppress Raman beam path-length errors, while two-photon detuning feedback maintains a pseudo-inertial frame and eliminates cross-coupling. The interferometer enables simultaneous measurements of acceleration and rotation based on an absolute, atom-interferometric reference, with high bandwidth and a wide dynamic range. Numerical simulations verify that acceleration and angular velocity can be measured simultaneously and independently in real time without cross-coupling, demonstrating the absolute, decoupled nature of the proposed measurement scheme. We further evaluate the noise-limited performance of the sensor and obtain sensitivities of $3{\rm μm / s^2 / \sqrt{Hz}}$ (velocity random walk) and $15{\rm μdeg / \sqrt{h}}$ (angular random walk) for a ${170}^{\circ}$ $^{85}$Rb beam and an interferometer arm length of 100~mm, surpassing the performance of sensors currently used in state-of-the-art inertial navigation systems.

physics.atom-ph↗

arXiv2025

Sub-Recoil Transverse Momentum Width in a Cold Ytterbium Atomic Beam

We demonstrate the generation of a slow ytterbium atomic beam with a transverse momentum width of $0.44(6)$ times the photon recoil associated with Bragg diffraction, and a flux of $6.7(9) \times 10^6$ atoms/s. This is achieved by applying momentum filtering through a long-lived metastable state to atoms prepared in a slow beam via two-dimensional transverse laser cooling. The resulting narrow momentum distribution enables efficient quasi-Bragg diffraction, which we exploit to realize a Bragg interferometer. These results mark a significant step toward continuous, high-precision, and magnetically insensitive angular rate measurements using cold alkaline-earth(-like) atomic beams.

physics.atom-ph↗

arXiv2025

Closed-loop measurements in an atom interferometer gyroscope with velocity-dependent phase-dispersion compensation

Atom interferometer-based gyroscopes are expected to have a wide range of applications due to their high sensitivity. However, their dynamic range is limited by dephasing caused by velocity-dependent Sagnac phase shift in combination with the longitudinal velocity distribution of the atoms, restricting measurements of large angular velocities. In this study, we present a method for restoring the contrast deterioration in angular velocity measurements with interferometer gyroscopes using atomic beams. Our findings show that by introducing the pseudo-rotation effect with appropriate two-photon detunings for Raman lights in the interferometer, it is possible to effectively cancel the Sagnac phase shift for all atoms in the velocity distribution of the beam. Consequently, the contrast is unaffected by the rotation. Furthermore, we applied this method to an interferometer gyroscope with counter-propagating atomic beams sharing the same Raman lights. It is found that the angular velocity of the system can be estimated through the detuning point where the phase difference between the two interferometers is zero. This approach ensures that the scale factor of the atom interferometer gyroscope is independent of the change in the longitudinal velocity distribution of the atomic beam. We demonstrate our technique using the interferometer gyroscope of thermal atomic beams of rubidium-87, achieving a measurement of angular velocity of $\mathrm{{1.0}^{\circ}/s}$ even with an acceleration of 0.68$\mathrm{m/s^2}$ on a three-axis rotation table. This simple and robust dispersion compensation method with Raman light detuning benefits dynamic angular velocity measurements in field applications such as the inertial navigation of vehicles.

physics.atom-ph↗

arXiv2022

High-Flux Cold Ytterbium Atomic Beam Source Using Two-Dimensional Laser Cooling with Intercombination Transition

We demonstrate a high-flux and low transverse temperature atomic beam of ytterbium by applying two-dimensional cooling using the ${}^1\mathrm{S}_0\text{-}{}^3\mathrm{P}_1$ intercombination transition to the cold atomic beam produced by the dipolar-allowed ${}^1\mathrm{S}_0\text{-}{}^1\mathrm{P}_1$ transition. The optimized transverse temperature of $11 \pm 9\,\mathrm{μK}$ and an atomic flux of $(7.5 \pm 1.0) \times 10^8\,\mathrm{atoms/s}$ are obtained for the atomic beam whose longitudinal velocity is $30\,\mathrm{m/s}$. The transverse temperature is maintained below $23\,\mathrm{μK}$, while the flux is above $6.5 \times 10^8\,\mathrm{atoms/s}$ in the longitudinal velocity range of $22 - 30\,\mathrm{m/s}$. We also discuss the feasibility of further narrowing the transverse momentum width to less than the recoil momentum using the momentum-selective optical transition between the ground state and the long-lived metastable state. The transverse momentum width of our atomic beam, which is narrower than 5.7 times the recoil momentum, is a good starting point for the proposed method.

physics.atom-ph↗

arXiv2016

Measuring the branching ratios from the $y^8 {\rm P}_{9/2}$ state to metastable states in europium

We measure the branching ratios from the $y^8{\rm P}_{9/2}$ excited state to six metastable states of europium through fluorescence spectroscopy of an atomic beam. The sum of the six branching ratios is estimated to be $1.05(2)\times 10^{-3}$. This research provides us with insightful information to determine the feasibility of using the $a^8{\rm S}_{7/2} - y^8{\rm P}_{9/2}$ transition in order to implement the Zeeman slowing for europium atoms in the ground state. Based on this result, we also propose a scheme for Zeeman slowing and magneto-optical trapping, using a specific metastable state which has a cyclic transition.

cond-mat.quant-gas↗

arXiv2014

Injection locking of a high power ultraviolet laser diode for laser cooling of ytterbium atoms

We developed a high-power laser system at a wavelength of 399 nm for laser cooling of ytterbium atoms with ultraviolet laser diodes. The system is composed of an external cavity laser diode providing frequency stabilized output at a power of 40 mW and another laser diode for amplifying the laser power up to 220 mW by injection locking. The systematic method for optimization of our injection locking can also be applied to high power light sources at any other wavelengths. Our system, which does not depend on complex nonlinear frequency-doubling, has great importance for implementing transportable optical lattice clocks, and is also useful for investigations on condensed matter physics or quantum information processing using cold atoms.

physics.atom-ph↗