arXiv subjects

Martin Miranda

Publications and source records attributed to Martin Miranda.

7 recordsLinked to original sources

arXiv2025

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 $3{\rm \mu m / s^2 / \sqrt{Hz}}$ (velocity random walk) and $15{\rm \mu deg / \sqrt{h}}$ (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

Sensitivity Enhancement in Atom-Interferometer Gyroscopes via Phase-Modulation Signal Readout Scheme

Quantum sensors based on atom interferometers are advancing both fundamental physics and practical applications, with higher sensitivity being a key requirement for these investigations. Here, we experimentally demonstrate a sensitivity enhancement of an atom-interferometer gyroscope using a phase-modulation signal readout scheme. Phase modulation applied to the laser light used for atomic state manipulation is transferred to the atomic phase and read out via multi-harmonic demodulation. The observed sensitivity improvement factor of $1.20\pm0.04$ over the conventional phase sweep scheme agrees with theoretical predictions. We also found that phase-dispersion compensation control, which compensates atomic velocity dispersion and preserves interference contrast at high angular rates, effectively eliminates the nonlinearity inherent in multi-harmonic demodulation. The sensitivity improvement achieved by our method is applicable to a broad class of atom interferometers and requires no modifications to the optical or vacuum systems, making it particularly effective for size-constrained applications such as large-baseline experiments and inertial navigation systems.

physics.atom-ph↗

arXiv2024

Analyzing the sensitivity of an atom interferometer with a phase-modulation readout scheme

The sensitivity of an interferometer depends on its readout scheme. However, little attention has been paid to the readout schemes of atom interferometers from the viewpoint of their sensitivity. The difference in sensitivity between readout schemes or their optimization has not been considered in the literature. Herein we analytically calculate the sensitivities of an atom interferometer with typical readout schemes by applying the two-photon formalism, which was developed for optical interferometers to deal with quantum noise. Our calculations reveal that by using sinusoidal phase modulation, the sensitivity can surpass that obtained by the conventional phase sweeping scheme. The superiority of this phase modulation scheme for both cold and thermal atomic beams is demonstrated. In addition, we show that the phase modulation scheme is advantageous for atom-flux fluctuation and resists atom-flux drift. This study performs a general analysis of the sensitivity of atom interferometers and identifies an advantageous readout scheme.

physics.atom-ph↗

arXiv2022

Simultaneous Suppression of Thermal Phase Noise and Relative Intensity Noise in a Fiber Optic Gyroscope

The short-term sensitivity of a kilometer-long fiber-optic gyroscope is limited mainly by thermal phase noise and relative intensity noise. Increasing the phase modulation frequency decreases the thermal phase noise but not the relative intensity noise since it behaves as white noise. Here, we propose and experimentally demonstrate that the angular random walk can be effectively decreased by suppressing relative intensity noise at the modulation frequency and its third-order harmonic using direct feedback to the drive current of a superluminescent diode. Our simultaneous suppression of thermal phase noise and relative intensity noise yields an angular random walk of $15\,\mu\mathrm{deg}/\sqrt{\mathrm{h}}$ and a bias instability of $33\,\mu\mathrm{deg}/\mathrm{h}$ using a fiber coil with a length of $5\,$km and an effective area of $280\,\mathrm{m^2}$ for a measurement time of 40 hours.

physics.optics↗

arXiv2017

Site-resolved imaging of a bosonic Mott insulator using ytterbium atoms

We demonstrate site-resolved imaging of a strongly correlated quantum system without relying on laser-cooling techniques during fluorescence imaging. We observed the formation of Mott shells in the insulating regime and realized thermometry on the atomic cloud. This work proves the feasibility of the noncooled approach and opens the door to extending the detection technology to new atomic species.

cond-mat.quant-gas↗

arXiv2015

Site-resolved imaging of ytterbium atoms in a two-dimensional optical lattice

We report a high-resolution microscope system for imaging ultracold ytterbium atoms trapped in a two-dimensional optical lattice. By using the ultraviolet strong transition combined with a solid immersion lens and high-resolution optics, our system resolved individual sites in an optical lattice with a 544-nm spacing. Without any cooling mechanism during the imaging process, the deep potential required to contain the atoms was realized using a combination of a shallow ground-state and a deep excited-state potentials. The lifetime and limitations of this setup were studied in detail.

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↗