arXiv subjects

Hansol Jeong

Publications and source records attributed to Hansol Jeong.

4 recordsLinked to original sources

arXiv2026

Photon shot-noise-limited Rydberg-EIT electrometry

Rydberg-atom electrometry is a core technique in the development of highly sensitive quantum electric-field sensors. Its sensitivity based on atom-photon interaction is typically limited by photon shot-noise (PSN) and spectral broadenings. Here, we experimentally demonstrate a near PSN-limited Rydberg electrometry from a 85Rb atomic vapor cell. By engineering atomic coherence through control of residual magnetic fields and laser frequency noise, we achieve the Rydberg electromagnetically induced transparency (EIT) with the narrow linewidth of 1.6 MHz, yielding an enhanced spectral slope for high-sensitivity Rydberg-EIT electrometry. Under optimized superheterodyne detection conditions, we obtain an electric-field sensitivity of 12.5(8) nV cm^-1 Hz^-1/2 at 37 GHz, in close agreement with the calculated PSN limit. These results provide direct experimental evidence of the high-sensitive quantum electrometry and establish a practical route toward quantum-noise-limited Rydberg electrometry.

physics.atom-ph↗

arXiv2026

Atomic-referenced Hz-linewidth lasers via fiber interferometric stabilization

Narrow-linewidth lasers with absolute frequency anchoring are essential for precision metrology, coherent sensing, and emerging quantum technologies beyond laboratory environments. Optical cavities and interferometers provide exceptional short-term spectral purity but lack intrinsic absolute frequency references. Atomic transitions, in contrast, provide stable frequency anchors but offer limited discrimination sensitivity. Recent hybrid approaches have demonstrated the combination of compact optical resonators with atomic references, yet achieving the Hz-level regime remains challenging. Here, we present a hybrid architecture that enables simultaneous realization of Hz-level linewidth and atomic-referenced frequency stability. An external-cavity diode laser is first stabilized to a fiber interferometer to achieve Hz-level spectral purity, while the interferometer is subsequently anchored to an 87Rb D2 transition via modulation transfer spectroscopy to suppress long-term drift and define the laser frequency relative to the atomic transition. This dual-stabilization scheme realizes a compact atomic-referenced laser with a 3.4-Hz linewidth (1-rad integrated-phase method), a minimum fractional frequency stability of 3.4x10-14 at 0.56 s, and 9x10-13 at 100 s. This architecture establishes a practical and scalable route toward compact and field-deployable atomic-referenced narrow-linewidth lasers for precision metrology and quantum technologies.

physics.optics↗

arXiv2025

Real-Field Hong-Ou-Mandel Interference of Indistinguishable Coherent Photons via Long Optical Injection-Locking over 50 km Fiber

Measurement-device-independent quantum key distribution (MDI-QKD) has garnered significant attention for its potential to enable security-loophole-free quantum communication. Successful MDI-QKD protocols rely on performing a two-photon Bell-state measurement at an intermediate node, with a high-visibility Hong-Ou-Mandel (HOM) interference pattern between two independent coherent photons being crucial. In this study, we present a novel approach for developing indistinguishable coherent photon sources over 50 km of optical fiber in a real-world setting. We introduce the long optical injection-locking (long-OIL) technique, which enables frequency locking between two long-distance coherent photons beyond the coherence length of the master laser. Using the long-OIL technique, we achieved time-resolved HOM interference with a visibility of 48(2)%, approaching the theoretical 50% limit for two independent continuous-wave coherent photons. Our results demonstrate that the long-OIL platform is a promising solution for MDI-QKD with repeaterless secret key capacity.

quant-ph↗

arXiv2024

Collective biphoton temporal waveform of photon-pair generated from Doppler-broadened atomic ensemble

Photonic quantum states generated from atomic ensembles will play important roles in future quantum networks and long-distance quantum communication because their advantages, such as universal identity and narrow spectral bandwidth, are essential for quantum nodes and quantum repeaters based on atomic ensembles. In this study of the biphoton temporal waveform (BTW) of the photon pairs generated from a cascade-type two-photon-transition, we report the collectively coherent superposition of biphoton wavefunction emitted from different velocity classes in a Doppler-broadened cascade-type atomic ensemble. We experimentally demonstrate that the three times difference of temporal width of both BTWs varies dependent on the wavelengths of the signal and idler photons from both 6S_{1/2}-6P_{3/2}-6D_{5/2} and -8S_{1/2} transitions of Cs, corresponding to the idler and signal wavelengths of 852 nm-917 nm and 852 nm-795 nm, respectively. Our results help understand the characteristics of biphoton sources from a warm atomic ensemble and can be applied to long-distance quantum networks and practical quantum repeaters based on atom-photon interactions.

quant-ph↗