Real-time shot-noise-limited differential photodetection for atomic quantum control

A Compact Microchip-Based Atomic Clock Based on Ultracold Trapped Rb Atoms

We propose a compact atomic clock based on ultracold Rb atoms that are magnetically trapped near the surface of an atom microchip. An interrogation scheme that combines electromagnetically-induced transparency (EIT) with Ramsey's method of separated oscillatory fields can achieve atomic shot-noise level performance of 10^{-13}/sqrt(tau) for 10^6 atoms. The EIT signal can be detected with a heterodyne technique that provides noiseless gain; with this technique the optical phase shift of a 100 pW probe beam can be detected at the photon shot-noise level. Numerical calculations of the density mat…

利用光子相关性的折射率传感量子等离子体模型

Quantum plasmonics model of refractive index sensing using photon correlations

本文提出一种由量子发射体和金属纳米颗粒组成的纳米传感器系统，利用高阶光子相关性进行折射率传感，发现在特定条件下可将噪声降至散粒噪声极限以下，实现传感性能的量子增强。

Imaging moving atoms by holographically reconstructing the dragged slow light

The propagation of light in moving media is dragged by atomic motion. The light-drag effect can be dramatically enhanced by reducing the group velocity with electro-magnetically induced transparency (EIT). We develop a systematic procedure to accurately reconstruct the complex wavefront of the slow light with single-shot measurements, enabling precise, photon shot-noise limited spectroscopic measurements of atomic response across EIT even in presence of generic atomic number fluctuations. Applying the technique to an expanding cloud of cold atoms, we demonstrate simultaneous inference of the a…

Quantum limit of hybrid atom-mechanical gyroscope based on electro-magnetically induced transparency

Application of hybrid atom-mechanical oscillator for absolute rotation detection is studied. The hybrid atom-mechanical oscillator consists of an atomic cell, filled with three level atoms, which is fixed on a mechanical oscillator. The atom-mechanical oscillator is placed on a rotating table such that the Coriolis force moves the atomic cell with respect to the incoming laser field. Thus the atomic resonance frequencies are Doppler shifted, and the phase of the laser field interacting with the atomic medium changes. Absolute rotation parameters are estimated by measuring the phase change in t…

基于原子模型训练自编码器的单次相干衍射图样亚光子精度降噪

Sub-photon accuracy noise reduction of single shot coherent diffraction pattern with atomic model trained autoencoder

本研究利用自编码器对单次相干衍射图样进行亚光子精度降噪，U-net表现最佳，并成功应用于不同形状粒子的成像，凸显迁移学习价值。

Imaging cold atoms with shot-noise and diffraction limited holography

We theoretically develop and experimentally demonstrate a holographic method for imaging cold atoms at the diffraction and photon shot noise limits. Aided by a double point source reference field, a simple iterative algorithm robustly removes the twin image of an $^{87}$Rb cold atom sample during the image reconstruction. Shot-noise limited phase shift and absorption images are consistently retrieved at various probe detunings, and during the laser cooling process. We consistently resolve less than 2 mrad phase shift ($0.4~\%$ attenuation) of the probe light, outperforming shot-noise limited p…

使用高分辨率波长计实现散粒噪声限制的激光频率稳定

Shot-Noise-Limited Laser Frequency Stabilization Using a High-Resolution Wavelength Meter

提出一种将556 nm激光锁定于高精度波长计的紧凑型频率稳定方法，通过闭环反馈抑制长期漂移，在无需复杂光学组件下实现低于百千赫兹的散粒噪声限制稳定性，适用于现场部署及精密光学实验。

Single-shot framing integration photography with high spatial resolution at 5.3*1012 frames per second by an inversed 4f system

We present a framing integration ultrafast photography (FIP), which integrates the framing structure, codes a dynamic event by an inversed 4f system (I4F) and decodes regionally with high spatial resolution. In the experiment about laser-induced plasma, FIP achieved a framing rate of 5.3*1012 frames per second (fps) and an intrinsic spatial resolution of 110.4 lp/mm. It has an excellent spatio-temporal resolution and a compact and flexible structure. Hence, it can probe unrepeatable ultrafast intra- and inter-atomic/molecular dynamics, different in size and duration with high-quality. Besides,…