Aberration cancellation in quantum interferometry

Nonlocal cancellation of dispersion in Franson interferometry

Dispersion and its cancellation in entanglement-based nonlocal quantum measurements are of fundamental and practical interests. We report the first demonstration of cancellation of femtosecond-level dispersion by inverting the sign of the differential dispersion between the long and short paths in only one arm of a fiber-based Franson interferometer. We restore the otherwise limited quantum visibility to an unprecedented 99.6%, and put time-energy entanglement at the same level of quality as polarization entanglement for use in quantum information processing applications.

Classical Realization of Dispersion Cancellation by Time-Reversal Method

We propose a classical optical interferometry scheme that reproduces dispersion-insensitive Hong-Ou-Mandel interferograms. The interferometric scheme is derived from a systematic method based on the time-reversal symmetry of quantum mechanics. The scheme uses a time-reversed version of a Hong-Ou-Mandel interferometer with pairs of orthogonally polarized input laser pulses. We experimentally demonstrate automatic dispersion cancellation using the interferometry. The results show that the interferometer can obtain high-visibility interferograms with high signal conversion efficiency.

Nonclassical Nature of Dispersion Cancellation and Nonlocal Interferometry

Several recent papers have shown that some forms of dispersion cancellation have classical analogs and that some aspects of nonlocal two-photon interferometry are consistent with local realistic models. It is noted here that the classical analogs only apply to local dispersion cancellation experiments [A.M. Steinberg et al., Phys. Rev. Lett. 68, 2421 (1992)] and that nonlocal dispersion cancellation [J.D. Franson, Phys. Rev. A 45, 3126 (1992)] is inconsistent with any classical field theory and has no classical analog. The local models that have been suggested for two-photon interferometry are…

Multiparameter entangled state engineering using adaptive optics

We investigate how quantum coincidence interferometry is affected by a controllable manipulation of transverse wave-vectors in type-II parametric down conversion using adaptive optics techniques. In particular, we discuss the possibility of spatial walk-off compensation in quantum interferometry and a new effect of even-order spatial aberration cancellation.

Interacting quantum mixtures for precision atom interferometry

We present a source engineering concept for a binary quantum mixture suitable as input for differential, precision atom interferometry with drift times of several seconds. To solve the non-linear dynamics of the mixture, we develop a set of scaling approach equations and verify their validity contrasting it to the one of a system of coupled Gross-Pitaevskii equations. This scaling approach is a generalization of the standard approach commonly used for single species. Its validity range is discussed with respect to intra- and inter-species interaction regimes. We propose a multi-stage, non-line…

Quantum-inspired interferometry with chirped laser pulses

We introduce and implement an interferometric technique based on chirped femtosecond laser pulses and nonlinear optics. The interference manifests as a high-visibility (> 85%) phase-insensitive dip in the intensity of an optical beam when the two interferometer arms are equal to within the coherence length of the light. This signature is unique in classical interferometry, but is a direct analogue to Hong-Ou-Mandel quantum interference. Our technique exhibits all the metrological advantages of the quantum interferometer, but with signals at least 10^7 times greater. In particular we demonstrat…

Determination of spatial quantum states by using Point Diffraction Interferometry

We present a method to reconstruct pure spatial qudits of arbitrary dimension $d$, which is based on a point diffraction interferometer. In the proposed scheme, the quantum states are codified in the discretized transverse position of a photon field, once they are sent through an aperture with $d$ slits, and a known background is added to provide a phase reference. To characterize these photonic quantum states, the complete phase wavefront is reconstructed through a phase-shifting technique. Combined with a multipixel detector, the acquisition can be parallelized, and only four interferograms …

用于光纤量子网络的非局域弗朗索干涉仪的被动同步

Passive Synchronization of Nonlocal Franson Interferometry for Fiber-Based Quantum Networks Using Co-propagating Classical Clock Signals

本研究通过在光纤中同时传播经典时钟信号和量子纠缠光子对，实现了非局域量子干涉的高可见度和皮秒级被动同步，为光纤量子网络提供了实用的同步方案。

主成分分析用于原子干涉测量中的空间相位重建

Principal Component Analysis for Spatial Phase Reconstruction in Atom Interferometry

本文提出基于 Principal Component Analysis 的无模型方法，从图像集中重建原子干涉仪空间相位与逐图偏移，并通过模拟标度律和原子重力仪数据验证其有效性。

利用Hong-Ou-Mandel干涉测量法以极限精度快速测量群折射率变化

Fast measurement of group index variation with ultimate precision using Hong-Ou-Mandel interferometry

针对基于HOM干涉测量法的光延迟测量耗时问题，通过优化光子对生成用1毫米PPKTP晶体长度，实现每厘米样品长度约6.75×10⁻⁶的群折射率测量精度（较此前提升超400%），并验证了200℃范围内PPKTP群折射率变化的百万分之一精度测量。