Interferometric Imaging Using Shared Quantum Entanglement.

Quantum entanglement-based imaging promises significantly increased resolution by extending the spatial separation of optical collection apertures used in very-long-baseline interferometry for astronomy and geodesy. We report a tabletop entanglement-based interferometric imaging technique that utilizes two entangled field modes serving as a phase reference between two apertures. The spatial distribution of a simulated thermal light source is determined by interfering light collected at each aperture with one of the entangled fields and performing joint measurements.

Smartphone-based measurements of the optical properties of snow.

Snow is a highly complex medium composed of ice crystals of various shapes and sizes. Knowledge of its intrinsic optical properties such as scattering and absorption coefficients is tantamount to radiative transfer models in climate research. The absorption coefficient, in particular, allows us to access information about light-absorbing particles contained in the snow.

Quantifying the enhancement of two-photon absorption due to spectral-temporal entanglement.

When a low flux of time-frequency-entangled photon pairs (EPP) illuminates a two-photon transition, the rate of two-photon absorption (TPA) can be enhanced considerably by the quantum nature of photon number correlations and frequency correlations. We use a quantum-theoretic derivation of entangled TPA (ETPA) and calculate an upper bound on the amount of quantum enhancement that is possible in such systems. The derived bounds indicate that in order to observe ETPA the experiments would need to operate at a combination of significantly higher rates of EPP illumination, molecular concentrations, and conventional TPA cross sections than are achieved in typical experiments.

Diffuse optics for glaciology.

Optical probing of glaciers has the potential for tremendous impact on environmental science. However, glacier ice is turbid, which prohibits the use of most established optical measurements for determining a glacier's interior structure. Here, we propose a method for determining the depth, scattering and absorption length based upon diffuse propagation of short optical pulses.

Temporal mode transformations by sequential time and frequency phase modulation for applications in quantum information science.

Controlling the temporal mode shape of quantum light pulses has wide ranging application to quantum information science and technology. Techniques have been developed to control the bandwidth, allow shifting in the time and frequency domains, and perform mode-selective beam-splitter-like transformations. However, there is no present scheme to perform targeted multimode unitary transformations on temporal modes.

Tomography and Purification of the Temporal-Mode Structure of Quantum Light.

High-dimensional quantum information processing promises capabilities beyond the current state of the art, but addressing individual information-carrying modes presents a significant experimental challenge. Here we demonstrate effective high-dimensional operations in the time-frequency domain of nonclassical light. We generate heralded photons with tailored temporal-mode structures through the pulse shaping of a broadband parametric down-conversion pump.

Highly efficient frequency conversion with bandwidth compression of quantum light.

Hybrid quantum networks rely on efficient interfacing of dissimilar quantum nodes, as elements based on parametric downconversion sources, quantum dots, colour centres or atoms are fundamentally different in their frequencies and bandwidths. Although pulse manipulation has been demonstrated in very different systems, to date no interface exists that provides both an efficient bandwidth compression and a substantial frequency translation at the same time. Here we demonstrate an engineered sum-frequency-conversion process in lithium niobate that achieves both goals.

Spectral properties of microwave graphs with local absorption.

The influence of absorption on the spectra of microwave graphs has been studied experimentally. The microwave networks were made up of coaxial cables and T junctions. First, absorption was introduced by attaching a 50Ω load to an additional vertex for graphs with and without time-reversal symmetry.