Kai Shinbrough

University of Illinois, Urbana-Champaign | UIUC · Department of Physics

We present a demonstration of simultaneous high-efficiency, high-speed, and low-noise operation of a photonic quantum memory. By leveraging controllable collisional dephasing in a neutral barium atomic vapor, we demonstrate a significant improvement in memory efficiency and bandwidth over existing techniques. We achieve greater than 95% storage eff...

The storage and retrieval of photonic quantum states, quantum memory, is a key resource for a wide range of quantum applications. Here we investigate the sensitivity of Λ-type quantum memory to experimental fluctuations and drift. We use a variance-based approach, focusing on the effects of fluctuations and drift on memory efficiency. We consider s...

Broadband quantum memory is critical to enabling the operation of emerging photonic quantum technology at high speeds. Here we review a central challenge to achieving broadband quantum memory in atomic ensembles -- what we call the 'linewidth-bandwidth mismatch' problem -- and the relative merits of various memory protocols and hardware used for ac...

We measure 95.6±0.3% storage efficiency of ultrafast photons in a collisionally broadened barium vapor quantum memory. We measure 31±1% total efficiency, limited by control field power, and a 0.515(6) ns lifetime, limited by motional dephasing.

The storage and retrieval of photonic quantum states, quantum memory, is a key resource for a wide range of quantum applications. Here we investigate the sensitivity of $\Lambda$-type quantum memory to experimental fluctuations and drift. We use a variance-based approach, focusing on the effects of fluctuations and drift on memory efficiency. We co...

We examine the sensitivity of Λ-type optical quantum memories to experimental fluctuations using a variance-based analysis. The results agree with physical interpretations of quantum memory protocols, and are important for practical implementations.

We report record storage efficiencies in the first atomic THz-bandwidth quantum memory. Near-off-resonant orbital transitions in collisionally broadened hot atomic barium vapor allow for 83% storage efficiency, 25% total efficiency, and a time-bandwidth-product of 800.

Optical quantum memory, the ability to store photonic quantum states and retrieve them on demand, is an essential resource for emerging quantum technologies and photonic quantum information protocols. Simultaneously achieving high efficiency and high-speed, broadband operation is an important task necessary for enabling these applications. We inves...

We optimize the efficiency of broadband Λ-type quantum memories under the restriction of Gaussian-shape optical fields. We demonstrate an experimentally-simple path to enhancing memory efficiency over a wide range of broadband memory parameters.

Optical quantum memory--the ability to store photonic quantum states and retrieve them on demand--is an essential resource for emerging quantum technologies and photonic quantum information protocols. Simultaneously achieving high efficiency and high-speed, broadband operation is an important task necessary for enabling these applications. In this...

We develop a Hamiltonian formalism to study energy and position (momentum) correlations between a single Stokes photon and a single material excitation that are created as a pair in the spontaneous Raman scattering process. Our approach allows for intuitive separation of the effects of spectral linewidth, chromatic dispersion, and collection angle...

We optimize Λ-type ensemble quantum memories under the restriction of Gaussian optical fields, with particular focus on the Autler-Townes-splitting regime. We find significant enhancement of efficiency and provide an interpretation of the underlying physics.

We develop a Hamiltonian formalism to study energy and position/momentum correlations between a single Stokes photon and a single material excitation that are created as a pair in the spontaneous Raman scattering process. Our approach allows for intuitive separation of the effects of spectral linewidth, chromatic dispersion, and collection angle on...

We experimentally study the generation of photon pairs via spontaneous four-wave mixing with two distinct laser pulses. We find that the dual-pump technique enables new capabilities: 1) a new characterization methodology to measure noise contributions, source brightness and photon-collection efficiencies directly from raw photon-count measurements;...

We experimentally study the generation of photon pairs via spontaneous four-wave mixing with two distinct laser pulses. We find that the dual-pump technique enables new capabilities: 1) a new characterization methodology to measure noise contributions, source brightness and photon collection efficiencies directly from raw photon-count measurements;...

We present 1D and 3D models that take into account Stokes-photon–excitation pair correlations in Raman scattering, revealing nontrivial dependence of the photon statistics on linewidth, dispersion and collection angle.

We experimentally demonstrate a dual-pump spontaneous four-wave mixing photon-pair source for which we quantify the noise to determine the generation probability and collection efficiency directly, and that generates photons in pure quantum states.

Hydrogen isotope separation based on difference in quantum zero-point energy is investigated using a novel temperature-programmed desorption approach. Spectra obtained as a function of hydrogen concentration reveal multiple distinct binding sites that correlate with the crystallographic structure of the particular material. In each case the higher...

Towards delayed-choice generation of single photons in pure quantum states, we measure and model the purity of Stokes photons scattered from sapphire, measuring a maximum purity of 0.99±0.03 and high quantum correlation with anti-Stokes photons.

We experimentally tailor the joint spectra of photon pairs produced via dual-pump spontaneous four-wave mixing, achieving a joint spectral intensity without side-lobes. This work presents a new route towards generating spectrally uncorrelated photon pairs.

We measure the quantum-state purity of Raman-scattered photons from sapphire, achieving a purity of 1.00 ± 0.03 and quantitative agreement with a new theoretical model of photon-phonon correlations that includes dispersion and finite excitation lifetime.

Infrared spectroscopy is used to observe the orientational fine structure arising from ortho-H2 adsorbed at the primary site of the microporous framework MOF-5. The Q1(1) vibrational transition shows at least two symmetrically spaced fine structure bands on either side of the main band. These grow in relative intensity with increasing H2 concentrat...