41 research outputs found
Probing Ultra-Fast Dephasing via Entangled Photon Pairs
We demonstrate how the Hong-Ou-Mandel (HOM) interference with
polarization-entangled photons can be used to probe ultrafast dephasing. We can
infer the optical properties like the real and imaginary parts of the complex
susceptibility of the medium from changes in the position and the shape of the
HOM dip. From the shift of the HOM dip, we are able to measure 22 fs dephasing
time using a continuous-wave (CW) laser even with optical loss > 97%, while the
HOM dip visibility is maintained at 92.3~\% (which can be as high as 96.7%).
The experimental observations, which are explained in terms of a rigorous
theoretical model, demonstrate the utility of HOM interference in probing
ultrafast dephasing.Comment: 12 pages, 7 figure
Enhanced Cerenkov Second-Harmonic Generation in Patterned Lithium Niobate
We present experimental results of second harmonic generation enhancement through the resonance of the band edge in a photonic crystal based on lithium niobate. Proton exchange technique was used to fabricate a waveguide near the surface of the lithium niobate substrate. The photonic crystal structure over the waveguide was made by UV laser interferometry. Subsequently experiments were designed to quantify the Cerenkov second-harmonic generation (CSHG) radiated into the substrate. The SHG radiated inside the waveguides was also experimentally investigated. In our experiments, the second guided mode of the waveguide was tuned to the band edge resonance to enhance the second harmonic generation. The highest conversion efficiency of CSHG using photonic band gap (PBG) was around 50 times compared to SHG emission from non-patterned lithium niobate. A numerical model was used to corroborate the experimental result. It was also found that the SHG signal in the waveguides is quenched compared to the CSHG signal
Ultralow-power local laser control of the dimer density in alkali-metal vapors through photodesorption
Ultralow-power diode-laser radiation is employed to induce photodesorption of
cesium from a partially transparent thin-film cesium adsorbate on a solid
surface. Using resonant Raman spectroscopy, we demonstrate that this
photodesorption process enables an accurate local optical control of the
density of dimer molecules in alkali-metal vapors.Comment: 4 pages, 4 figure
2022 Roadmap on integrated quantum photonics
AbstractIntegrated photonics will play a key role in quantum systems as they grow from few-qubit prototypes to tens of thousands of qubits. The underlying optical quantum technologies can only be realized through the integration of these components onto quantum photonic integrated circuits (QPICs) with accompanying electronics. In the last decade, remarkable advances in quantum photonic integration have enabled table-top experiments to be scaled down to prototype chips with improvements in efficiency, robustness, and key performance metrics. These advances have enabled integrated quantum photonic technologies combining up to 650 optical and electrical components onto a single chip that are capable of programmable quantum information processing, chip-to-chip networking, hybrid quantum system integration, and high-speed communications. In this roadmap article, we highlight the status, current and future challenges, and emerging technologies in several key research areas in integrated quantum photonics, including photonic platforms, quantum and classical light sources, quantum frequency conversion, integrated detectors, and applications in computing, communications, and sensing. With advances in materials, photonic design architectures, fabrication and integration processes, packaging, and testing and benchmarking, in the next decade we can expect a transition from single- and few-function prototypes to large-scale integration of multi-functional and reconfigurable devices that will have a transformative impact on quantum information science and engineering