SESSION 11: Quantum optics

Chair: (Steven van Enk (University of Oregon))
10:45am - 11:15amTiemo Landes, University of Oregon
Two-photon Fourier transform spectroscopy
Abstract. We detail the various quantum pathways and interferences in a Mach-Zehnder interferometer resulting from insertion of time-frequency entangled photon pairs (EPP) into a single port of the interferometer. We then experimentally demonstrate two-photon coincidence Fourier transform spectroscopy and refractometry using frequency degenerate EPP centered around 532 nm generated via Type-I collinear spontaneous parametric down-conversion. The measurement is further improved by introducing phase-modulation in the interferometer via acousto-optic modulators enabling phase-sensitive measurement referenced to a helium-neon laser counter-propagating through the interferometer. The phase-sensitive measurement reduces the sampling requirement in path-delay space to fully reproduce the interference fringes, as well as minimizing environmental noise and the effect of interferometer drift. We demonstrate the technique using a lock-in amplifier and a discrete time- and phase-tagging technique developed for low-flux measurements.
11:15am - 11:45amDileep Reddy, National Institute of Standards and Technology, Boulder; University of Colorado, Boulder
Micron-scale superconducting wires for polarization insensitive, near-unity efficiency single-photon detection
Abstract. Current-biased, superconducting-nanowire single-photon detectors are typically fabricated with wire-widths in the 100-200 nm range in order to ensure sensitivity to single-photon absorption at near-infrared energies. This has constrained the fill factors of nanowire meanders to conform to low values that limit current-crowding effects. It has also penalized large-area devices with large kinetic inductances and polarization-dependent efficiencies. Recent advances in silicon-rich WSi amorphous-superconducting film compositions have extended device sensitivities to mid-infrared photons. They have also enabled near-infrared sensitive devices with wire-widths in the 1-3 micron range, thus allowing for larger active areas with lower inductances, faster pulse-recovery times, and near-complete polarization independence. I will be presenting the design and measurement results for fiber-coupled superconducting microwire near-IR single-photon detectors that benefit from the aforementioned qualities, and boast system efficiencies exceeding 98%. I will also be presenting application extensions into imaging, and low-photon-number resolved detection.

SQuInT Chief Organizer
Akimasa Miyake, Associate Professor

SQuInT Co-Organizer
Brian Smith, Associate Professor UO

SQuInT Program Committee
Postdoctoral Fellows:
Markus Allgaier (UO OMQ)
Sayonee Ray (UNM CQuIC)
Pablo Poggi (UNM CQuIC)
Valerian Thiel (UO OMQ)

SQuInT Event Co-Organizers (Oregon)
Jorjie Arden
Holly Lynn

SQuInT Event Administrator (Oregon)
Brandy Todd

SQuInT Administrator (CQuIC)
Gloria Cordova
505 277-1850

SQuInT Founder
Ivan Deutsch, Regents' Professor, CQuIC Director

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