Środowiskowe Seminarium z Informacji i Technologii Kwantowych

A longstanding goal in quantum optics has been to realize a photon-number-resolvingdetector that efficiently counts the number of photons in a field. This goalhas been largely met with the development of transition edge sensors which cancount up to roughly 15 photons with efficiencies over 95% [1]. In this talk, I will present experimental work employing these detectors for characterizing and engineering quantum states of light. In a first experiment, we build a “weak-field homodyne” detector by replacing the photodiodes conventionally used in homodyne detection with transition edge sensors. We show that this detector can tune between photon-number and quadrature measurements by changing the strength of the local oscillator [2]. This tunability enables the detector to project light onto a wide range of states, including superpositions of coherent states, i.e. optical Schrödinger cat states. In a second experiment, we use transition edge sensors and high-gain parametric down-conversion sources to prepare and detect large Fock states for quantum-enhanced interferometry [3].

[1] Opt. Exp. 16 3032-3040 (2008)
[2] Phys. Rev. A 101 031801(R) (2020)
[3] npj Quantum Inf. 6 89 (2020)

ZOOM link: https://zoom.us/j/6526721604?pwd=Y0pPdE9vT1hNWWNiZVBMaEVOeHN2dz09