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Prof. Avi Pe'er - "Lifting the Bandwidth Limit of Optical Homodyne Measurement"

Physics Department and BINA Center for Nanotechnology Bar Ilan University, Ramat Gan, Israel

Max Planck Institute for the Science of Light
Gerd Leuchs

Time, place:
Monday, August 22, 2016, 11 a.m.
Large seminar room (429/435), Bau 24, Guenther-Scharowsky-Str. 1

Homodyne measurement is a corner-stone of quantum optics. It is the major method for measuring the quadratures of light - the quantum optical analog of position and momentum. The standard homodyne detection suffers from an inherent bandwidth limitation due to the square-law photo-detectors that are used as the nonlinear field multipliers, limiting the detection bandwidth to the electronically accessible GHz range at most. Thus, the study and application of squeezed light is limited primarily to (near) degenerate squeezing, almost neglecting the general two-mode and broadband squeezing, which are very easily produced, but requires much larger optical bandwidth for homodyne measurement. I will present a direct optical homodyne technique with practically unlimited bandwidth, utilizing optical parametric amplification as the nonlinear multiplier. Using four-wave mixing parametric amplification in a photonic crystal fiber we demonstrate a simultaneous optical homodyne measurement of broadband two-mode squeezed light across 55THz of spectral bandwidth with a frequency separation of ~90THz between the two mode centers. I will describe semi-classical intuition for use of optical nonlinearity in homodyne measurements, along with a full quantum treatment of the measurement scheme.