Squeezing a Rainbow from Vacuum and Measuring it
Squeezed states of light are a major quantum resource in quantum optics. Their unique non-classical correlations (photon-number correlation and phase anti-correlation beyond the shot-noise limit) are a key to many quantum information applications, such as continuous variable quantum computing, quantum communication and key-distribution, teleportation, and sub-shot-noise interferometry.
Quadrature squeezing or squeezed light can span a full bandwidth of pair frequency modes that contribute together to the collective quadratures of the squeezed oscillation. The frequency separation between the modes of a pair can be anywhere between zero (degenerate squeezing) to an optical octave, and the number of simultaneous pairs is generally unlimited (an octave-spanning spectrum was demonstrated). In most experiments however, only the very special case of (nearly) degenerate squeezing is used, or just a single pair. While broad bandwidth is a welcomed resource in many other fields, the use of squeezed states is limited to narrow, almost DC, bandwidth. This is primarily due to the inherently limited bandwidth of optical homodyne measurement, which is the major tool to measure and manipulate squeezed states, and to the incompatibility of standard mode locking methods to parametric oscillators, which are the major tool for generating strong squeezing.
In this talk I will present both a new homodyne measurement and a new generation scheme suitable for ultra-broadband squeezing; I will present a novel homodyne method for measuring optical bandwidth squeezing, demonstrating a measurement of more than 3dB squeezing over ~50THz bandwidth. And I will present an intriguing new method for active mode-locking in a parametric oscillator, allowing the generation of broadband strongly squeezed light.