Squashed States of Light: Theory and Applications to Quantum Spectroscopy

Abstract

Using a feedback loop it is possible to reduce the fluctuations in one quadrature of an in-loop field without increasing the fluctuations in the other. This effect has been known for a long time, and has recently been called ``squashing'' [B.C. Buchler et al., Optics Letters {\bf 24}, 259 (1999)], as opposed to the ``squeezing'' of a free field in which the conjugate fluctuations are increased. In this paper I present a general theory of squashing, including simultaneous squashing of both quadratures and simultaneous squeezing and squashing. I show that a two-level atom coupled to the in-loop light feels the effect of the fluctuations as calculated by the theory. In the ideal limit of light squeezed in one quadrature and squashed in the other, the atomic decay can be completely suppressed.

8 pages plus one figure. Submitted to JEOS-B for Dan Walls Special Issue

References in corpus (3)

• All-optical versus electro-optical quantum-limited feedback
• In-loop squeezing is real squeezing to an in-loop atom
• Suppression of Classical and Quantum Radiation Pressure Noise via Electro-Optic Feedback

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• On the optimal feedback control of linear quantum systems in the presence of thermal noise
• Cavity optomechanics with feedback--controlled in--loop light
• Enhancement of three-mode optomechanical interaction by feedback-controlled light
• Dissipative Quantum Feedback in Measurements Using a Parametrically Coupled Microcavity
• Quantum noise and its evasion in feedback oscillators
• Effects of twin-beam squashed light on a three-level atom
• Motional Squashed States
• A room temperature optomechanical squeezer
• Causal State Estimation and the Heisenberg Uncertainty Principle
• Symmetry and Topology of Successive Quantum Feedback Control
• Effect of biased noise fluctuations on the output radiation of coherent beat laser