Lectures on Quantum Optics and Quantum Information
Lectures on Quantum Optics and Quantum Information
Lectures on Quantum Optics and Quantum Information
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Effect of Losses <strong>on</strong> Squeezed Light<br />
Model of losses in quantum optics<br />
Intensity loss : 1-<br />
Can be modelled by a beam<br />
splitter with reflectivity R=1<strong>and</strong><br />
transmitivity T= .<br />
Vacuum fluctuati<strong>on</strong>s are<br />
entering by the empty port.<br />
Calculati<strong>on</strong>s<br />
• We linearize the fluctuati<strong>on</strong>s :<br />
<strong>and</strong> obtain for a quadrature P:<br />
• We calculate the noise variance :<br />
=V’<br />
• The beam-splitter gives:<br />
=V<br />
=1 (shot)<br />
What is<br />
the noise<br />
after the<br />
loss?<br />
<strong>and</strong><br />
V’ goes to 1 (shot) for str<strong>on</strong>g losses ( =0), ok!<br />
Some illlustrative values…..<br />
V=0.1 (10dB squeezing)<br />
10% loss give:<br />
V’=0.2 (7dB squeezing)<br />
Squeezing is very<br />
sensitive to losses!<br />
=0 (uncorrelated)
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