LIGO Quantum Schemes NSF Review, Oct. 2007

Quantum tricks in the coming decade Squeezed vacuum injection Radiation-pressure induced couplings of light with the mechanical oscillator Squeezed states of light Entangled states Squeezed states of mirror Quantum radiation pressure

Squeezed Input Interferometer Laser GW Detector SHG Faraday isolator The squeeze source drawn is an OPO squeezer, but it could be any other squeeze source, e.g. ponderomotive squeezer. OPO Homodyne Detector Squeeze Source GW Signal

Sub-quantum-limited interferometer Narrowband unsqueezed Broadband unsqueezed Broadband Squeezed X+ X- Quantum correlations Input squeezing

Squeezing injection experiment @ the 40m prototype @ Caltech Animated. (i) Experimental layout of 40m test; (ii) results Goda et al. (2007)

Squeeze injection in En/AdLIGO Here is a block diagram of what a practical squeezer for a post-S6 LIGO might look like. Sigg et al.

Radiation pressure effects Classical and quantum The curves that follow are all for the ponderomotive experiment  a FPMI with 1 gram end mirrors, 1 W of input power, arm cavity finesse of ~1e4. The same effects can exist in Advanced LIGO as well.

Classical radiation pressure effects Stiffer than diamond 6.9 mK Stable OS Radiation pressure dynamics Optical cooling

Quantum radiation pressure effects Entanglement Squeezing Mirror-light entanglement Squeezed vacuum generation