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Generation of a stable low-frequency squeezed vacuum field with periodically-poled KTiOPO$_4$ at 1064 nm

Keisuke Goda·Eugeniy E. Mikhailov·Osamu Miyakawa·Shailendhar Saraf·Stephen Vass·Alan Weinstein·Nergis Mavalvala
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Abstract

We report on the generation of a stable continuous-wave low-frequency squeezed vacuum field with a squeezing level of $3.8\pm0.1$ dB at 1064 nm, the wavelength at which laser interferometers for gravitational wave (GW) detection operate, using periodically poled KTiOPO$_4$ (PPKTP) in a sub-threshold optical parametric oscillator. PPKTP has the advantages of higher nonlinearity, smaller intra-crystal and pump-induced seed absorption, user-specified parametric down-conversion temperature, wider temperature tuning range, and lower susceptibility to thermal lensing over alternative nonlinear materials such as MgO doped or periodically poled LiNbO$_3$, and is, therefore, an excellent material for generation of squeezed vacuum fields for application to laser interferometers for GW detection.

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Keisuke Goda, Eugeniy E. Mikhailov, Osamu Miyakawa, Shailendhar Saraf, Stephen Vass, Alan Weinstein, Nergis Mavalvala. 2007-02-28. Generation of a stable low-frequency squeezed vacuum field with periodically-poled KTiOPO$_4$ at 1064 nm. https://doi.org/10.1364/ol.33.000092

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