Heidelberg 2015 – wissenschaftliches Programm
A 19.3: Vortrag
Mittwoch, 25. März 2015, 11:30–11:45, C/HSO
Utilizing weak pump depletion to stabilize squeezed vacuum states — •Timo Denker1, Maximilian H. Wimmer1, Dirk Schütte1, Trevor A. Wheatley2, Elanor Huntington3, and Michèle Heurs1 — 1Albert-Einstein-Institut (Max-Planck-Institut für Gravitationsphysik), Hannover, Deutschland — 2The University of New South Wales, Canberra, Australia — 3The Australian National University, Canberra, Australia
We propose and demonstrate a pump-phase locking technique that makes use of weak pump depletion (WPD) – an unavoidable effect that is usually neglected – in a sub-threshold optical parametric oscillator (OPO). We show that the phase difference between seed and pump field is imprinted on pump and seed light by the non-linear interaction in the crystal and can be read out without disturbing the squeezed output. In our experimental setup the input of the OPO is 0.55 mW of 1064 nm and it is pumped with 67.8 mW of 532 nm laser light to observe squeezing levels of 1.96±0.0085 dB, with an antisqueezing level of 3.78±0.0150 dB. Our new locking technique allows the first experimental realisation of a pump-phase lock by read-out of the phase information pre-existing in the pump field. There is no degradation of the detected squeezed states.