Quantum frequency conversion, the process of shifting the frequency of an optical quantum state while preserving quantum coherence, can be used to produce non-classical light at otherwise unapproachable wavelengths. We present experimental results based on highly efficient sum-frequency generation (SFG) between a vacuum squeezed state at 1064 nm and a tunable pump source at 850 nm ± 50 nm for the generation of bright squeezed light at 472 nm ± 4 nm. We demonstrate that the SFG process conserves part of the quantum coherence as a 4.2(±0.2) dB 1064 nm vacuum squeezed state is converted to a 1.6(±0.2) dB tunable bright blue squeezed state.
Quantum frequency conversion, the process of shifting the frequency of an optical quantum state while preserving quantum coherence, can be used to produce non-classical light at otherwise unapproachable wavelengths. We present experimental results based on highly efficient sum-frequency generation (SFG) between a vacuum squeezed state at 1064 nm and a tunable pump source at 850 nm
± 50 nm for the generation of bright squeezed light at 472~nm
± 4~nm, currently limited by the phase-matching of the used nonlinear crystal. We demonstrate that the SFG process conserves part of the quantum coherence as a 4.2(
±0.2)~dB 1064 nm vacuum squeezed state is converted to a 1.6($\pm
0.2) dBtunablebrightbluesqueezedstate.Wefurthermoredemonstratesimultaneousfrequency−andspatial−modeconversionofthe1064−nmvacuumsqueezedstate,andmeasure1.1(\pm
0.2) dBand0.4(\pm
0.2) dBofsqueezingintheTEM_{01}$ and TEM
02 modes, respectively. With further development, we foresee that the source may find use within fields such as sensing, metrology, spectroscopy, and imaging.