Optical harmonic generation from bright squeezed vacuum

Multi-photon processes are extremely important in optics. Optical harmonics generation, multi-photon absorption, ionization, polymerization or spectroscopy are widely used in practical applications. The efficiency of these processes depends on many factors, one of them being the statistics of the incident light. Indeed, the rate of an n-photon effect scales as the n
^th
-order autocorrelation function g
⁽ⁿ⁾
of the incident light [1]. Therefore light sources with high correlation functions can enhance the efficiency of such effects by several orders in magnitude compared to coherent light with the same wavelength, pulse duration and energy per pulse. Here we demonstrate this enhancement in the generation of optical harmonics from bright squeezed vacuum (BSV), which can have thermal (g
⁽ⁿ⁾
=n!) or superbunched (g
⁽ⁿ⁾
=(2n-1)!!) statistics depending on the spectral filtering [2].