Towards single-cycle squeezing in chirped quasi-phase-matched optical parametric down-conversion

We propose a method for generation of a single-cycle squeezed light by parametric down-conversion in a chirped quasi-phase-matched nonlinear crystal. We find an exact quantum solution for this process valid for an arbitrary parametric gain, and discover an ultrabroadband squeezing in the down-converted light with flat squeezing spectrum comprising the full optical octave. We describe a scheme for observation of this kind of squeezing using second-harmonic generation as an ultrafast correlator.