Broadband bright twin beams and their up-conversion

TL;DR

This paper demonstrates broadband bright twin beams generated via high-gain parametric down-conversion in aperiodically poled lithium niobate, revealing exponential photon number scaling and ultrafast temporal correlations.

Contribution

It introduces the generation and characterization of broadband twin beams in aperiodically poled lithium niobate and measures their ultrafast correlations using sum-frequency generation.

Findings

Photon number scales exponentially with pump power.

Achieved 40 THz bandwidth for twin beams.

Measured 90 fs temporal cross-correlation peak.

Abstract

We report on the observation of broadband (40 THz) bright twin beams through high-gain parametric down-conversion in an aperiodically poled lithium niobate crystal. The output photon number is shown to scale exponentially with the pump power and not with the pump amplitude, as in homogeneous crystals. Photon-number correlations and the number of frequency/temporal modes are assessed by spectral covariance measurements. By using sum-frequency generation on the surface of a non-phasematched crystal, we measure a cross-correlation peak with the temporal width 90 fs.