Broadband diffraction of correlated photons from crystal superlattices

TL;DR

This paper demonstrates broadband quantum correlated photon generation using a lithium niobate superlattice, revealing a comb-like spectral emission with potential applications in quantum technologies and an analogy to optical diffraction.

Contribution

It introduces a novel superlattice design for broadband photon generation via spontaneous parametric down-conversion, enabling a wide spectral bandwidth and nonlinear interference effects.

Findings

Observed comb-like emission spanning 0.060 um to 1.4 um

Achieved spectral bandwidth at 0.647 um and 3.0 um wavelengths

Established an analogy between quantum and classical optical diffraction

Abstract

Sources of broadband quantum correlated photons present a valuable resource for quantum metrology, sensing, and communication. Here, we report the generation of spectrally broadband correlated photons from frequency nondegenerate spontaneous parametric down-conversion in a custom-designed lithium niobate superlattice. The superlattice induces a nonlinear interference, resulting in an experimentally observed comb-like emission spanning 0.060 um and 1.4 um of spectral bandwidth at 0.647 um and 3.0 um wavelengths, respectively. In addition to useful technological applications, our concept offers an interesting analogy between optical diffraction in quantum and classical optics.