Spectral characterization of a SPDC source with a fast broadband spectrometer

TL;DR

This paper demonstrates a method to spectrally characterize a SPDC single-photon source using a fast broadband spectrometer, revealing how spectral properties vary with pump power and enabling pump photon analysis.

Contribution

It introduces a calibration and analysis technique for spectral characterization of SPDC sources using a novel spectrometer design, applicable to various single-photon sources.

Findings

Spectral properties of down-converted photons depend on pump power.

Spectrally similar down-converted photons observed under certain conditions.

Reconstruction of pump photon spectral information achieved.

Abstract

Knowing the properties of the single photons produced in a Spontaneous Parametric Down-Conversion (SPDC) source can be crucial for specific applications and uses. In particular, the spectral properties are of key relevance. Here, we investigate a commercial SPDC source using our fast broadband spectrometer. Our analysis is a valid method for other SPDC sources, as well as other single-photon generation techniques, thus providing a good example of how to use this spectrometer design. We calibrate the spectrometer using known lines of the argon emission spectrum. We show that the two down-converted photons from the SPDC source have different spectral properties depending on the pump power, and in which condition we measured spectrally similar down-converted photons. Lastly, we were able to reconstruct and investigate the spectral information for the pump photon.