Measuring intensity correlations of a THz quantum cascade laser around its threshold at sub-cycle timescales

TL;DR

This paper presents the first room temperature measurement of THz photon correlations with sub-cycle temporal resolution, enabling detailed analysis of quantum light emitted by a THz Quantum Cascade Laser at its threshold.

Contribution

It introduces a novel electro-optic sampling method for measuring THz photon statistics with sub-cycle resolution at room temperature.

Findings

First measurement of g1(τ) and g2(τ) in THz range at room temperature

Achieved sub-cycle temporal resolution of 146 fs

Measured photon statistics at the threshold of a THz Quantum Cascade Laser

Abstract

The quantum nature of photonic systems is reflected in the photon statistics of the light they emit. Therefore, the development of quantum optics tools with single photon sensitivity and excellent temporal resolution is paramount to the development of exotic sources, and is particularly challenging in the THz range where photon energies approach kbT at T=300 K. Here, we report on the first room temperature measurement of field g1({\tau}) and intensity correlations g2({\tau}) in the THz range with sub-cycle temporal resolution (146 fs) over the bandwidth 0.3-3 THz, based on electro-optic sampling. With this system, we are able to measure the photon statistics at threshold of a THz Quantum Cascade Laser.