# Pulse delay time statistics in a superradiant laser with calcium atoms

## TL;DR

This paper reports on superradiant emission from cold calcium atoms in an optical cavity, analyzing pulse delay time statistics and demonstrating agreement with theoretical models, with implications for continuous wave laser development.

## Contribution

It presents the first detailed statistical analysis of pulse delay times in a calcium superradiant laser, confirming theoretical predictions and suggesting pathways for continuous wave operation.

## Key findings

- Pulse delay times fluctuate in agreement with theory
- Superradiant pulses are shorter than natural lifetime
- Emission intensity scales with the square of atom number

## Abstract

Cold samples of calcium atoms are prepared in the metastable $^{3}$P$_{1}$ state inside an optical cavity resonant with the narrow band (375 Hz) $^{1}$S$_{0} \rightarrow ^{3}$P$_{1}$ intercombination line at 657 nm. We observe superradiant emission of hyperbolic secant shaped pulses into the cavity with an intensity proportional to the square of the atom number, a duration much shorter than the natural lifetime of the $^{3}$P$_{1}$ state, and a delay time fluctuating from shot to shot in excellent agreement with theoretical predictions. Our incoherent pumping scheme to produce inversion on the $^{1}$S$_{0} \rightarrow ^{3}$P$_{1}$ transition should be extendable to allow for continuous wave laser operation.