# Electrically pumped semiconductor laser with low spatial coherence and directional emission

## TL;DR

This paper presents an on-chip semiconductor laser that achieves low spatial coherence and directional emission by optimizing cavity geometry, enabling ultrafast decoherence suitable for speckle-free imaging.

## Contribution

It introduces a novel cavity design that maximizes transverse lasing modes to rapidly reduce spatial coherence in a compact laser source.

## Key findings

- Achieves rapid decoherence in a few nanoseconds
- Produces a highly directional laser beam
- Enables speckle-free ultrafast imaging

## Abstract

We design and fabricate an on-chip laser source that produces a directional beam with low spatial coherence. The lasing modes are based on the axial orbit in a stable cavity and have good directionality. To reduce the spatial coherence of emission, the number of transverse lasing modes is maximized by fine-tuning the cavity geometry. Decoherence is reached in a few nanoseconds. Such rapid decoherence will facilitate applications in ultrafast speckle-free full-field imaging.