Farfield dynamics of broad area vertical-cavity surface-emitting lasers: onset of partially coherent emission

Abstract

This study investigates a 50 mum-aperture broad-area vertical-cavity surface-emitting laser (BA-VCSEL) and studied its temporally and spatially resolved emission behaviour. For this, an intensified CCD-camera is employed with 300 ps shutter time, with which events of the BA-VCSEL's emission in quasi-cw operation is observed. The BA-VCSEL is pumped with 100 mus long current pulses with a repetition rate of 50 Hz. The farfield intensity distribution of the BA-VCSEL is measured. In addition, the nearfield intensity distribution is also measured by using an aspheric lens with an NA of 0.55 to image the nearfield onto the iCCD-camera