Beam shaping for a high-power vertical cavity surface emitting laser

A high-power vertical cavity surface emitting laser (VCSEL) is described that can emit over 40 mW in pulsed operation at 780 nm. The mode structure of the device is unusual, in that only the HE³¹ mode lazes over a broad environment of mechanical and thermal conditions. The stable mode structure suggests that this laser may be used in an optical system like those used in optical data storage, which demand diffraction-limited performance. However, the laser mode cannot be used directly in a classical optical system due to its ring amplitude and periodic phase properties. In this paper, we discuss potential beam-shaping techniques that can be used to overcome these limitations. For example, a simple phase mask can be used to eliminate the periodic phase properties. Optical systems for focusing the shaped laser light are also discussed.