High-power diode laser technology XX: a retrospective on 20 years of progress

The High-Power Diode Laser Technology conference was first presented at SPIE Photonics West in 2003. At that time high power laser diodes were just approaching 50-60% in efficiency, a couple of companies were developing systems based on these diodes, and fiber lasers were not yet an industrial product. Since then, laser diodes can exceed 70% electrical efficiency, power levels have grown from the 50-Watt bar level to today's heights of several hundred Watts. New wavelengths have been introduced and laser diode systems have increased in power from the couple of kWatts in 2003 to over 40 kWatts today. This technology area continues to expand with new applications, and new heights every year. We will review the hot topics of the time, technology, applications, and state-of-the art performance levels. What problems have been solved, and which remain today, twenty years later?