Large Aspheres Manage High-Power Laser Energy

Laser system output power is constantly increasing. The maximum attainable peak power of laser pulses has increased by a factor of about 1000 every 10 years. This pace of progress is similar to the rapid advancements in integrated circuits described by Moore's law. Developments in optical coating, cleaning, and polishing technology enable optical manufacturers to fabricate components that can be used with high-power lasers, but high-power laser applications stretch - and often exceed - the limits of coating technologies. An alternative approach is to expand the laser beam diameter, spreading out the high-power light over a larger area. This reduces the likelihood of laser-induced damage to the optics but requires an increase in the size of optics used in the laser system. Aspheric lenses are often used to minimize the size of the focused spot, but fabrication challenges increase with asphere diameter. Understanding the challenges helps engineers to manage costs and delivery time.