Optical feedback from the target can destroy laser components unless it is prevented from reentering the laser. Conventional Faraday rotator-polarizer isolators are lossy, and their cost increases nonlinearly with the beam diameter to the 2.5 power, precluding their use at large aperture. A 46-cm isolator, for example, costs $500,000 for each of the 20 Nova beams. Each plasma shutter will cost $80,000/beam line.
© 1982 Optical Society of AmericaPDF Article