developing a new class of high-energy rep-rated lasers
Over the past 40 years, high-energy laser systems have used glass disc amplifiers because they can be fabricated with very large apertures. While these systems have scaled in energy, they share the same architecture – flashlamp pumped multi-slab Nd:Glass discs at Brewster’s angle.
The glass discs in these systems are cooled by radiative emission into the surrounding environment. This limits their typical effective repetition rate to a single shot every 30 minutes to 3 hours.
Over the past two years, National Energetics has been developing a next-generation disc laser that overcomes the disc cooling issue and promises to lead to a new class of high-energy rep-rated lasers. The architecture consists of a cassette containing multiple discs with liquid cooling flowing between them. The laser beam passes through the coolant as well as the disc elements.
The disc cartridge is mounted in a modular reflector assembly and is pumped on both sides by banks of flashlamps. The unit has been tested at 0.1 Hz with excellent results. Each assembly stores over 250J of energy, which can be extracted with excellent beam quality and minimal wavefront distortion.
A laser incorporating these amplifier modules is currently under construction at National Energetics. The laser consists of a special temporally shaped front end followed by a series of rod amplifiers which is then injected into seven disc amplifier modules with an open aperture of 180mm in a 4-pass configuration. The final output specification is 400J 527 nm.
National Energetics has extensively modeled this disc amplifier design and our theoretical models closely match the characterized output of the amplifier. We can confidently predict alternative designs using the amplifier and we can scale both up into higher energies and into alternative materials and smaller apertures for higher repetition rates. Although this design is flashlamp-pumped, diode pumping is a possibility.
For more information on our disc laser technology and how it can work for you, contact us.