Use of quasi-phase-matched (QPM) materials for parametric chirped pulse amplification (PCPA) substantially reduces the required pump peak power and pump brightness, allowing exploitation of spatially-multimode and long duration pump pulses. It also removes restrictions on pump wavelength and amplification...http://www.google.com/patents/US6181463?utm_source=gb-gplus-sharePatent US6181463 - Quasi-phase-matched parametric chirped pulse amplification systems
