Longitudinally pumped miniature lasers are inefficient, partly because of their inefficient absorption of the pump light. Scavenging the unabsorbed pump light to pump an in-line amplifier can greatly enhance the efficiency of the system, with minimal added cost, size, or complexity.
© 2004 Optical Society of America
J. J. Zayhowski and A. L. Wilson, Jr., "Energy-scavenging amplifiers for miniature solid-state lasers," Opt. Lett. 29, 1218-1220 (2004)