LED pumped lithium neodymium tetraphosphate lasers

Laser action in lithium neodymium tetraphosphate, LiNdP
4
O
12
(LNP), crystals, pumped with Al
x
Ga
1-x
As electroluminescent diodes, is reported, citing both end- and side-pump configurations. The threshold incident light-emitting diode (LED) intensities at about -30°C are 14.9 W/cm
²
and 7.2 W/cm
²
for end and side pump, respectively. Temperature dependences of threshold, stimulated emission cross section, and round-trip loss were measured experimentally. Possibility of room-temperature CW operation, maximum output power, and optimum coupling are discussed. Taking account of improvements of pumping optics, crystal homogeneity and LED structure, LED intensities required for room-temperature CW operation are 35 W/cm
²
and 8.5 W/cm
²
for end and side pump, respectively.