The lasing threshold is the lowest excitation level at which a laser's output is dominated by stimulated emission rather than by spontaneous emission.
View page
BURAT means Lasing in Bicol
View page
It's the current you have to inject into the device so that the
gain inside it is equal to the losses due to absorption and
scattering of the light generated. When you have reached this
amount of gain, then lasing can start to occur.