It is well known that in a three-level lambda
system, spontaneous emission decay rate on the lasing
transition must be smaller than or equal to the decay
rate on the driving transition in order to observe LWI.
Since spontaneous emission rate is proportional to cube
of the corresponding transition frequency, satisfying the
above condition requires the frequency of lasing transition
to be smaller than the driving transitions frequency.
In other words, according to this condition, frequency upconversion
is not possible with LWI. The main theme of
this article is to suggest the possibilty of frequency upconversion
in LWI by overcoming the condition described