The invention provides a light generating
system comprising a
first light generating device, a second light generating device, a diffuser element, a polarization changing element and a first
polarization beam splitter wherein: (A) the
first light generating device is configured to generate first device light having a first peak
wavelength ([
lambda] p1); wherein the second light generating device is configured to generate second device light having a second peak
wavelength ([
lambda] p2); wherein lambdap2-lambdap1 > = 10 nm; wherein the
first light generating device and the second light generating device each comprise a
diode laser or a super
light emitting diode; (B) the light generating
system is configured such that: (a) both the first device light and the second device light reaching the first polarizing
beam splitter comprise a first type of
linearly polarized light; (b) the first device light and the second device light propagate in a manner that: (i) at least a portion of the first device light and the second device light are reflected or transmitted at the first
polarization beam splitter, depending on the type of
linear polarization, via the first
polarization beam splitter; the first device light (iii) passes through a polarization altering element configured to convert
linearly polarized light into
elliptically polarized light (iii) to a diffuser element at which at least a portion of the first device light and at least a portion of the second device light are diffused into diffused first device light and diffused second device light, respectively, meanwhile, the direction of the
elliptically polarized light is changed into an opposite direction; (c) at least a portion of the diffused first device light and at least a portion of the diffused second device light propagate in such a manner that (i) through a polarization changing element at which at least a portion of the
elliptically polarized light is converted into a second type of
linearly polarized light different from the first type of linearly polarized light, to (ii) a first polarizing
beam splitter at which at least a portion of the diffused first device light and at least a portion of the diffused second device light are transmitted or reflected depending on the type of
linear polarization; and (C) the polarization changing element comprises a [
lambda] / 4 wave plate configured to be an (n / k1) [lambda] / 4 wave plate for a first peak
wavelength ([lambda] p1) and an (m / k2) [lambda] / 4 wave plate for a second peak wavelength ([lambda] p2), where n and m are odd positive integers, n-m is an even positive integer, and where k1 and k2 are each independently selected from the range of 0.8-1.2.