Room-temperature optically pumped (Zn,Mg) (S,Se)/(Zn,Cd)Se laser struc
tures have been grown by molecular beam epitaxy. Using of alternativel
y-strained short-period superlattice waveguide results in low threshol
d power density values over the whole blue-green (470-520 nm)wavelengt
h range. Incorporation of CdSe fractional monolayer active region prov
ides more than fourfold further decrease in threshold with respect to
quantum well laser structure. Optical and structural properties of las
er structure with 2.8 monolayer CdSe are discussed in detail.