Data are presented showing that quantum‐well (Lz∼200 A˚) AlxGa1−xAs‐GaAs‐AlxGa1−xAs heterostructures, grown by metalorganic chemical vapor deposition, can be operated as lasers on confined‐particle transitions over an unusually large range (&Dgr;&lgr;≳1000 A˚). The bandfilling properties of these quantum‐well heterostructures, which can easily be excited to carrier densities as high asn≳1019/cm3, are described. Quantum‐well laser diodes (x∼0.5) are described that operate (300 K) from the &Ggr; band edge to wavelengths as short as 7700 A˚ (&Dgr;E∼185 meV). Narrow photopumped samples (15–30 &mgr;m) are shown to operate (77 K) as lasers on clearly defined confined‐particle transitions from the band edge to 6980 A˚ (&Dgr;E∼270 meV). On samples from another wafer, laser operation has been observed to 6885 A˚ (&Dgr;E≡h&ngr;−Eg=293 meV). The photoluminescence spectra of these heterostructures extend well into the region of the recently determinedLband minima of GaAs.