The present disclosure describes broadband optical emission sources that include a stack of semiconductor layers, wherein each of the semiconductor layers is operable to emit light of a different respective wavelength; a light source operable to provide optical pumping for stimulated photon emission from the stack; wherein the semiconductor layers are disposed sequentially in the stack such that a first one of the semiconductor layers is closest to the light source and a last one of the semiconductor layers is furthest from the light source, and wherein each particular one of the semiconductor layers is at least partially transparent to the light generated by the other semiconductor layers that are closer to the light source than the particular semiconductor layer. The disclosure also describes various spectrometers that include a broadband optical emission device, and optionally include a tuneable wavelength filter operable to allow a selected wavelength or narrow range of wavelengths to pass through.