Optical spectroscopy of individual segments of interband cascade diode laser Nanostacks/spl reg/

Monolithically stacked high-power laser structures, i.e. device structures that include two or more nominally identical waveguide segments separated by a specially designed tunnel junction, are designed as high-brightness coherent radiation source predominantly for pulsed operation applications. Additional technological advantages are related to reduced operation currents that need to be provided by the power supply. Such so-called Nanostack/spl reg/ structures are investigated by near-field scanning optical microscopy (NSOM). This method provides straightforward and separate access to the properties of both optically active segments. Device emission, namely electroluminescence (EL) and lasing, as well as photoluminescence (PL) and photocurrent (PC) data are recorded separately from both device segments with ultra-high spatial resolution.