SPECTRALLY RESOLVED NEAR-FIELD MODE IMAGING OF VERTICAL-CAVITY SEMICONDUCTOR-LASERS

The transversal mode properties of vertical cavity surface emitting la sers (VCSELs) are studied by spectrally resolved scanning near-field o ptical microscopy. In contrast to classical optical microscopy techniq ues, our method is able to simultaneously decompose lasing transversal modes by their wavelength with lateral superresolution. As the tip-sa mple distance is controlled by the well-established shear-force detect ion, additional topographical information showing the surface structur e of the laser is provided. Therefore, near-field spectroscopy allows the detailed analysis of the spatial light distribution emitted by the laser with respect to the current injection contact, making it a prom ising tool for the characterization and optimization of VCSELs. (C) 19 96 American Institute of Physics.