LOCAL OPTICAL SPECTROSCOPY OF SELF-ASSEMBLED QUANTUM DOTS USING A NEAR-FIELD OPTICAL-FIBER PROBE TO INDUCE A LOCALIZED STRAIN FIELD

We introduce and demonstrate a novel operating mode in near-field opti cal microscopy. The tip is used to simultaneously optically probe the sample and induce a highly localized strain in the area under study by pushing the tip into the sample. From knowledge of total tip-sample c ompression and tip geometry, we estimate the magnitude of stress, and show that localized uniaxial-like stresses in excess of 10 kbar can be achieved. We apply this method to a sample of InAlAs self-assembled q uantum dots. A blueshift of quantum dot emission lines consistent with estimates of the strain is observed, as well as a quenching of the ph otoluminescence with strain. (C) 1998 American Institute of Physics.