The emission profiles of laser diodes working at 780 nm and 1300 nm are studied by near‐field scanning optical microscopy. As the near‐field probe is scanned across the laser mirror facet, the laser emission induces a transient expansion of the probe tip which is monitored using shear force microscopy. The thermal expansion of the tips reaches absolute values of up to 100 nm per mW of emitted laser power. A fully metallized near‐field probe tip is shown to serve as a local bolometer with a spatial resolution of better than 1 &mgr;m. ©1996 American Institute of Physics.