Exploiting the sensitivity and the self‐aligning features of the confocal laser‐feedback technique and the convenience of superluminescent laser diodes, we developed an optical method for imaging and profiling surface microstructures with a depth resolution as great as 20 nm. The incoherent, noninterferometric nature of the technique enables fast open‐loop operation and large dynamic range. Measurements of calibrated semiconductor surface microstructures and optical ridge waveguides are demonstrated. ©1995 American Institute of Physics.