Microlenses are formed on a substrate having a first absorption within an operational wavelength range, and a second absorption outside the operational wavelength range, wherein the second absorption is greater than the first absorption. One or more waveguides are coupled with a processing light beam having a wavelength outside the operational wavelength range, and the processing light beam is directed through the waveguides to the substrate to locally heat and expand the substrate so as to form microlenses on the substrate surface. The processing light beam is terminated to stop heating of the substrate and fix the microlenses.