The manufacture of microlenses by melting photoresist

It has been shown that it is possible to to generate very small lenses by melting 'islands' of photoresist on a glass substrate. The authors have made lenses with diameters ranging from 5 mu m to 750 mu m in the form of spheres, cylinders and crossed cylinders and have studied their optical properties. Lenses with numerical apertures between 0.5 and 0.2 may be made close to diffraction limited but those of lower numerical aperture can only be achieved using more complex techniques.