Fast diffraction-limited cylindrical microlenses

We describe a technique for fabricating fast well-corrected cylindrical microlenses for applications such as collimating laser diodes and coupling light into and out of integrated optics devices. The lenses are produced by first grinding a glass preform to a desired cross-sectional shape and then heating and drawing the preform into a fiber of the desired diameter. The heating and drawing operations polish the glass surface and reduce the cross-sectional dimensions but maintain the cross-sectional shape. Diffraction-limited 220-microm focal length immersion lenses with numerical aperture >0.6 have been demonstrated.