  Current methods for fabricating lenses rely on mechanical processing of the
lens or mold, such as grinding, machining, and polishing. The complexity of
these fabrication processes and the required specialized equipment prohibit
rapid prototyping of optical components. This work presents a simple method,
based on free-energy minimization of liquid volumes, which allows to quickly
shape curable liquids into a wide range of spherical and aspherical optical
components, without the need for any mechanical processing. After the desired
shape is obtained, the liquid can be cured to produce a solid object with
nanometric surface quality. We provide a theoretical model that accurately
predicts the shape of the optical components, and demonstrate rapid fabrication
of all types of spherical lenses (convex, concave, meniscus), cylindrical
lenses, bifocal lenses, toroidal lenses, doublet lenses and aspheric lenses.
The method is inexpensive and can be implemented using a variety of curable
liquids with different optical and mechanical properties. In addition, the
method is scale-invariant and can be used to produce even very large optical
components, without a significant increase in fabrication time. We believe that
the ability to easily and rapidly create high-quality optics, without the need
for complex and expensive infrastructure, will provide researchers with new
affordable tools for fabricating and testing optical designs.
