The paper ‘Fabrication of diffractive optical elements by programmable thermocapillary shaping of thin liquid films‘ proposed a new method to fabricate diffractive optical elements, that is, using the variable temperature distribution to induces surface tension gradients in the polymer-air interface. Gradient surface tension leads to the deformation of the interface, and the two-dimensional temperature distribution is controlled by the illumination of digital micromirror device (DMD) guided light. The light pattern and intensity can be easily modified by DMD, thus the temperature, and further the deformation of the surface. This is so called ‘programmable’. When the surface condition is fulfilled, the fast prototyping is realized by exposing the UV resin under the UV light. In this way, a DOE can be fabricated.
One point in the paper that attracts me is the concept and flow of solving an inverse problem from the desired surface shape to the necessary temperature. This part is worth digging and may be utilized in other areas.