3D Structure with Larger-scale Variation in Periodic Properties

Applications

The immediate application is improved quality and lower cost GRIN lenses. Also it can be applied to optical communications or opto-semiconductor applications.

Problem Addressed

Coherent diffraction lithography or the Talbot effect is a method of optically replicating periodic structures. When coherent light is directed to a periodic amplitude or phase mask, 3D light intensity distribution behind the mask can be imaged in a thick photopolymer. However, the application of the Talbot effect is limited to replicating periodic patterns and sensitive to defects introduced during processing.

Technology

This invention is about advanced Talbot effect lithography. In this method, some aspect of the mask periodicity (i.e. the duty cycle, geometry, period length or phase shift) is varied significantly but gradually over a distance. It can be further replicated as 3D polymer scaffolds with 2D gradients in porosity, which have gradient index (GRIN) due to the refractive index contrast between the polymer and air. The light is directed through the volume of the material by the special gradients within the structures, which can act as a lens.

Advantages

  • Simple & low cost fabrication
  • Compact size (thin & small)
  • Aberration corrected lenses