Microfluidic microlenses for nanotechnology applications: production, modeling, and fabrication techniques

Abstract

The importance of micro-optical elements for the development of hi-tech products is now clear. However there is a wide range of fabrication techniques used to produce these optical components, each having advantages and disadvantages. It is vital therefore that this range of fabrication techniques are examined and compared. One of the most promising fabrication techniques, the photoresist reflow method, will be discussed in detail. Particular emphasis shall be given to the case where the lens profiles differ from that predicted by the current energy minimization models. This case is of interest as it allows the production of aspheric lenses which have a wide range of applications including, beam shaping, power transfer and fiber coupling. The fabrication of these aspheric lenses using the photoresist reflow method currently requires an iterative experimental process as there is currently no model that accurately predicts the lens profiles from first principles. In this paper we examine a proposed model that is based on first principles, the Curvature Correction Model, CCM, and attempt to verify its applicability to the photoresist reflow method. In this paper we examine a current methods used to solve the CCM and discuss the predicted lens profiles. The resulting lens profiles allow us to predict initial fabrication parameters to enable us to design specific lens profiles. Further examination of a number of polynomial models that have been presented in the literature is also carried out.