Design and development of liquid crystal lenses

The use of optics in the fields of nano-technology, telecommunication and medicine has been growing exponentially in recent years. Application of liquid crystals within optics has been a growing trend from flat screen displays to variable focus lenses in a digital versatile discs. One area of the recent developments within optics has been the development of two-photon fluorescence microscopy and high-density three-dimensional optical data storage. In such applications, where a light beam has to be focused deep within the volume of bulk media, aberrations are introduced. The most dominant aberration is spherical aberration which results from the mismatch in refractive indices of the immersion and recording media. The aim of this thesis is to design a liquid crystal lens for dynamic tube length compensation of the spherical aberration. Liquid crystal phase plates are used in everyday liquid crystal displays (LCDs) such as mobile phones and calculators. The technologies required to manufacture a liquid crystal phase plate are well understood. However, an application like three-dimensional data storage requires different properties in the liquid crystal phase plate, which are investigated in this thesis. To fabricate our liquid crystal phase plate we used ZLI-5049-000 from MERCK as the liquid crystal medium, with poly-vinyl alcohol (PVA) and Indium Tin Oxide (ITO) providing the insulating and conducting layers, respectively. It has been demonstrated that vacuum vapour deposition can be used to coat a glass substrate with ITO. However, in order for the ITO coating to be conductive a method is developed where the substrate is heated to 300oC before, during and after the coating. Similarly, a method has been developed for producing a uniform 10