Positive-negative tunable liquid crystal lenses based on a microstructured transmission line

Abstract

In this work, a novel technique to create positive-negative tunable liquid crystal lenses is proposed and experimentally demonstrated. This structure is based on two main elements, a transmission line acting as a voltage divider and concentric electrodes that distribute the voltage homogeneously across the active area. This proposal avoids all disadvantages of previous techniques, involving much simpler fabrication process (a single lithographic step) and voltage control (one or two sources). In addition, low voltage signals are required. Lenses with switchable positive and negative focal lengths and a simple, low voltage control are demonstrated. Moreover, by using this technique other optical devices could be engineered, e.g. axicons, Powell lenses, cylindrical lenses, Fresnel lenses, beam steerers, optical vortex generators, etc. For this reason, the proposed technique could open new venues of research in optical phase modulation based on liquid crystal materials.

Multifunctional light beam control device by stimuli-responsive liquid crystal micro-grating structures

“…In previous numerical studies, we have revealed that the maximum relative deviation occurs at the mid-point of the inter-electrode gap. This value increases exponentially as the aspect ratio of the cell thickness over the gap becomes less than unity 40 .…”

“…Recently, we proposed a solution that overcomes the aforementioned shortcomings by employing a voltage transmission electrode and a set of closely spaced concentric electrodes 40 . The proposed device behaves like a multielectrode modal lens but with simple fabrication process and voltage control, using only one or two low-voltage signals.…”

“…In previous numerical studies, we have revealed that the maximum relative deviation occurs at the mid-point of the inter-electrode gap. This value increases exponentially as the aspect ratio of the cell thickness over the gap becomes less than unity 40 . In order to provide an estimate of the effect in the device here investigated, we have calculated the LC profile for the structure shown in Fig.…”

P‐81: Electrically Tunable GRIN Liquid‐Crystal Lenticular Lens Array with Short Focal Length

“…However, there is a restriction between tunable range of lens power and aperture size because of the limitation of birefringence of LC materials [6]. To overcome this obstacle, LC lenses based on multiple ring-shaped electrodes [7], Pancharatnam-Berry phase type [8] and Fresnel type [9] are proposed.…”

Engineering Aspheric Liquid Crystal Lenses by Using the Transmission Electrode Technique

“…It combines all the advantages of previous structures but fabrication and voltage control are much simpler and straightforward. By exploiting this technique, we have recently demonstrated axicon and spherical lenses [52], cylindrical and Powell lenses [53] and mutioptical systems [54].…”