Controllable shifting, steering, and expanding of light beam based on multi-layer liquid-crystal cells

Urban Mur,Miha Ravnik,David Seč

doi:10.1038/s41598-021-04164-0

Urban Mur, Miha Ravnik + Show 1 more

Open Access

https://doi.org/10.1038/s41598-021-04164-0

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Abstract

Shaping and steering of light beams is essential in many modern applications, ranging from optical tweezers, camera lenses, vision correction to 3D displays. However, current realisations require increasingly greater tunability and aim for lesser specificity for use in diverse applications. Here, we demonstrate tunable light beam control based on multi-layer liquid-crystal cells and external electric field, capable of extended beam shifting, steering, and expanding, using a combination of theory and full numerical modelling, both for liquid crystal orientations and the transmitted light. Specifically, by exploiting three different function-specific and tunable birefringent nematic layers, we show an effective liquid-crystal beam control device, capable of precise control of outgoing light propagation, with possible application in projectors or automotive headlamps.

Highlights

Shaping and steering of light beams is essential in many modern applications, ranging from optical tweezers, camera lenses, vision correction to 3D displays
Nematic director profiles are both calculated by a full tensorial Landau-de Gennes free energy minimisation a pproach[50,51] and set by different analytical Ansatz functions mimicking either numerically or experimentally known fields
By using a free energy minimisation we show on a selected example how the used nematic director fields can possibly be created in practice by use of different anchoring types at the boundaries and applying static electric field as induced by electrodes with fixed electric potentials

Summary

Introduction

Shaping and steering of light beams is essential in many modern applications, ranging from optical tweezers, camera lenses, vision correction to 3D displays. Multiple adjacent LC cells can be used to improve steering angle in a dual-twist Pancharatnam phase d evice[40], where deflection angles up to 80◦ can be obtained and still maintaining very high efficiency Expanding these effects, wave front shaping and switching between different helical modes can be achieved by a cascade of Pancharatnam-Berry phase optical elements[41]. Higher power laser beams can realign the nematic director configuration and create a self-confining extraordinarily polarized laser beam with no diffraction, which propagates at a walk-off a ngle[36] This angle can be tuned with reorientation of the bulk nematic configuration, either via e lectric[43] and magnetic fields[44,45] or different colloidal inclusions[46,47]. We explore as the central scientific question the use of (three) close-stacked liquid crystal layers for light beam modulation and control, using combination of theory and full numerical simulations based on fmf.uni-lj.si

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