Low aberration and fast switching microlenses based on a novel liquid crystal mixture

Abstract

In this work, we present a novel kind of LC mixture (5005) for photonic applications, with emphasis on a LC microlens array. This mixture is a nematic composition of three different families of rod like liquid crystals. The key is that frequency dependence of parallel component of electric permittivity is different for each component, resulting in a strongly dependent on frequency dielectric anisotropy. The unique properties of this LC mixture are demonstrated to work in a frequency modulated LC microlens array. A hole patterned structure is used. Thanks to the special characteristics of this mixture, the microlenses are reconfigurable by low voltage signals with variable frequency. This is a first demonstration of a LC lens with tunable focal length by frequency in an analog way. The result of this type of control are microlenses with low aberrations and fast switching (the frequency switching is around 10 times faster than amplitude modulation). The tunability with frequency and the fast switching, makes this liquid crystal of special interest not only for microlenses but for all kind of optical phase modulators.

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

“…Specifically, LC-tunable optical phase modulation is one of the most important uses, which has attracted significant attention for years 1 . Currently, it is a very researched topic, for example in ophthalmological applications 2 , 3D vision applications [3][4][5][6] , beam steering 7 , optical vortices [8][9][10][11] , tunable zooming 12 , aberration correctors 13 , astronomy 14 , novel aberration correctors 15 , multi-optical elements 16 , micro-axicon arrays 17 , multi-focal 18 , high fill-factor 19 and frequency controlled 20 microlenses, lensacons, and logarithmic axicons 21 , etc. High among those are adaptive-focus lenses, which were first proposed more than 40 years ago and still are a hot topic.…”

Multifrequency Driven Nematics

“…This dependence gives raise to the possibility of designing liquid crystal mixtures with very low relaxation frequencies of electric permittivity parallel ε , which is useful for many applications [16]. Apart from traditional SLM, the unique properties of this LC mixture can be used in all kind of optical phase modulators recently reported, e.g., adaptive lenses [17], beam steering [18], correction of aberrations [19], 3D vision applications [19][20][21][22], novel aberrations correctors for rectangular apertures [23], microaxicon arrays [24], multioptical elements [25], hole-patterned microlenses [26], multifocal microlenses [27], high fill-factor microlenses [28], frequency controlled [29] microlenses, optical vortices [30], lensacons, and logarithmic axicons [31]. The LC mixtures used in this work have been designed by mixing three different families of LC compounds to meet the requirements of the LC to be controlled by low frequencies of the electrical applied voltage.…”

Depth-of-Field-Extended Plenoptic Camera Based on Tunable Multi-Focus Liquid-Crystal Microlens Array

“…Specifically, among the three main designs, the plenoptic camera based on the MLA has a very promising development prospect due to its small size, low cost, and light-field acquisition in a single photographic exposure. Recently, liquid-crystal microlens array (LCMLA)-based plenoptic cameras have attracted a lot of research interest [16][17][18][19], which is owed to the advantages of easy integration with other devices, 2D/3D switchability, ease of manufacture [18][19][20][21][22][23], and, most important, excellent tunability due to the redistribution of liquid-crystal (LC) molecules in the applied electric field [24][25][26][27][28][29][30][31][32][33][34][35][36][37]. Such an excellent tunability enables 2D/3D switchable modes and an extended DOF for LCMLA-based plenoptic cameras [17,18,30].…”