Tunable High-Resolution Macroscopic Self-Engineered Geometric Phase Optical Elements

Abstract

Artificially engineered geometric phase optical elements may have tunable photonic functionalities owing to their sensitivity to external fields, as is the case for liquid crystal based devices. However, liquid crystal technology combining high-resolution topological ordering with tunable spectral behavior remains elusive. Here, by using a magnetoelectric external stimulus, we create robust and efficient self-engineered liquid crystal geometric phase vortex masks with a broadly tunable operating wavelength, centimeter-size clear aperture, and high-quality topological ordering.

Q-plate technology: a progress review [Invited]

“…3D here stands for involving all three orthogonal field components, as already demonstrated in pioneering works such as the polarization Möbius strip [13], but also for space-variant in all three spatial coordinates, as in 3D-structured optical pulses. We expect that suitable q-plate elements in combination with other kinds of optical technologies will be able to improve the control on obtained structured light, for example by better combining radial and azimuthal structuring [109], improving the spatial resolution [110], and push the boundary of achievable structures even further. This in turn may find applications in more advanced optical manipulation (optical tweezers), optical material processing, optical filtering and coronagraphy, or in light-matter space-time-modulated interaction a, for example for quantum simulations with atoms or ions.…”

Multispectral Management of the Photon Orbital Angular Momentum

“…2(c). There, the twisted extinction crosses, whose right or left handedness is randomly selected as the defect is spontaneously generated from the unperturbed initial LC state, are a generic manifestation of localized umbilical nematic LC defects with q ¼ þ1 resulting from the elastic anisotropy of the LC [16,17]. This modifies the wavefront curvature without altering the orbital angular momentum control operated by every topological pixel.…”

Electrically activated spin-controlled orbital angular momentum multiplexer

“…Here, we propose to cascade two high-resolution flat-optics elements, namely a diffractive OAM multiplexer with a dynamical OAM shifter. This is done in a compact manner, without additional technological complexity and without clear-aperture drawbacks, by using a recently introduced self-engineered liquid crystal optical element [18]. This allows us to report experimentally on the demonstration of on-demand spin-controlled OAM multiplexing of light.…”

“…Such an element behaves as a transmission phase mask associated with the polarizationdependent phase functions Ω LC = 2σqφ on the circular polarization basis, where σ=±1 refers to the helicity of light. Here we implement a novel approach combining high-resolution of the phase pattern, large clear aperture and electrical reconfigurability, without need of any machining technique [18]. It consists in using a layer of nematic LC (mixture MLC-2048, Merck) with thickness = 20 m that is sandwiched between two glass substrates provided with transparent electrodes.…”

“…above a threshold voltage [27]. We get rid of this drawback by adding a static magnetic field from a ring-shaped macroscopic (centimetre size) permanent magnet [18], which pins a defect with q=+1 centered on the revolution axis of the magnet while preserving the inherent high-quality topological ordering of self-engineered approaches [27][28][29][30] as well as the electrical control features of liquid crystal q-plates [31]. Obtained macroscopic magneto-electric optical vortex phase mask observed between crossed linear polarizers is shown in Fig.…”