Liquid Crystal Geometric Phase Holograms for Efficient Beam Steering and Imaging Spectropolarimetry

Efficient control and detection of light properties are important in modern Electro-Optic (EO) systems. One of the demands of the systems is directional control of light propagation for wide-angle with high efficiency. The ability to steer light source over a large field-of-regard is however difficult to achieve with high accuracy in mechanical platforms. Another important demand for the EO systems is a snapshot acquisition of light/scene with hyper-spectral and full polarization information. However, conventional technologies based on time-sequential measurements are not appropriate in high speed applications. Therefore, efficient light control and detection is essential technologies for the modern EO systems.;We have investigated and applied Geometric Phase Holograms (GPHs) as simple, compact, low-cost, light-weight, highly efficient alternatives to conventional optical beam steering and hyperspectral polarization imaging technologies. In this work, we have proposed novel polarization holography methods to record arbitrary phase profiles as diffractive GPHs based on revised Michelson and Mach-Zehnder interferometric setups. We have fabricated and experimentally demonstrated GPHs as liquid crystal diffractive optics with desirable optical properties that manifest nearly 100% efficiency, high polarization selectivity, and fast electro-optical switching. Moreover, we have introduced and demonstrated new polarization holography techniques that could record scalable period polarization holograms and arbitrarily changed polarization fields that produced various types of GPHs. We have also demonstrated a novel method that offered proximate lithography with easily tunable-periods with multi-axis polarization gratings fabrication method that could fabricate multiple diffraction at different azimuthal angles.;With the unique diffraction properties of the GPHs, we have achieved high throughput, wide-angle, nonmechanical laser beam steering utilizing stacked polarization gratings as one of GPHs. We have suggested and experimentally demonstrated four different steering designs and suggested optimum designs, which manifest their own advantages for various steering parameters and requirements. In this work, we have suggested and evaluated important nonmechanical designs, and derived governing theory of operation. We have also demonstrated a new way to accomplish continuous mechanical steering with high throughput and wide-angle utilizing a pair of rotating PGs. Moreover, we have demonstrated reduced chromatic dispersion of broadband source steering as utilizing compensation PGs that can adjust the color separation of PG diffraction.;Next novel technology, hyperspectral polarization imaging, using the unique dispersion properties of the GPHs has been introduced and experimentally demonstrated. GPHs have been used to implement snapshot hyperspectral polarization imagers that can provide simultaneous acquisition of both spectral and polarization information at a higher resolution and in a simpler way. We have developed the system matrix of the imaging system, and the matrix can be extendable to other GPH-based imaging systems. We have used numerical simulation to assess reconstruction performance, and showed a favorable comparison with prior work. We have also found that several potentially optimum GPH dispersion patterns, and identified favorable characteristics. Moreover, we have demonstrated working principle of the hyperspectral polarization imaging system with a derivation of governing operation theory and design principles.;In the final portion of this dissertation, we have evaluated the work, summarized the contributions, and made suggestions for how future researchers can take our work and contributions to new application spaces and new research areas.