Glass-ceramics (GC) are promising candidates for gradient refractive index (GRIN) optics. These multi-phase, composite materials also exhibit improved physical properties as compared to the parent base glass resulting from the formation of a secondary crystalline phase(s). Nanocrystal phase formation in a multi-component chalcogenide glass (ChG), (GeSe2-3As2Se3)(1-x)-(PbSe)x glass where x = 0-40 has been investigated, and the role of the starting material morphology has been correlated to the resulting composite's optical properties including refractive index, transmission, dispersion, and thermo-optic coefficient. Optical property evolution was related to the type and amount of the crystal phases formed, since through control of the local volume fraction of crystalline phase(s), the effective material properties of the composite can locally be varied. Through computational and experimental studies, tailored nanocomposites exhibiting gradient index properties have been realized. A Raman spectroscopic technique was developed as a means to spatially quantify the extent of conversion from glass to glass ceramic, and to confirm that the scale length of the local refractive index modification can be correlated to the extent of crystallization as validated by X-ray diffraction (XRD). Spatial control of the crystallization was examined by using a laser to locally modify the amount of nucleation and/or growth of crystallites in the glass. A novel technique converse to laser-induced crystallization was also developed and demonstrated that a glass ceramic could be locally re-vitrified back to a fully glassy state, through a laser-induced vitrification (LIV) method. Proof-of-concept demonstrator optics were developed using furnace and laser induced crystallization methods to validate experimental and computational approaches to modify the local volume fraction of nano-crystals. These demonstrators exhibited tailorable optical functionality as focusing optics and diffractive optics. This work paves the way for the design and fabrication of nanocomposite GRIN optics and their use in the mid-wave infrared.

At present, the energy of a single isolated attosecond pulse is limited to nanojoule levels. As a result, an intense femtosecond pulse has always been used in combination with a weak attosecond pulse in time-resolved experiments. To reach the goal of conducting true attosecond pump-attosecond probe experiments, a high flux laser source has been developed that can potentially deliver microjoule level isolated attosecond pulses in the 50 eV range, and a unique experimental end station has been fabricated and implemented that can provide precision control of the attosecond-attosecond pump-probe pulses. In order to scale up the attosecond flux, a unique Ti:-Sapphire laser system with a three-stage amplifier that delivers pulses with a 2 J energy at a 10 Hz repetition rate was designed and built. The broadband pulse spectrum covering from 700 nm to 900 nm was generated, supporting a pulse duration of 12 fs. The high flux high-order harmonics were generated in a gas tube filled with argon by a loosely focused geometry under a phase-matching condition. The wavefront distortions for the driving laser were corrected by a deformable mirror with a Shack-Hartmann sensor to significantly improve the extreme ultraviolet radiation conversion efficiency due to the excellent beam profile at focus. A high-damage-threshold beam splitter is demonstrated to eliminate energetic driving laser pulses from high-order harmonics. The extreme ultraviolet pulse energy is measured to be 0.3 microjoule at the exit of the argon gas target. The experimental facilities developed will lead to the generation of microjoule level isolated attosecond pulses and the demonstration of true atto pump-atto probe experiments in near future. Finally, in experiment, we show the first demonstration of carrier-envelope phase controlled filamentation in air using millijoule-level few-cycle mid-infrared laser pulses.

Mini-LED and micro-LED are emerging disruptive display technologies, because they can work as local dimmable backlight to significantly enhance the dynamic range of conventional LCDs, or as sunlight readable emissive displays. However, there are still unresolved issues impairing their display fidelity: 1) motion blur on high-resolution, large-size and high-luminance devices, 2) limited contrast ratio on mini-LED backlit LCD (mLED-LCD), 3) relatively high power consumption, and 4) compromised ambient contrast ratio. This dissertation tackles with each of these issues for achieving high display fidelity. Motion blur is caused by slow liquid crystal response time and image update delays. Low-duty ratio operation can suppress motion blur in emissive displays. However, it induces driving burdens on high-resolution, large-size and high-luminance mLED-LCD panel electronics and demands fast-response liquid crystals. In order to overcome these challenges, in Chapter 2, we propose a novel image-corrected segmented progressive emission method for mitigating the motion blur of mLED-LCDs. In parallel, in Chapter 3 and Chapter 4, we report new liquid crystal materials with submillisecond response time. High dynamic range displays require high peak luminance, true black state and high contrast ratio. While emissive displays intrinsically exhibit high contrast ratio, for LCDs it is limited to 1000:1 ~ 5000:1. In Chapter 5, we develop a simplified model for optimizing mLED-LCD to suppress the halo effect and achieve the same image quality as emissive displays. On the other hand, high luminance may give rise to short battery time and thermal management issues in displays with low power efficiency. In Chapter 6, we build a new model for mini-LED/micro-LED displays to simulate and optimize the power efficiency. In Chapter 7, we jointly consider the LED external quantum efficiency, system optical efficiency and structure-determined ambient light reflection to guide the designs for high ambient contrast ratio with optimal efficiency.

The insights offered by quantum mechanics to the field of optical metrology are many-fold, with non-classical states of light themselves used to make sensors that surpass the sensitivity of sensors using classical states of light. Unfortunately, this advantage, referred to often as "super-sensitivity" is notoriously fragile, and even the slightest experimental imperfections may greatly reduce the efficacy of the non-classical sensors, sometimes completely obviating their advantage. In my thesis I have shown that the performance of an otherwise ideal two-photon interferometer, which exploits entanglement between photons to make super-sensitive measurements of phase, is crippled by the slightest introduction of decoherence between modes of the interferometer. I have shown further that such drastic reduction in sensitivity can also appear in classical measurement problems, specifically that the recently developed methods of estimating the separation between a pair of point sources are rendered less effective when the ideal assumption of complete spatial incoherence is relaxed. Towards overcoming these and other issues, I have designed new configurations that use ancillary optical degrees of freedom, a tool-set that has recently garnered much interest in the field of quantum optics. In the context of two-photon interferometry, I have shown that by coupling polarization to the spatial-structure of the two photon state used to probe phase it is possible to obviate the need for a reference phase, even in the context of decoherence and imperfections in the interferometer. In the context of two-point resolution, I have developed an anisotropic imaging system that performs the function of an image-inversion interferometer and is inherently stable, offering an attractive implementation of recently developed methods of sub-Rayleigh imaging. I have further shown both theoretically and experimentally that the same anisotropic image-inversion interferometer is useful in measuring spatially encoded phases, both in the context of classical illumination as well as quantum-aided two-photon super-sensing. In both cases, the ability to perform interferometric measurements of the spatial structure of an electric field without splitting beam paths forms a bridge between conception and implementation of precision-sensing measurement strategies. Finally, I have shown that binary interferometric method based on the common-path anisotropic imaging system that I introduced, are able to measure both phase gradients and transverse beam tilts with a sensitivity beating conventional systems that are used both commercially and in research laboratories.

Over the years, optical fibers have dominated the landscape of communications. At the same time, these structures have been used in a variety of ways for nonlinear optical applications, including for example photonic crystal fibers, fiber amplifiers and multimode fibers. In this respect, optical fibers represent a good platform to study and discover linear and nonlinear phenomena, such as geometric parametric instabilities, which represent important processes that take place in systems having one or more parameters that vary periodically in time or space, and constitute an essential mechanism in supercontinuum generation in the normal dispersion regime in parabolic multimode fibers. In this work, we provide a rigorous analysis of geometric parametric instabilities in parabolic multimode fibers by taking into account dispersion effects to all orders and by considering self-focusing processes. This approach leads to results that are in good agreement with experimental observations of geometric parametric instabilities. In addition, we present a new method for generating self-similar pulses based on passive, normally dispersive multimode fibers that have an exponential taper profile. On the other hand, we theoretically analyzed and experimentally observed, for the first time in optics, Aharonov-Bohm suppression of light tunneling in a four-core twisted optical fiber, including an analytical solution for the equations of motion describing this system in the presence of nonlinearity. Finally, by taking advantage of the properties of non-Hermitian degeneracies we explore the prospect for an optical omni-polarizer based on a fiber loop system, where the output polarization state depends on the modulation applied to the intensity and phase of the corresponding polarization component.

This dissertation explores two main topics: Transient nonlinear refraction of air in Mid-IR spectral range and nonlinear optical properties of organometallic complexes. For seeing a vibrational and rotational Raman response the molecule should be Raman active. The first requirement for being a Raman active molecule is that the polarizability of molecule must be anisotropic. Linear symmetric molecules do have rotational Raman spectra. Not all the vibrational mode can be excited by a femtosecond pulse. The pulsewidth of our excitation beam should be less than the half of the vibration period. In this dissertation my excitation pulsewidth is not short enough to excite these vibrational modes and we ignored this contribution. The nonlinearity in both liquids and gases in general originates from both bound-electronic and nuclear responses. The bound-electronic response is an almost instantaneous response, however the nuclear response, simply because of the weight of nuclei, is a non-instantaneous response. For the nuclear response in the gas medium, we can ignore the libration and collision responses because of the low collision rates. We will also ignore the vibrational response since the bandwidth of the excitation pulse does not overlap with the first vibrational transitions of Oxygen and Nitrogen. For this reason the reorientational response is the only nuclear response contribution that we consider to the nonlinear refraction. Because of the low collision rates in the gases, the reorientational response does not damp quickly as it does in liquids and the molecules continue to rotate. Using short laser pulses with a broad bandwidth will excite coherently all the approximately rotational Raman lines. As a result, all the molecules that are occupying different rotational levels and therefore rotating at different rates will periodically rephase and results in pulsations of index of refraction. Since the nonlinearity arises from an instantaneous and non-instantaneous response we need to measure the nonlinearity with a time resolved technique. In addition, the relative polarization of pump and probe can greatly affect the observed nonlinear response. For these reasons we chose the time-resolved, polarization-sensitive, Beam-Deflection technique to perform our experiments. We performed both extremely nondegenerate and nearly degenerate experiments using the Near-IR and Mid-IR excitation beams and Mid-IR Probe to investigate the bound-electronic nonlinear refraction of air. To our knowledge, this is the first measurement of nonlinear refraction of air using both pump and probe in the Mid-IR. In addition to that, we explored the effect of pulsewidth of the excitation pulse on the nonlinear refraction by defining an effective nonlinear refractive index consisting of the effects of both the bound electronic response and reorientational response. We further analyzed the effect of changing the pressure and temperature on the pulsewidth dependence of effective nonlinear refraction. Finally, calculate the changes of effective nonlinear refraction for different layers of atmosphere using an atmospheric model From NASA. In the second major portion of this dissertation, we studied the nonlinear optical properties of organometallic complexes. These complexes were designed to have very high triplet quantum yields and fast intersystem crossing rates. Having very high singlet to triplet yields, makes these molecules good candidates for many applications. We studied seven different organometallic molecules. Three of these complexes were synthesized by our collaborators and the rest are commercially available. The majority of these molecules used iridium as the central metal while one used Ruthenium. Using the double pump-probe technique, which is a variation of pump-probe technique in order to decouple the singlet-triplet quantum yield from triplet cross-section. We performed our measurements using different sets of input fluences, using both pico-second and femto-second laser systems. We also developed a six-level electronic model that explains the complex nature of the interaction of optical pulses with some of these molecules. Our results show less than unity triplet quantum yields for these complexes. Since these molecules are believed to have very high triplet quantum yields, our results were contrary to our expectation.

X-ray diffraction tomography (XDT) is used to probe material composition of objects, providing improved contrast between materials compared to conventional transmission based computed tomography (CT). In this work, a small angle approximation to Bragg's Equation of diffraction is coupled with parallelized computing using Graphics Processing Units (GPUs) to accelerate XDT simulations. The approximation gives rise to a simple yet useful proportionality between momentum transfer, radial distance of diffracted signal with respect to incoming beam's location, and depth of material, so that ray tracing may be parallelized. NVIDIA's OptiX ray-tracing engine, a parallelized pipeline for GPUs, is employed to perform XDT by tracing rays in a virtual space, (x,y,zv), where zv is a virtual distance proportional to momentum transfer. The advantage gained in this approach is that ray tracing in this domain requires only 3D surface meshes, yielding calculations without the need of voxels. The simulated XDT projections demonstrate high consistency with voxel models, with a normalized mean square difference less than 0.66%, and ray-tracing times two orders of magnitude less than previously reported voxel-based GPU ray tracing results. Due to an accelerated simulation time, XDT projections of objects with three spatial dimensions (4D tensor) have also been reported, demonstrating the feasibility for largescale high-dimensional tensor tomography simulations.

The quest for ever higher information capacities has brought about a renaissance in multimode optical waveguide systems. This resurgence of interest has recently initiated a flurry of activities in nonlinear multimode fiber optics. The sheer complexity emerging from the presence of a multitude of nonlinearly interacting modes has led not only to new opportunities in observing a host of novel optical effects that are otherwise impossible in single-mode settings, but also to new theoretical challenges in understanding their collective dynamics. In this dissertation, we present a consistent thermodynamical framework capable of describing in a universal fashion the exceedingly intricate behavior of such nonlinear highly multimoded photonic configurations at thermal equilibrium. By introducing pertinent extensive variables, we derive new equations of state and show that any nonlinear multimoded optical systems that preserve power and energy will thermalize and settle to a Rayleigh-Jeans distribution. This thermalization processes are universal, regardless of the nonlinearity involved or the band structure of the systems. Moreover, each system has an unique equilibrium temperature and chemical potential once the initial conditions are determined. In addition, we show that both the "internal energy" and optical power in many-mode arrangements always flow in such a way so as to satisfy the second law of thermodynamics. The laws governing isentropic processes are derived and the prospect for realizing Carnot-like cycles is also presented. Subsequently, the prospect of all-optical cooling is investigated where the beam quality of an multimoded optical beam can be significantly improved through thermodynamic principles, driven by the second law of thermodynamics. We next provide an optical Sackur-Tetrode equation of nonlinear chain networks which explicitly gives the total relative entropy of such system in terms of the three extensive variables. Archetypical process including Joule expansion, heat conductivity, etc. are discussed basing on this formalism. In addition to shedding light on fundamental issues, our work may pave the way towards a new generation of high power multimode optical structures and could have ramifications in other many-state nonlinear systems, ranging from Bose-Einstein condensates to optomechanics.

Several metrics are commonly used to evaluate the performance of display devices. In this dissertation, we analyze three key parameters: fast response time, wide color gamut, and high contrast ratio, which affect the final perceived image quality. Firstly, we investigate how response time affects the motion blur, and then discover the 2-ms rule. With advanced low-viscosity materials, new operation modes, and backlight modulation technique, liquid crystal displays (LCDs) with an unnoticeable image blur can be realized. Its performance is comparable to an impulse-type display, like cathode ray tube (CRT). Next, we propose two novel backlight configurations to improve an LCD's color gamut. One is to use a functional reflective polarizer (FRP), acting as a notch filter to block the unwanted light, and the other is to combine FRP with a patterned half-wave plate to suppress the crosstalk between blue and green/red lights. In experiment, we achieved 97.3% Rec. 2020 in CIE 1976 color space, which is approaching the color gamut of a laser projector. Finally, to enhance an LCD's contrast ratio, we proposed a novel device configuration by adding an in-cell polarizer between LC layer and color filter array. The CR for a vertically-aligned LCD is improved from 5000:1 to 20,000:1, and the CR for a fringe field switching LCD is improved from 2000:1 to over 3000:1. To further enlarge CR to fulfill the high dynamic range requirement, a dual-panel LCD system is proposed and the measured contrast ratio exceeds 1,000,000:1. Overall speaking, such an innovated LCD exhibits supreme image qualities with motion picture response time comparable to CRT, vivid color to laser projector, and contrast ratio to OLED. Along with other outstanding features, like high peak brightness, high resolution density, long lifetime, and low cost, LCD would continue to maintain its dominance in consumer electronics in the foreseeable future.

High contrast ratio (CR) enables a display system to faithfully reproduce the real objects. However, achieving high contrast, especially high ambient contrast (ACR), is a challenging task. In this dissertation, two display systems with high CR are discussed: high ACR augmented reality (AR) display and high dynamic range (HDR) display. For an AR display, we improved its ACR by incorporating a tunable transmittance liquid crystal (LC) film. The film has high tunable transmittance range, fast response time, and is fail-safe. To reduce the weight and size of a display system, we proposed a functional reflective polarizer, which can also help people with color vision deficiency. As for the HDR display, we improved all three aspects of the hardware requirements: contrast ratio, color gamut and bit-depth. By stacking two liquid crystal display (LCD) panels together, we have achieved CR over one million to one, 14-bit depth with 5V operation voltage, and pixel-by-pixel local dimming. To widen color gamut, both photoluminescent and electroluminescent quantum dots (QDs) have been investigated. Our analysis shows that with QD approach, it is possible to achieve over 90% of the Rec. 2020 color gamut for a HDR display. Another goal of an HDR display is to achieve the 12-bit perceptual quantizer (PQ) curve covering from 0 to 10,000 nits. Our experimental results indicate that this is difficult with a single LCD panel because of the sluggish response time. To overcome this challenge, we proposed a method to drive the light emitting diode (LED) backlight and the LCD panel simultaneously. Besides relatively fast response time, this approach can also mitigate the imaging noise. Finally yet importantly, we improved the display pipeline by using a HDR gamut mapping approach to display HDR contents adaptively based on display specifications. A psychophysical experiment was conducted to determine the display requirements.