<p> Gyromagnetic phenomena have been of interest since the dawn of modern electromagnetic theory. While rotation-induced magnetization in electronic systems has been known for over 100 years, the phenomenon remains largely unexplored in nuclear degrees of freedom. This thesis explores the influence of external angular momentum on nuclear polarization, utilizing optical fields endowed with orbital angular momentum (OAM). To that end, I employ novel holographic methods to project light fields with programmable OAM content into fluid samples. To quantify the OAM in such fields, I introduce new techniques of holographic video microscopy to characterize optical forces. These optical manipulation and detection schemes are combined with standard NMR spectroscopy to reveal the effects of optical forces on the nuclear hyperpolatization of both absorbing and non-absorbing samples. These experiments provide evidence of a non-resonant coupling between the orbital angular momentum of light and nuclear spins.</p>

The need for bandwidth at the access level has driven the development of many new multiple access schemes. This paper explores a spectral encoding scheme for Optical CDMA, in which bipolar communication is accomplished by an optical chip based on planar waveguide technology. A computer model of the planar waveguide encoder/decoder is developed and used to characterize the proposed optical chip. The model is then refined by the integration of data taken from an 8 channel AWG. The simulations indicate that bit error rates (BER) of 10-9 are possible for systems as large as 32 channels.

In this thesis, the plasmon hybridization method is extended theoretically to explore the optical properties of curvilinear particles, high symmetry clusters, and infinite periodic systems of nanoparticles. Plasmon hybridization is a recently-developed theory used to describe the collective oscillations of conduction electrons in metallic nanoparticles (plasmons). Here curvilinear particles refer to solid nanoparticles, dielectric cavities in an infinite metal, or nanoparticles consisting of a dielectric core surrounded by a thin metallic shell (core/shell particles) that can be described using a coordinate system with a completely separable solution to the Laplace equation. I find that there is a common form for the plasmon frequencies of such particles among all completely separable coordinate systems and that the plasmons of core/shell particles can be viewed as a hybridization resulting from the interaction of solid particle and cavity plasmons. I specifically analyze the plasmons of prolate, oblate, and cylindrical particles, three experimentally relevant geometries. High symmetry clusters are collections of nanoparticles that exhibit the symmetry of a point group. I study the plasmons of nanosphere trimers (equilateral triangles, group D3 h), quadrumers (squares, group D4 h), and tetramers (tetrahedra, group Td). This study shows that the plasmons of these systems are composed of linear combinations of plasmons from each individual particle and may be classified into the irreducible representations corresponding to the point group to which each system belongs. This represents a step forward in understanding the underlying concepts behind the plasmon modes of multi-particle systems. The periodic systems that are examined in this thesis include a one-dimensional infinite nanosphere chain and two-dimensional hexagonal and square nanosphere arrays. The calculated plasmon energies are shown to agree very well with Finite Difference Time Domain calculations, a somewhat surprising result considering the quasistatic nature of plasmon hybridization. In contrast to other modeling methods, wherein a nanosystem's plasmon frequencies are calculated computationally or as the poles of a polarizability function, plasmon hybridization provides a physical picture of the plasmon modes in each system in analogy with molecular orbital theory and thus proves to be an essential tool in understanding the fundamental science behind the plasmonics of these systems.

Photonic crystals are artificial structures with a periodically varying refractive index. This property allows photonic crystals to control the propagation of photons, making them desirable components for novel photonic devices. Photonic crystals are also termed as "semiconductors of light", since they control the flow of electromagnetic radiation similar to the way electrons are excited in a semiconductor crystal. The scale of periodicity in the refractive index determines the frequency (or wavelength) of the electromagnetic waves that can be manipulated. This thesis presents a detailed analysis of photonic crystals at visible, x-ray, and terahertz frequencies. Self-assembly and spin-coating methods are used to fabricate colloidal photonic crystals at visible frequencies. Their dispersion characteristics are examined through theoretical as well as experimental studies. Based on their peculiar dispersion property called the superprism effect, a sensor that can detect small quantities of chemical substances is designed. A photonic crystal that can manipulate x-rays is fabricated by using crystals of a non-toxic plant virus as templates. Calculations show that these metallized three-dimensional crystals can find utility in x-ray optical systems. Terahertz photonic crystal slabs are fabricated by standard lithographic and etching techniques. In-plane superprism effect and out-of-plane guided resonances are studied by terahertz time-domain spectroscopy, and verified by numerical simulations.

Magnetic flux threading a single-walled carbon nanotube (SWNT) is predicted to influence its electronic structure through the Aharonov-Bohm (AB) effect, causing bandgap oscillations and absorption peaks splitting. In order to verify these predictions, near infrared (NIR) photoluminescence (PL) and visible-NIR absorption in the Voigt geometry were measured at room temperature in external magnetic field (B) up to 74 T. The used aqueous surfactant solubilized SWNT samples show excitonic interband absorption peaks coming from a range of nanotube chiralities present in the sample. At fields B > 30 T, PL peaks showed red shifts and changes in peak widths. Magneto-PL spectra were successfully simulated, demonstrating that the observed spectral changes can be understood in terms of magnetic alignment of SWNTs (due to their predicted anisotropy magnetic properties) and B dependent changes of the bandgap due to the AB effect. By using the measured B-induced nanotube alignment and the measured average length of nanotubes in the sample, we estimated SWNT magnetic anisotropy to be 1.4 x 10-5 emu/mol, consistent with theoretical predictions. At B > 55 T, clear absorption peak splittings were observed, with splitting rates of 1 meV/T in good agreement with theoretical predictions. Recent theory predicts a dark singlet exciton state (below the only bright singlet state) which brightens as B is applied. Our observation of two bright excitons at high B demonstrates that magnetic field is indeed capable of brightening dark excitons.

A novel methodology based on the scanning confocal microscope is presented which enables a general solution of the depth resolution problem in holography and other coherent imaging schemes. The method does not depend on a priori information about the object. Background and historical perspective are provided, as well as some review of the Rayleigh-Sommerfeld diffraction formulation and other pertinent physical optics topics. Some signal processing and numerical methods specific to the simulation of the propagation and diffraction of light are presented and applied. Holograms were simulated, providing the initial test bed for these concepts. Collimated confocal reconstruction of holograms, is discussed and demonstrated on a simulated hologram. The apertured scanning version is then discussed, and shown to have depth and lateral discrimination properties similar to those of the scanning confocal microscope. The first application of confocal processing to real holographic data is presented, demonstrating the expected depth discrimination and contrast improvement. Frequency diverse microwave holograms were used as input, and therefore background and characterization of that system are provided. In addition, some improvements in computational reconstruction of spherical shell microwave holograms are presented. As a demonstration for apertured scanning confocal hologram reconstruction, data from a typical microwave experiment was used as input. The experiment, using a 1/16 scale tank model, involved a scan of a full 360 degrees, and frequency diversity from 10 to 26 GHz. The results of confocal processing clearly demonstrate the desired effects of improved depth discrimination and contrast over conventional reconstruction. Details on the top of the tank become visible when strong returns from below the plane of interest, which are prominent in conventional reconstruction, are removed by the depth discrimination effect associated with the confocal arrangement. By demonstrating computational implementation of the concepts associated with the confocal microscope, opportunities are provided for imaging in many regimes where lenses and/or mirrors of high quality are not available. Extension of confocal processing to these systems is briefly discussed. Also, many opportunities to apply recent advances in scanning confocal microscopy are recognized, which may be implemented computationally. These include edge traversal and detection, automatic refocusing, and super-resolving methods.

Very short wavelength lasers have many potential scientific and technological applications. A practical extreme ultraviolet (XUV) laser system has been developed using the Xe Auger laser at 109 nm. This system is the first XUV laser system pumped by a standard, commercially available, Nd:YAG laser system at a high repetition rate. The Xe laser is pumped by the soft x-rays generated by a laser-produced plasma. A grazing incidence, traveling-wave pumping geometry is used to reduce the pump energy required to achieve saturated energy outputs. A total equivalent small signal gain of exp(25) has been achieved with a 20 cm long gain region. The maximum output energy of this system is about 1 $\mu$J. The extension of the laser-produced plasma pumping technique to extremely short wavelength lasers will require very high power, ultrafast laser pulses in order to produce sufficient upper state densities for gain within the short lifetime of the excited state. To this end, we have studied a new ultrashort laser pulse amplifier based on the broad bandwidth XeF(C $\to$ A) excimer transition that is capable of directly amplifying pulses as short as 10 fs duration and has high energy storage capability. Construction of a tunable, blue-green, subpicosecond source of laser pulses for injection into the XeF(C $\to$ A) excimer amplifier is described. Gain characteristics of the XeF(C $\to$ A) excimer amplifier were investigated for several pulse lengths. Saturation energy densities of 50 mJ/cm$\sp2$ and 80 mJ/cm$\sp2$ were measured for injected laser pulse durations of 250 fs and $\sim$100 ps, respectively. A gain bandwidth of 60 nm was observed. Using an optimized unstable resonator design, the laser amplifier produced 275 mJ pulses with a duration of 250 fs, and a 2.5 times diffraction limited beam quality, making the XeF(C $\to$ A) excimer amplifier the first compact laser system in the visible spectral region to reach peak powers of the terawatt level.

It is possible to enhance the image of an object without any image processing by optimal illumination. This thesis first reviews some basic results in radiometry and image formation. Then it proposes a method for optimally illuminating a convex polyhedral object made of k Lambertian faces by a set of directional light beams according to an edge detection criterion. The illumination of the scene is considered to be optimal when the edges of the corresponding image have the best chance of being detected simultaneously. This can be expressed as a maximin optimization problem on a set of values characterizing the edges. The solution to this problem is derived in the case of a convex prism lighted by a single directional light beam and the results of an experiment corresponding to this case are given.

Thin films of lithium niobate on various oriented sapphire substrates were fabricated by the rf sputtering method. Polarized He-Ne laser light with a wavelength of 6328 A was successfully coupled into the optical waveguides by a rutile prism coupler. A description of the prism coupler used for this research is given. The guided modes excited by the prism coupler were observed and used to examine the optical properties of the waveguide. The refractive indices and thicknesses of various samples were calculated and tabulated. The birefringence observed in the films and x-ray diffraction studies have confirmed the polycrystalline nature of the films. The attenuation of the light propagating in various (zeroth- to second-order) waveguide modes was determined to be in the range of 1.1 to 1.3 $\pm$ 0.1 dB/cm.

Spectral and temporal characteristics of a subpicosecond KrF excimer laser are determined with the use of a one meter spectrometer, a single shot intensity autocorrelator, and a single shot phase sensitive autocorrelator. Spectral analysis is shown to be a simple and sensitive method for aligning the laser system. Experimental results and model calculations show that the center of the laser spectrum is influenced by self phase modulation. Near the edge of the amplifier gain bandwidth, the spectrum is also influenced by the vibrational levels of the KrF upper state. To support the spectral analysis, temporal measurements are performed with single shot autocorrelators. Using a single shot autocorrelator based on three photon fluorescence of XeF, the pulse width was measure at 477 fs. To determine the frequency chirp of the laser, a single shot phase sensitive autocorrelator for ultraviolet lasers was designed, and preliminary tests were performed.