Upconversion coefficients in a new high-concentration erbium-doped tellurite glass were obtained a schematic study of experiments and modeling. The upconversion coefficient for ⁴I₁₃/₂ + ⁴I₁₃/₂ → ⁴I₉/₂ + ⁴I₁₅/₂ is found to be 2.74 x 10⁻¹⁸ cm³/s and for ⁴I₁₁/₂ + ⁴I₁₁/₂ → ⁴I₁₅/₂ + ²F₇/₂ is 1.09 x 10⁻¹⁸ cm³/s. The performance of high concentration Er³⁺+-Yb³⁺ -codoped phosphate fiber amplifiers and the performance of a high-power Er³⁺-Yb³⁺-codoped phosphate fiber laser were presented. From a 3.6cm-long fiber, 18 dB internal gain i.e. 5 dB/cm, for small signal input at 1535 nm, was achieved. With a cleaved facet as the output mirror, a fiber laser has been demonstrated from the same fiber with an output power of 33.8 mW at 1549.92 nm. A high slope efficiency of 40.2% was observed. Modeling results of gain and noise figure of four phosphate EDFAs with different lengths were presented with previous measured results. 34% erbium ions were found to be paired in our 3.5wt% erbium-doped phosphate fiber amplifiers. The onset of erbium concentration for pair induced quenching is suggested to be around 3wt% in phosphate fiber amplifiers.

<p> An optomechanical system consists of an optical cavity coupled to a mechanical oscillator. The system used for this work was a silica microsphere. In a silica microsphere, the optical cavity is formed by light that is confined by total internal reflection while circulating around the equator of the sphere. The mechanical oscillator is the mechanical breathing motion of the sphere itself. The optical cavity and mechanical oscillator are coupled by radiation pressure and by the mechanical oscillator physically changing the length of the optical cavity. </p><p> The optomechanical analog to electromagnetically induced transparency (EIT), known as optomechanically induced transparency (OMIT), has previously been studied in its steady state. One topic of this dissertation is an experimental study of OMIT in the time domain. The results of these experimental demonstrations continue comparisons between EIT and OMIT, while also building a foundation for optomechanical light storage. </p><p> In OMIT, an off-resonance control laser controls the interaction between on-resonance light and the mechanical oscillator. Optomechanical light storage makes use of this arrangement to store an optical signal as a mechanical excitation, which is then retrieved at a later time as an optical signal. This is done by using two temporally separated off-resonance control laser pulses. This technique is extremely flexible in frequency and displays a storage lifetime on the order of microseconds. </p><p> Use of optomechanical systems for quantum mechanical applications is hindered by the thermal background noise of the mechanical oscillator. Addressing this issue by first cooling the mechanical oscillator is costly and fraught with difficulties. The final topic presented in this dissertation deals with this issue through the use of an optomechanical dark mode. Two optical modes can interact with the same mechanical mode. The dark mode is a state that couples the two optical modes but is decoupled from the mechanical oscillator. </p><p> While our specific optomechanical system is limited by its somewhat modest optomechanical cooperativity, this conversion process can, in principle, preserve the quantum state of the signal, even at room temperature, opening the possibility for this technique to be applied in quantum information processing.</p>

This dissertation presents investigations of fundamental optical nonlinearities in semi-conductor microstructures. Two distinct effects are studied. In the first part the excitonic optical Stark effect in InGaAs and GaAs multiple quantum-well structures is investigated by means of pump-probe spectroscopy. For nonresonant excitation below the excitonic transition the direction of the shift of the resonance depends on the polarization of the pump and probe pulses. In particular, for anti-circular polarization a surprising red-shift is observed. For resonant excitation, induced absorption energetically above and below the exciton transition and bleaching of the resonance is found. Experiments using both resonant and nonresonant excitation reveal the importance of bound and unbound two-exciton states in absorption changes of the 1s heavy-hole exciton resonance. It is found that higher-order Coulomb contributions determine the intensity as well as the time dependence of the differential excitonic absorption. In addition, the influence of light-hole excitons is analyzed. It is shown that the direction of the optical Stark shift for nonresonant excitation depends also sensitively on the heavy-hole to light-hole splitting and the detuning of the pump pulse. For very high pump intensities and nonresonant excitation the absorption is split when a circularly polarized pump and a linearly polarized probe beam are used. For co-circular excitation traces of hyper-Raman gain are observed. In the second part of this dissertation, the nonlinear optical response of semiconductor microcavities in the nonperturbative regime is studied in resonant single-beam transmission and pump-probe experiments. In both types of experiment, a pronounced third transmission peak lying spectrally between the two normal modes is observed. Its dependence on the probe intensity, pump intensity, pump-probe delay, exciton-cavity detuning and pump detuning is investigated. For single-beam transmission, the energy of the third peak parallels the position of the cavity resonance. It is more pronounced for circularly polarized excitation and lasts longer than the two normal modes. For pump-probe experiments, the third peak increases with decreasing probe intensity and increasing pump intensity. Its energy is close to the low-energy side of the pump spectrum and virtually unaffected by the cavity-exciton detuning. The appearance of the third peak requires temporal overlap of pump and probe pulses. The origin of this complex nonlinearity is the quantum nature of light, which induces intraband polarizations in the presence of a coherent driving field and a finite carrier density. It is found that the coupling of the intraband polarizations via guided modes to the polarization of the fundamental longitudinal mode is responsible for the third transmission peak. A fully quantized theory reproduces the experimental observations.

This dissertation proposes and demonstrates an innovative technique for ultra-resolution data storage. An original idea that combines two near-field techniques, aperture probes and the solid immersion lens (SIL), is implemented through modeling, fabrication, testing, phase-change recording, and writing condition studies. In the modeling, a theory for illumination and signal detection is presented. The power transmission for different near-field transducers illuminated by a lens is calculated versus NA. In detection, the angular spectrum illustrates advantages of the combination aperture system. In addition, geometrical design considerations are discussed with the modeling. Nearly optimal designs for APSIL and Al aperture + SIL are presented for the illumination wavelength 488 rim. Fabrication techniques are developed for dielectric aperture + SIL, which is called APSIL, and Al aperture + SIL, respectively through modeling geometrical design. Both near-field transducers are tested by edge-scan experiments. Spot size and optical efficiency from the APSIL system are evaluated. APSIL is evaluated for high-density recording on a phase-change medium. Minimum mark size and the modulation transfer function (MTF) are obtained experimentally. Control of writing conditions for an APSIL system are investigated with respect to polarization, axial focus position and transverse beam alignment. Our study shows that the APSIL system achieves much higher optical efficiency than aperture probe systems as well as exhibits better resolution than SIL systems.

Non-Uniform-Rational-B-Spline (NURBS) surfaces were investigated as a tool for creating an incoherent uniform circular illuminance distribution on a target plane. Specifically, a superposition solution, employing faceted reflective surfaces was explored. The primary shape of the facets investigated was square, in spherical polar coordinates, mainly due to tiling concerns. An optimization procedure was the primary method for determining the NURBS variables for facet surfaces. For the case of a single square-facet that creates a uniform circular-illuminance distribution, a perfect solution using aim-ray defects proved difficult at best. However, the use of flux tubes in evaluating the illuminance yielded a highly uniform distribution with a very nearly circular shape. Superposition surface-point interpolation NURBS surfaces, constructed with this type of facet, were found to provide an excellent solution to the overall problem. Solutions of this type were shown to be more efficient than a standard algorithmic approach. NURBS surfaces provided excellent boundary control, and while often non-critical in single-aperture systems, boundary control was found to be very important for faceted systems. The techniques developed for creating uniform illuminance distributions with shapes different from the facet aperture were also applied to other problems: such as a square-facet to arcuate-illuminance pattern, and a circular-facet to a square-illuminance pattern.

In order to better facilitate the use of aspheres in optical design, metrology systems must become independent from the asphere under test. This requires testing in a non-null sense. Large aspheric departures and steep wavefront slopes must be detected by the metrology instrument. Sub-Nyquist interferometry (SNI) is one such method which has been shown to reconstruct large wavefront departures. Large departures generate high spatial frequency fringes, which must be detected by the interferometer. This requires the use of a sparse array sensor to capture the high spatial frequency fringe data. A custom detector for this purpose has been developed and tested over spatial frequencies up to 400 cycles/mm. Testing in a non-null manner causes the test and reference rays in the interferometer to follow different optical paths through the system. The errors generated by this difference are test part dependent and must be calibrated independently for each test piece. Lens design software can be used to perform reverse optimization of the interferometer and data. This process requires an accurate interferometer model and is sensitive to the relative weighting of the various merit function targets. An iterative reverse optimization process has been developed which eliminates the weighting sensitivity and improves the optimization efficiency. The implementation of reverse optimization in turn generates constraints on the interferometer design. The class of aspheres to be tested also influences the system design. These factors lead to constraints on lens parameters, system apertures, and component verification considerations. A Mach-Zehnder interferometer is designed which satisfies the requirements and is used to build a transmitted wavefront SNI system. Experiments on several test parts were performed to verify the iterative reverse optimization process and to extend the use of SNI to non-rotationally symmetric aspheric wavefronts. Wedge angles were measured to within 1.5 arcseconds, radii of curvature to 0.1% and wavefront departures of up to 200λ were characterized to λ/6 PV and λ/47 rms. The reverse optimization process was shown to successfully remove up to 25 of induced aberration from an aspheric measurement. The results indicate potential for application of the iterative method and its associated design constraints to new interferometers for aspheric testing.

This dissertation derives and demonstrates a new approach to the design of wide-field interferometric telescopes. The first part of this dissertation is a tutorial on multiple aperture systems. Design basics such as PSF and OTF, fill factors, resolution, and temporal coherence are investigated. We show that the perfect image for a multiple aperture system is the sum of an image from each aperture and a set of fringes from each pair of apertures. Four example systems are designed by applying the derived design rules. The first system is a rotationally-symmetric Paul system that is then segmented to make a four-aperture system. The low-order design rules in this system are shown to be automatically satisfied. The second system is an array of four afocal telescopes that share a three-mirror combining telescope. Fold flats are used in the inner two arms to satisfy the requirement that the axial pathlengths should match. Linear piston errors are eliminated by forcing the beam configuration into the combiner to be a scaled version of the afocal array. The angles of the fold flats are chosen to eliminate any constant tilt errors. As a third example, the design of a beam combiner for the Large Binocular telescope is explored. By applying the design rules, coherent imaging with a 1 arcminute field of view is achieved with just three reflections. Linear defocus errors appear, but are minimized by bringing the beams to focus as closely together as possible. The sine condition is satisfied for the axial rays so that the linear piston errors are zero. As a fourth example, a space telescope design is presented that utilizes a flat gossamer mirror technology. The system would consist of a primary array of flats, a shared secondary mirror, and a tertiary array with one mirror corresponding to each of the primary flats. Each branch of the system consists of a primary flat, the shared secondary, and a tertiary that brings the beam to the correct image point. The position of the tertiary is chosen to eliminate axial pathlength errors. The RMS wavefront error is calculated as a function of the system parameters. This gives an efficient method for exploring design space for the gossamer systems. The performance of a system of five flats is explored in this way. A few specific five-flat systems are modeled with full interferometric raytraces, and the results show good agreement with the Strehl values predicted by calculation of the RMS wavefront errors. (Abstract shortened by UMI.)

Planar waveguide amplifiers and lasers were fabricated using Ag film ion exchange on Er³⁺/Yb³⁺ codoped phosphate glass. The performance of these amplifiers and lasers were studied and characterized. Silver film ion exchange process was thoroughly studied and a process suitable for fabrication of low loss waveguides on Er³⁺/Yb³⁺ codoped phosphate glass was developed. A transmission loss of 0.15 dB/cm was obtained in surface waveguides on phosphate glass. Planar waveguide amplifiers were fabricated on Er³⁺/Yb³⁺ codoped phosphate glass and characterized. A net gain of 7 dB in a sample of length 4.7 cm and gain/cm of 1.5 dB/cm were achieved. Single mode waveguide laser arrays pumped by single mode laser diodes were fabricated. Their performance was characterized in terms of the output power, spectrum of the laser, lasing wavelength dependence on the waveguide width and the relative intensity noise (RIN) of the laser. The tunability of the lasing wavelength to the desired wavelength, after waveguide fabrication, by annealing was demonstrated. A novel planar waveguide laser configuration for single-mode operation around 1550 nm using cost-effective multimode diode pumping was demonstrated. The laser was fabricated by Ag film ion exchange in a hybrid phosphate glass which has active and passive regions monolithically integrated in a single glass chip. Power of 54 mW at 1538 nm was measured from the single-mode output waveguide.

The subject of this dissertation is the implementation of Computed Tomographic Imaging Channeled Spectropolarimetry (CTICS) in the design and analysis of a short wave infrared (SWIR) system with a 54 x 46 spatial resolution and 70 band spectral resolution from 1.25-1.99 μm for the purpose of object identification and classification. It is the first of its kind to provide imaging spectropolarimetry with no moving parts and snapshot capability. This spectropolarimeter has applications in many fields, such as mining, military reconnaissance, biomedical imaging, and astronomy. First, motivations are provided for building this unique imaging spectropolarimeter by discussing the current applications of such systems, the drawbacks of previous designs, and a review of some the current systems being used. A review of basic concepts on imaging systems, linear algebra, and polarimetry is given as an introduction into the technical details of the design of the system that follow. First, designing the Computed Tomography Imaging Spectrometer (CTIS) and then the channeled spectropolarimetry components. The fusion of these two techniques create the CTICS. An assembled version of the SWIR CTIS is calibrated and reconstructions of various objects demonstrate the capabilities of this portion of the system. The polarimetry components are added and a discussion follows on the method used to extract the new data. Two systems, a polarization state generator (PSG) and rotating retarder fixed analyzer (RRFA) system are built to verify the CTICS accuracy. The final assembled system is presented and testing results are shown. Error analysis on various sources of noise is done. To conclude, a novel sub-Nyquist sampling technique is demonstrated and future work is suggested on a reconstruction technique that will streamline the postprocessing of the images.

A new instrument, the polarization phase-shifting point-diffraction interferometer (PPSPDI), is developed utilizing a birefringent pinhole plate. The interferometer uses polarization to separate the test and reference beams, interfering what begin as orthogonal polarization states. The instrument combines the robust nature of Linnik's original point-diffraction interferometer with the ability to phase-shift for interferogram analysis. The instrument is compact, simple to align, vibration insensitive and can phase-shift without moving parts or separate reference optics. This dissertation describes the theory, design, application and manufacturing considerations of the PPSPDI. The original PDI design is expanded to include polarization and phase-shifting. The discussion includes the properties of the birefringent material used as well as various fabrication methods used for creating the pinhole. A new model is developed to determine the quality of the diffracted reference wavefront from the pinhole as a function of pinhole size and aberrations of the test optic. The operation and performance of the interferometer are also presented along with a detailed error analysis and performance limits of the design.