In order to increase sky coverage, adaptive optics (AO) systems for large telescopes will require laser systems to provide artificial reference beacons. The most prominent method for creating an artificial beacon is to project laser light tuned to the 589nm, D2 line of sodium onto the mesospheric sodium atoms at an altitude of 90km. When correcting with AO, the best wavefront measurements are obtained when the image of the sodium beacon is as bright and sharp as possible. Blurring occurs due to spot elongation, as a result of sub-aperture displacement from the projector axis, and from diffraction and seeing effects on the projected beam. Mounting the projector in the center of the telescope minimizes the effect of elongation. Simulations were conducted that show that matching the beam waist to ∼2 times the atmospheric turbulence parameter r₀ minimizes the beacon size. For r₀ = 15cm and a 48cm projector, calculations show the optimum projected waist is 29cm. A prototype projector has been built and operated. Recent experiments have shown that this projector is capable of producing 0.75arcsec beacons under good seeing. In addition, spot elongation of 0.5arcsec was observed corresponding to a sodium layer thickness of 10km. The first experimental evidence for optical pumping in the mesospheric layer were obtained. They show a non-thermal profile for the sodium hyperfine structure (3.5:1 line ratio as opposed to 5:3) when projecting circularly polarized light. This profile indicates that the maximum return per watt is obtained by pumping the F = 2 level with a narrow bandwidth compared with pumping both F = 2 and F = 1 with a broad bandwidth. In addition, evidence shows a 30% increase in beacon brightness when pumping the sodium layer with circularly polarized light over linear. A projector for the 6.5m MMT conversion has been designed based on experience gained with the prototype. Analysis of the Strehl reduction due to wavefront reconstruction error shows a reduction in Strehl of < 1% for the optimal operating parameters at the MMT. This less than the fundamental limit of 0.79 for focus anisoplanatism.

Vicarious calibration methods have been developed to calibrate radiometric sensors in-flight. One such method, the irradiance-based method, requires the measurement of the diffuse-to-global (diffuse-to-total) irradiance ratio. Diffuse/global irradiance measurements may also be used to deduce atmospheric descriptors and provide a comparison with atmospheric modeling predictions. I describe the design, construction, calibration, and application of a spectral diffuse/global irradiance meter that can accomplish these objectives in this dissertation. I develop general integrating sphere theory, modeling methods, and describe the resultant computer model. The model results agreed with theory to better than 1% for a simple unbaffled integrating sphere. I applied the model to design an interior baffled integrating sphere-based cosine collector. I developed a method of tolerating the thermal expansion of Spectralon® and the collector was constructed. Measurements of the collector angular response agreed with the model predictions to better than 4% for input zenith angles from 0° to 70°. The resulting instrument is automated and collects diffuse and global irradiance from 300 nm to 1100 nm. It has a nominal 12 nm full-width at half-maximum bandpass and has a minimum sampling interval of 1 nm. I estimate the uncertainty of the measurements to be 3.2%. The largest contributor to the total uncertainty is the measurement uncertainty of the diffuse irradiance at 2.5%. The instrument was used in a field experiment. Optical depths derived from the diffuse/global irradiance measurements agreed with those derived from a solar radiometer to within 0.008. Diffuse-to-global irradiance measurements made by the instrument were compared with an independent method and found to generally agree within 6%. The measurements were consistently lower than radiative transfer modeling estimates. Top of the atmosphere relative radiances computed from the two independent diffuse-to-global irradiance data sets generally agreed to better than the 2.9% uncertainty associated with the diffuse/global irradiance meter data set. The relative radiances of the diffuse/global data set collected with the instrument were within the 4.9% uncertainty estimate of the reflectance-based method.

Powerful lasers are needed to generate artificial guide stars for astronomical adaptive optics. Continuous wave (CW) lasers yield the most efficient excitation of the D2 line in the mesopheric sodium layer. Data is presented from early systems which used commercially available CW dye lasers. Building on these results, a dye laser was designed and constructed which incorporates a sodium Faraday filter (SFF) to select and lock the laser frequency to the peak of the D2 sodium resonance. This laser was the first ring dye laser made using an intra-cavity SFF, and also the first incorporating a SFF to produce a significant amount of power in a single longitudinal mode. A major part of this thesis concerns the design and construction of the SFF. The theory of operation is developed and then used to design a SFF with a high throughput at the D2 line of sodium. The two main elements of a SFF are a sodium cell and a magnet. The design and construction of these two elements is discussed in detail. The design and construction of a wavefront sensor for the Multiple Mirror Telescope's unique geometry is presented. This wavefront sensor and a CW dye laser were used to generate the first astronomical images sharpened by an adaptive optics system incorporating a sodium laser guide star.

Amplification of low-light-level optical images is important for extending the range of lidar systems that image and detect objects in the atmosphere and underwater. The use of range-gating to produce images of particular range bins is also important in minimizing the image degradation due to light that is scattered backward from aerosols, smoke, or water along the imaging path. For practical lidar systems that must be operated within sight of unprotected observers, eye safety is of the utmost importance. This dissertation describes a new type of eye-safe, range-gated lidar sensing element based on Solid-state Raman Image Amplification (SSRIA) in a solid-state optical crystal. SSRIA can amplify low-level images in the eye-safe infrared at 1.556 μm with gains up to 106 with the addition of only quantum-limited noise. The high gains from SSRIA can compensate for low quantum efficiency detectors and can reduce the need for detector cooling. The range-gate of SSRIA is controlled by the pulsewidth of the pump laser and can be as short as 30-100 cm, using pump pulses of 2-6.7 nsec FWHM. A rate equation theoretical model is derived to help in the design of short pulsed Raman lasers. A theoretical model for the quantum noise properties of SSRIA is presented. SSRIA results in higher SNR images throughout a broad range of incident light levels, in contrast to the increasing noise factor with reduced gain in image intensified CCD's. A theoretical framework for the optical resolution of SSRIA is presented and it is shown that SSRIA can produce higher resolution than ICCD's. SSRIA is also superior in rejecting unwanted sunlight background, further increasing image SNR. Lastly, SSRIA can be combined with optical pre-filtering to perform optical image processing functions such as high-pass filtering and automatic target detection/recognition. The application of this technology to underwater imaging, called Marine Raman Image Amplification (MARIA) is also discussed. MARIA operates at a wavelength of 563 nm, which passes most efficiently through coastal ocean waters. The imaging resolution of MARIA in the marine environment can be superior to images produced by laser line scan or standard range-gated imaging systems.

A complete Stokes imaging spectropolarimeter has been developed based on the principles of computed-tomography, spectrometry and polarimetry. The Computed-Tomography Imaging SpectroPolarimeter (CTISP) is a polarization extension to the Computed Tomography Imaging Spectrometer (CTIS)¹. Imaging spectrometers estimate the object cube (x,y, λ), whose smallest subdivision is a voxel, while Stokes imaging spectrometers estimate four Stokes object cubes (x,y, Sp(λ); p = 0,1,2,3), one for each Stokes parameter. CTISP uses a two-dimensional disperser to diffract the image in the field stop into a 5-by-5 array of diffraction orders. As in computed tomography, each focal plane array (FPA) pixel effectively integrates a different path through the object cube, and when all pixels are recorded, a significant portion of the object cube's information is obtained. The frequency space representation of the object cube, however, indicates that two conical regions of information are not recorded, thereby limiting the reconstruction accuracy. CTISP scans only in the polarization domain (not spectral or spatial domains), acquiring four FPA frames, one behind each of the four polarization analyzers. Currently, CTISP's resolution is 33 by 33 spatially over a 3.5 degrees full angle field of view with 16 spectral bands of 20nm width covering 440nm-740nm. CTISP acquisition is modeled using the linear imaging equation gₐ=Hₐfₐ+ξₐ, which is inverted using the iterative expectation-maximization algorithm to solve for fₐ, the object cube as seen through analyzer a. The recorded diffraction images gₐ and the empirically determined calibration matrices Hₐ, are each acquired using analyzer a. The nth voxel reconstruction result is extracted from each of the four fₐ vectors to form a four element vector f(n) which is then multiplied by the inverse of the voxel characteristic matrix W(n) to obtain the estimate of the Stokes vector S(n). W(n) is derived from the four Hₐ matrices. A fully computer-controlled calibration facility and a suite of programs are used to calibrate CTISP. CTISP was validated using synthetically generated and real objects. Spectral agreement is consistent with CTIS, while Stokes parameter polarization errors were typically 0.04-0.07 for this instrument. Errors are most significant at the spectral limits of CTISP. An object dependent correction reduces these errors to below one percent.

Vertical scanning interferometers are routinely used for the measurement of optical fiber connectors. There are increasing needs for measurements of such items as machined surfaces, contact lenses, paint texture, cell structure, and integrated circuit devices, to name a few. These structures have too much depth, or are too rough, to measure with standard interferometry methods. Phase-measurement interferometry methods are limited to surfaces that do not have any discontinuities larger than one quarter of the operating wavelength. On the other hand, vertical scanning interferometers can be very effective, even though they have low height resolution compared to that of phase-measurement interferometers. Improving the height resolution of vertical scanning interferometers from the point of hardware improvement and signal processing has been one of the major research interests in the surface metrology area. This work provides a new algorithm, which called here "PSI on the Fly" technique, as a solution for improving height resolution of vertical scanning interferometers. This dissertation begins with a review of white-light interference microscopes. The height and lateral resolutions are derived based on scalar diffraction theory. Next, various well-established. algorithms for finding a topographic map of the small object surface are discussed. The work proceeds with a discussion of the phase change upon reflection and its influence on the coherence envelope. Then phase measurement interferometry methods are reviewed. The emphasis is in errors in phase measurement resulting from using a white light source instead of a monochromatic light source as in the usual case. The following chapter describes and examines an often-observed artifact of vertical-scanning interferometry when applied to step heights. The artifact is called "bat wings" because of its appearance. The physical cause of the "bat wings" artifact is discussed through a diffraction model. The next chapter proposes an improved vertical-scanning interferometry algorithm. The method, called here "PSI on the Fly" technique, has been developed by combining regular vertical-scanning interferometry and a monochromatic phase-shifting interferometry technique. The PSI on the Fly technique improves the surface height resolution of vertical scanning interferometry to that of a phase-shifting interferometry measurement. In addition to the resolution improvement, the algorithm also successfully removes the "bat wings" artifact.

The devices using Electro-optic (EO) polymers has been demonstrated for high-speed modulators and switching because of its low dispersion, coating quality, inexpensive process. EO polymers itself has been progressing since their first invention some two decades ago, and simultaneously devices using the EO polymers have been demonstrated, corresponding to want from commercial communication system. Since the middle of ninety, active devices have been realized because to fabricate all polymeric waveguide structure in EO polymers has been realized with help of costly dry etching system. All polymeric waveguide still suffer from (1) low optical throughput due to coupling losses; (2) high intrinsic optical loss in EO polymers; and (3) optical-waveguiding instability due to photochemical reaction in EO polymers. Therefore, inexpensive process to solve these problems is needed when the fabricated devices is used in the commercial communication system. In this study, I mention theoretical backgrounds, properties, and then process for device fabrication to solve these precious all polymeric approaches.

The design and testing of an ocular Shack-Hartmann aberrometer is presented. The aberrometer objectively measures optical aberrations in the human eye in vivo. The sensor was successfully tested for measurements of refractive error (sphere and cylinder) and spherical aberration. Vignetting limits the measurement range of the wavefront to a range of -10 D to +15 D. Large refractive errors and decentration of the measurement induce aberrations in the test wavefront. Analytical tools to correct for these systematic errors were developed. A clinical study was conducted assessing visual performance in 158 eyes of 89 subjects before and after LARK refractive surgery. The main results of the study were that refractive surgery corrects refractive errors very accurately. A slight regression in refraction during the 12 months after surgery was noted. Measurements of ocular aberrations using the Shack-Hartmann aberrometer revealed that refractive surgery introduced large amounts of higher order aberrations, mainly spherical aberration and coma. The amount of aberrations changed significantly during the 12 months wound healing period. The dark adapted pupil diameter of the eye increased significantly during the first 6 months after surgery. The changes in ocular aberrations and pupil diameter were correlated to changes in contrast sensitivity in the human eye. The analysis of corneal topography showed that while the anterior corneal curvature changed due to surgery, we also saw a change in the posterior corneal curvature as a biomechanical response to surgery. A Customized Eye Model was designed and tested based on the clinical measurements. The model used conic surfaces and modeled defocus and spherical aberration. This computer eye model was then used in optical lens design software to calculate an optimal Customized Ablation Pattern for individual eyes.

A high contrast, low intensity GaAlInAs/AlInAs multiple quantum well asymmetric Fabry-Perot reflection modulator for operation at 1.3 μm has been demonstrated. The reflection modulator takes advantage of the large absorptive and refractive nonlinearities associated with saturating the heavy-hole exciton resonance. We achieve an on/off contrast ratio in excess of 1000:1 (30 dB) and an insertion loss of 2.2 dB at a pump intensity of 30 kW/cm², corresponding to a carrier density of 4.5 x 10¹⁷ cm⁻³ The modulator was demonstrated to have a large operating bandwidth, achieving an on/off contrast ratio of greater than 100:1 over a 5 nm optical band. The operating speed of the modulator was measured and found to approach 1 GHz.

Research has been done for the calibration of a thermal infrared imaging system for the measurement of transmission line conductor sample emissivities. The spectral response of the imaging system was from 8 to 12 micrometers. A laboratory set-up was designed and built for this analysis. The laboratory equipment consisted of a FLIR 1000a thermal infrared imaging system, a stainless steel black-body source with dual emissivity front surface coatings, an Elexor Industries PL1000 data acquisition and control system, and an IBM personal computer AT with imaging board and imaging software. The emissivities of the conductor samples were obtained through the analysis of thermal infrared images of each conductor with a blackbody cavity and low emissivity source simultaneously imaged as references. This analysis gave statistical mean grey levels for each conductor sample and references. From these mean grey levels the emissivity of the conductor samples were computed. Nine transmission line conductor sample emissivities where measured to an average accuracy of 17.5%. The emissivities ranged from .451 to .959.