Characterization of excimer lasers for application to lenslet array homogenizers.

We investigate the best method of characterizing high-divergence lasers, such as excimer lasers, to suppress fine-scale intensity nonuniformity that is due to coherence effects of lenslet homogenizers. We show by a detailed analysis of the lenslet homogenizer that, for highest accuracy, a direct measurement of the value of the autocorrelation function should be made at the separation p of the lenslet elements, identified as the critical spatial period. We show that the commonly used characterization of lasers by the 1/e(2) width of the angular divergence is not the most accurate test and may overstate or understate the effectiveness of a given laser.

Technetium-99m sestamibi scanning in multiple myeloma stem cell transplantation.

We report the use of technetium-99m sestamibi (MIBI) in a patient with multiple myeloma (MM) undergoing peripheral blood stem cell (PBSC) transplantation. MIBI is a radionuclide agent that is preferentially taken up by malignant tumors. Plain radiographs in a MM patient, taken prior to PBSC transplantation, showed a large right humeral lytic lesion that correlated with increased uptake of MIBI at the same location. MIBI uptake, demonstrating active MM bone disease, was also evident in areas which were normal on plain radiographs. Three months after PBSC transplant, the lytic lesion had healed by plain radiographs and repeat MIBI scan showed no uptake. MIBI scanning results have a positive correlation with plain radiographs, and more importantly, demonstrate active MM bone disease not yet detectable by plain radiographs. If MIBI proves more sensitive in the detection of MM bone disease than plain radiographs or bone scanning with traditional isotopes, it will have a significant role in the detection of early disease and in monitoring disease progression during and after therapy.

Translocation (12;15)(p13;q13) in a patient with relapsed acute myeloid leukemia.

We report a patient with a history of leukopenia who developed acute myeloid leukemia (AML) FAB M2 and was successfully treated with induction and consolidation chemotherapy. She relapsed 7 months after initial diagnosis. Peripheral blood cells at relapse showed a t(12;15)(p13;q13), which has not been previously described in de novo or relapsed AML.

Design of continuous surface-relief phase plates by surface-based simulated annealing to achieve control of focal-plane irradiance.

High-performance phase plates are of vital concern for controlling the far-field irradiance of laser-fusion systems. Several designs for solving this difficult problem have been reported in Optics Letters [e. g., S. N. Dixit et al., Opt. Lett. 19, 417 (1994)]. We report a surface-based form of simulated annealing that significantly improves the irradiance control while eliminating the high-scatter problems that have plagued other methods.

Technetium-99m Sestamibi Scanning Reflects Marrow Activity in a ß-Thalassemia Patient Treated with an Allogeneic Bone Marrow Transplant.

ß-thalassemia major is a disorder of globin synthesis, resulting in anemia and compensatory bone marrow hyperproliferation. Conventional imaging studies do not measure bone marrow activity reliably. We report on the use of technetium-99m sestamibi (MIBI) in a ß-thalassemia major patient treated with an allogeneic bone marrow transplant. Pre-transplant and early post-transplant MIBI scannings demonstrated generalized marrow uptake, reflecting marrow hyperproliferation. After full engraftment, post-transplant MIBI showed disappearance of abnormal uptake in the skeleton, indicating normalization of the marrow activity. MIBI scan may be used as a noninvasive measure of bone marrow proliferation that may guide hypertransfusion therapy in thalassemia patients.

Burkitt translocation (8;22)(q24;q11) in a patient with multiple myeloma.

The prevalence of chromosomal abnormalities in multiple myeloma (MM) has been difficult to detect by karyotyping primarily because of the low proliferative rate of malignant plasma cells. The reported incidences of abnormal karyotypes range from 24% to 63% in bone marrows obtained from MM patients, with the higher rates being seen in aggressive disease [1-8]. Detection of abnormal karyotypes in MM has been associated with a poor prognosis. We report a MM patient with an 8;22 Burkitt translocation, the first such reported case.

Distributed phase plates for super-Gaussian focal-plane irradiance profiles.

The design of phase plates based on a phase-retrieval algorithm has been shown to be successful in achieving high order super-Gaussian distributions in the far field; however, these phase plates exhibit wide-angle scattering losses due to phase discontinuities. We report that, by starting with a distributed phase plate that is a strictly continuous surface and using only a few cycles of a phase-retrieval algorithm, we have obtained good fourth-order super-Gaussian fit and lower scattering loss.

Adaptive optics for in-orbit aberration correction: spherical aberration feasibility study.

We investigate the feasibility of using an adaptive mirror for in-orbit aberration corrections. The advantage of an in situ aberration correction of optical components in the space environment is that the mirror shape can be adjusted in an iterative fashion until the best image is obtained. Using the actuator spacing, corresponding to one half of the Nyquist frequency, the Strehl ratio of the corrected wave front improves to 0.95 when the mirror is fabricated with 6.5 waves of spherical aberration. The Strehl ratio decreases to 0.86 when the number of actuators is reduced by a factor of 4, in a two-dimensional adaptive optics model.

Raman scattering in air: four-dimensional analysis.

Inertial confinement fusion requires propagation of high-intensity, pulse-shaped IR and UV laser beams through long air paths. Such beams are subject to energy losses and decreased beam quality as a result by stimulated rotational Raman scattering (SRRS). In this paper we describe how quantum fluctuations, stimulated Raman amplification, diffraction propagation, and optical aberrations interact during the propagation of short, high-power laser pulses using a four-dimensional (4-D) model of the optical beams and the medium. The 4-D model has been incorporated into a general optical-propagation computer program that allows the entire optical system to be modeled and that is implemented on high-end personal computers, workstations, and supercomputers. The numerical model is used to illustrate important phenomena in the evolution of the optical beams. In addition, the OMEGA Upgrade laser system is used as a design case to illustrate the various considerations for inertial confinement fusion laser design.

Physical optics modeling in soft-x-ray projection lithography.

We develop a diffraction-based tool that can predict the image quality in projection lithography systems. The effects of partial coherence and source variations and imaging defects in both the condenser and the camera optics can all be determined.

Polarization properties of planar dielectric waveguide gratings.

An experimental and theoretical study of polarization properties of planar dielectric waveguide gratings operating at general (oblique) inicidence is reported. The radiation modes coupled out by a surface-relief waveguide grating, when the incident light is not normal to the grating rulings, are linearly polarized for TE excitation and are elliptically polarized for TM excitation. The polarization states of the radiation modes are determined primarily by the polarization state of the principal guided wave in the grating region and by the propagation directions of the radiation modes with respect to the plane of the principal guided wave. Experimental data and numerical results based on three physical models are presented.

Beam propagation in gradient refractive-index media.

A generalized beam propagation method is described that uses the ABCD matrices to treat optical systems that have modest amounts of aberrations including gradient refractive-index elements. We can make calculations from any point in the near or far field to any other point by using appropriate numerical algorithms. The variation of the reduced length is discussed as a limitation to accuracy. The diffraction properties of a complex stigmatic system may be represented by those of an equivalent elementary system. This facilitates calculations using the standard diffraction operations for homogeneous media. The modified propagation technique replaces the large number of diffraction steps commonly used for the split-step solution of inhomogeneous media with one step for stigmatic media and in general no more than a few steps for aberrated media. Maxwell's fisheye lens is discussed in detail to show application of the method.

Rotationally symmetric construction optics for a waveguide focusing grating.

Waveguide grating couplers have been under study as a method of focusing laser diode radiation on the surface of an optical data storage device. In this letter, we describe a simple method of holographically constructing a waveguide grating coupler at visible wavelengths which may be used with collimated infrared laser radiation to form high numerical aperture, diffraction limited beams. The design method includes the necessary compensation aberrations to offset the effects of differences between construction and end-use wavelengths.

Zonal model of an adaptive mirror.

An approximate model of an adaptive optic element is presented which works well for components having many actuators. This zonal model is used to gain insight into the general behavior of systems that correct for high spatial frequency errors. The model is derived from the method of least squares, and considers the nonshift invariant properties of adaptive mirrors. It may be implemented with Fourier transform techniques and is, therefore, easy to program. The relationship between the zonal model and the simpler bandpass filter model of Harvey and Callahan is discussed.

Physical optics analysis of the focusing grating coupler.

Fourier optics and waveguide theory are used to develop a numerical procedure to calculate performance of the focusing chirped grating. This device is of interest in development of an integrated optical data head. The method considers diffraction, aberrations, nonuniform illumination, and the effect of the grating boundary.

Focusing grating coupler design method using holographic optical elements.

The focusing grating coupler (FGC) can be constructed using holographic techniques. Due to the wavelength scaling between the construction of the FGC and its final end-use operation, aberrations exist in the final spot. A design method is demonstrated that can be used to model the FGC as a holographic optical element. The method also includes techniques to eliminate the aberrations due to the wavelength scaling.

Subaperture testing of aspheres with annular zones.

A subaperture configuration to test aspheric optical components or systems has been developed. The aperture is divided into annular subaperture regions, and an interferometer is refocused for each region to reduce the fringe density. The method is suited to phase-measuring interferometry and may be used with standard interferogram reduction software. The theoretical basis for the method, requirements for the number of annular zones, sensitivity to the selection of the number of polynomials, and tolerances for centration and radius are described. Numerical and experimental validations of the algorithm are described. The method may eliminate the need to use null lenses for measuring some aspheres at the center of curvature.

Interferometric characterization of full spheres: data reduction techniques.

This paper describes numerical procedures for data reduction of full spheres from interferometric data taken at various positions around the surface of the sphere. The technique allows the use of practical f/No. optics, incomplete coverage or overlap of the interferograms, and differences in optical alignment of each interferogram.

Increased accuracy and speed of absorption cytometric DNA measurements by automatic corrections for nuclear darkness.

We have developed a method of calculating the average local absorbance (ALA) of a nucleus from the integrated nuclear absorbance and area. One can use the ALA, along with nuclear areas measured at different point absorbance thresholds, to determine whether a nucleus is stained too lightly or too darkly for accurate absorption measurements; this allows selection of an optimal light wavelength for the performance of these measurements. The ALA can also be used for automatic and instantaneous correction of integrated absorbance values from darkly stained cells. This allows the rapid measurement of the integrated absorbances of a large number of nuclei that are heterogeneous in stain intensity. Coefficients of variation of approximately 3% are obtained for the integrated absorbances of nuclei of nontransformed G0/G1 cells. This correction method can be applied with any image densitometer that generates both integrated absorbance and area values.