Primary Aberration Research Articles

Primary aberrations in focused radially polarized vortex beams

We study the effect of primary aberrations on the 3-D polarization of the electric field in a focused lowest order radially polarized beam. A full vector diffraction treatment of the focused beams is used. Attention is given to the effects of primary spherical, astigmatic, and comatic aberrations on the local polarization, Strehl ratio, and aberration induced degradation of the longitudinal field at focus.

Structural design of cemented triplets by genetic algorithm

We present an implementation of a genetic algorithm in the structural design of cemented triplets according to a prespecified set of Gaussian characteristics and primary aberration targets. The approach is directed toward obtaining a suite of promising solutions allowing some floating of the primary aberration targets. This method obviates the need for any heuristic preselection of glasses for the three elements of the triplet. Searches for optimal solutions are conducted in the total configu- ration space of the degrees of freedom, consisting of continuous vari- ables like shape factor and power distributions, and discrete variables like available glass types. The role of genetic diversity in the evolving population on convergence of the optimization runs has been investi- gated, and, accordingly suitable modifications are incorporated in the basic genetic algorithm to eliminate undue stagnation and premature convergence problems. Some illustrative examples are given. © 2004

Outline of an ultracorrector compensating for all primary chromatic and geometrical aberrations of charged-particle lenses

A novel ultracorrector is outlined which compensates for the primary and secondary first-order chromatic aberrations and all third-order geometrical aberrations of electron optical systems with a straight axis. Owing to the imposed symmetry conditions on the fields and the paraxial fundamental rays, the corrector does not introduce aberrations with 2-fold symmetry. The chromatic aberrations are corrected by means of crossed electric magnetic quadrupoles while the third-order geometrical aberrations are eliminated by octopoles. By placing these elements at distinct positions within the corrector, it is possible to successively eliminate the third-order aberrations in such a way that each subsequent correction does not affect the aberrations corrected in the preceding correction steps.

Hilda Gertrude Kingslake/Rudolf Kingslake

Hilda Gertrude Kingslake/Rudolf Kingslake

Outline of an Ultracorrector Compensating for all Primary Chromatic and Geometrical Aberrations of Charged-Particle Lenses

A novel ultracorrector is outlined which compensates for the primary and secondary first-order chromatic aberrations and all third-order geometrical aberrations of electron optical systems with a straight axis. Owing to the imposed symmetry conditions on the fields and the paraxial fundamental rays, the corrector does not introduce aberrations with 2-fold symmetry. The chromatic aberrations are corrected by means of crossed electric magnetic quadrupoles while the third-order geometrical aberrations are eliminated by octopoles. By placing these elements at distinct positions within the corrector, it is possible to successively eliminate the third-order aberrations in such a way that each subsequent correction does not affect the aberrations corrected in the preceding correction steps.

Detection of chromosomal aberrations in prostate cancer by fluorescence in situ hybridization (FISH).

Fluorescence in situ hybridization (FISH) is a powerful tool for quantitative analysis of chromosomes and genes and can be applied in a variety of specimens, including cell cultures, isolated nuclei from fresh and fixed tissues, and histological tissue sections. For detection of numerical chromosome aberrations, we examined prostatic cancer samples at our department. In addition, we also observed primary and secondary aberrations taking part in the initiation and progression of tumours. FISH using chromosome-specific alpha-satellite DNA probes for chromosomes 7, 8, 9, 10, 17, X and Y was performed on 19 prostatic cancer and 19 benign prostatic hyperplasia (BPH) samples obtained from transurethral resection (TUR) and archival paraffin-embedded blocks. Numerical aberrations were observed in 41% of the tumours studied. A range of aberrant copy numbers of chromosome 9 (68%), 7 (63%), 8 (58%), 17 (37%), Y (32%) and 10 (26%) was observed. We did not observe significant aberrations in BPH samples. In prostate cancer patients, chromosomes 7 (47%), 8 (58%) and 9 (63%) were monosomic by FISH. Monosomy 8 and 9 were significant differences (p>0.05) between prostate cancer and BPH patients. FISH analysis could be observed an one of strongest methods of analysis in detecting numerical aberrations of individual chromosomes with application to paraffin-block samples, metaphase and, interphase nuclei. To our knowledge, this analysis is firstly studied in Turkish patients. Therefore, results of this analysis may be important for Turkish patients.

Optical systems under broad-band illumination: Analysis based on a wigner distribution function approach

The irradiance produced by an optical imaging system suffering from aberrations under broad-band illumination is analysed in the phase-space domain of the Wigner distribution function associated with a modified one-dimensional pupil aperture. To this end, a coordinate transformation is employed in such a way that the varying irradiance along different paths in the image space can be derived from different slices of the Wigner distribution function, which involve both the defocus distance and the dispersion properties of the optical system. The method is illustrated by comparing the axial irradiance distribution for different primary aberrations. Also, the irradiance along parabolic paths is obtained in order to analyse the coma effect.

Primary spherical aberration in two-color (two-photon) excitation fluorescence microscopy with two confocal excitation beams.

We study the effects of primary spherical aberration on the three-dimensional point spread function (PSF) of the two-color (two-photon) excitation (2CE) (2PE) fluorescence microscope with two confocal excitation beams that are separated by an angle theta. The two excitation wavelengths lambda1 and lambda2 are related to the single-photon excitation wavelength lambda(e) by: 1/lambda(e) = 1/lambda1 + 1/lambda2. The general case is considered where both focused beams independently suffer from spherical aberration. For theta = 0, pi/2, and pi, the resulting deterioration of the PSF structure is evaluated for different values of the spherical aberration coefficients via the Linfoot's criteria of fidelity, structural content, and correlation quality. The corresponding degradation of the peak 2CE fluorescence intensity is also determined. Our findings are compared with that of the 2PE fluorescence (lambda1 = lambda2) under the same aberration conditions. We found that the 2CE microscope is more robust against spherical aberration than its 2PE counterpart, with the pi/2 configuration providing the clearest advantage. The prospect of aberration correction in the two-beam 2CE microscope is also discussed.

Measurement of refractive errors in young myopes using the COAS Shack-Hartmann aberrometer.

To evaluate the Complete Ophthalmic Analysis System (COAS; WaveFront Science) for accuracy, repeatability, and instrument myopia when measuring myopic refractive errors. We measured the refractive errors of 20 myopic subjects (+0.25 to -10 D sphere; 0 to -1.75 D cylinder) with a COAS, a phoropter, and a Nidek ARK-2000 autorefractor. Measurements were made for right and left eyes, with and without cycloplegia, and data were analyzed for large and small pupils. We used the phoropter refraction as our estimate of the true refractive error, so accuracy was defined as the difference between phoropter refraction and that of the COAS and autorefractor. Differences and means were computed using power vectors, and accuracy was summarized in terms of mean vector and mean spherocylindrical power errors. To assess repeatability, we computed the mean vector deviation for each of five measurements from the mean power vector and computed a coefficient of repeatability. Instrument myopia was defined as the difference between cycloplegic and noncycloplegic refractions for the same eyes. Without cycloplegia, both the COAS and autorefractor had mean power vector errors of 0.3 to 0.4 D. Cycloplegia improved autorefractor accuracy by 0.1 D, but COAS accuracy remained the same. For large pupils, COAS accuracy was best when Zernike mode Z4(0) (primary spherical aberration) was included in the computation of sphere power. COAS repeatability was slightly better than autorefraction repeatability. Mean instrument myopia for the COAS was not significantly different from zero. When measuring myopes, COAS accuracy, repeatability, and instrument myopia were similar to those of the autorefractor. Error margins for both were better than the accuracy of subjective refraction. We conclude that in addition to its capability to measure higher-order aberrations, the COAS can be used as a reliable, accurate autorefractor.

Detection of a novel reciprocal t(16;22)(q11.2;q12) in a Ewing sarcoma

Several structural and numerical chromosomal abnormalities have been identified as primary and secondary chromosomal aberrations in Ewing sarcoma (ES). The majority of these are t(11;22) and trisomies, especially of chromosome 8. Specific chromosomal abnormalities often correlate with particular morphologic or phenotypic subtypes of tumor and play an important role in prognosis. The objective of this report is the cytogenetic evaluation of a case of ES using G-banding, fluorescence in situ hybridization, and spectral karyotyping techniques. Multiple chromosomal aberrations were identified including a novel reciprocal t(16;22)(q11.2;q12).

Simulation methods for multipole imaging systems and aberration correctors

Two different methods have been derived and implemented for simulation of multipole imaging systems and aberration correctors. The first method uses an aberration theory for combinations of multipole lenses and deflectors, including primary and secondary aberrations up to the fifth order. A damped least-squares algorithm is used to minimise the dynamically correctable aberrations. This yields the appropriate signals for the dynamic correction elements, e.g. stigmators and dynamic focus lenses. The second method uses a direct ray-tracing approach. The numerically computed multipole lens and deflection fields are fitted with analytic functions through which trajectories are directly traced with a high degree of self-consistency. By computing the paths of many particles simultaneously, the combined effects of aberrations and discrete Coulomb interactions are accurately simulated. Furthermore, the effects of electrical and mechanical asymmetries on the multipole elements can readily be simulated with this approach.

Theory of electron-optical achromats and apochromats

A detailed theoretical formulation of the primary and secondary chromatic aberrations of electron-optical systems with a straight optic axis is outlined. To simplify the mathematical expenditure only systems composed of magnetic round lenses and magnetic and electrostatic quadrupoles are taken into account. By appropriately arranging these elements, it is possible to construct feasible electron-optical analogues of light-optical achromats and apochromats.

High tolerance to spherical aberrations and defects of focus with a birefringent lens.

We report a systematic investigation of the imaging behavior of an optical system consisting of a lens from a uniaxial birefringent crystal sandwiched between two linear polarizers into which primary spherical aberration has been introduced. The proposed system has higher tolerance to primary spherical aberration and has a larger depth of focus than an imaging system found with an isotropic lens. Some specific cases are computed and illustrated graphically.

Multicolor-FICTION: Expanding the Possibilities of Combined Morphologic, Immunophenotypic, and Genetic Single Cell Analyses

Phenotypic and genotypic analyses of cells are increasingly essential for understanding pathogenetic mechanisms as well as for diagnosing and classifying malignancies and other diseases. We report a novel multicolor approach based on the FICTION (fluorescence immunophenotyping and interphase cytogenetics as a tool for the investigation of neoplasms) technique, which enables the simultaneous detection of morphological, immunophenotypic, and genetic characteristics of single cells. As prerequisite, multicolor interphase fluorescence in situ hybridization assays for B-cell non-Hodgkin's lymphoma and anaplastic large-cell lymphoma have been developed. These assays allow the simultaneous detection of the most frequent primary chromosomal aberrations in these neoplasms, such as t(8;14), t(11;14), t(14;18), and t(3;14), and the various rearrangements of the ALK gene, respectively. To establish the multicolor FICTION technique, these assays were combined with the immunophenotypic detection of lineage- or tumor-specific antigens, namely CD20 and ALK, respectively. For evaluation of multicolor FICTION experiments, image acquisition was performed by automatic sequential capturing of multiple focal planes. Thus, three-dimensional information was obtained. The multicolor FICTION assays were applied to well-characterized lymphoma samples, proving the performance, validity, and diagnostic power of the technique. Future multicolor FICTION applications include the detection of preneoplastic lesions, early stage and minimal residual diseases, or micrometastases.

Structural design of broken contact doublets with prespecified aberration targets using genetic algorithm

This paper presents an implementation of a genetic algorithm in the structural design of broken contact doublets according to a prespecified set of Gaussian characteristics and primary aberration targets. The objective of this study is to investigate the effectiveness of the algorithm in finding out global as well as useful local optima and its dependence on some parameters characterizing the genetic operators. Actual glasses are taken as variables. Some illustrative examples are given.

Ablation profiles for wavefront-guided correction of myopia and primary spherical aberration

Purpose: To calculate ablation profiles for wavefront-guided correction of ametropia and primary spherical aberration.Setting: Bascom Palmer Eye Institute, University of Miami, Miami, Florida, USA.Methods: The primary spherical aberrations of the ocular surfaces of an aspheric eye model were calculated before and after simulated ablations for correction of myopia ranging from 0 to 10 diopters. The corneal asphericity to correct primary spherical aberration and the corresponding ablation profiles were also calculated.Results: The corneal asphericity factor that produces zero primary spherical aberration ranges from −0.45 to −0.47. The calculated ablation profiles are parabolic in first approximation, and the ablation depth varies linearly with the amount of correction. To control residual primary spherical aberration with a tolerance of one-quarter wavelength, the precision of the ablation must range from 0.2 to 0.3 μm.Conclusions: Ocular aberrometry and corneal topography can be used to calculate ablations for the correction of ametropia and primary spherical aberration. Precise control of postoperative spherical aberration appears to be feasible in theory.

The factor of encircled energy from the optical transfer function

This paper proposes a generalized technique for computing the factor of encircled energy (FEE) in a diffraction image from the optical transfer function (OTF) of the imaging system. This technique is applicable to diffraction-limited optical systems as well as to systems suffering from any aberrations, provided the transfer function of the same is known. It is also applicable to any kind of rotationally symmetric or asymmetric apertures. The accuracy of the results depends on the precision with which the OTF of the system can be determined. The FEE values are obtained using this technique for an aberration-free spherical lens as well as for the same having primary spherical aberration. The results are computed for the Gaussian image plane and other observation planes and are compared with the previously reported results. A numerical technique for computing the FEE in a diffraction pattern formed by a conventional lens suffering from off-axis aberrations and that formed by rotationally asymmetric apertures is also depicted.

Secondary chromosomal abnormalities in acute lymphoblastic leukemia

AbstractSecondary chromosomal abnormalities (both numerical and structural) were studied in 55 Acute Lymphoblastic Leukaemia (ALL) patients of Orissa (India) of which only 44 patients could provide good chromosome spreads. In addition to the primary aberrations, these patients exhibited various kinds of secondary aberrations like hyperdiploids, pseudodiploids, aneuploids, stickiness, pulverisation, chromatin extraction, chromatid gap, chromatin constriction, isochromatid breaks, endomitoses, ring chromosomes etc. These aberrations appeared either singly or in various combinations. A majority (40 out of 44) of studied patients possessed secondary aberrations. The frequencies of secondary aberrations were found to increase with the progression of the disease and patients with highest number of such aberrations had the worst chance of survival. The probable causes and the prognostic implications of these aberrations are discussed.

Identification of primary aberrations on a lateral shearing interferogram of optical components using neural network

A method is proposed for the identification of primary aberrations with a single image of a lateral shearing interferogram of optical components, obtained from a monochromatic laser source, using a neural network. The neural network is used to illustrate the features of the sampled interferograms and identify the primary aberrations of the other interferograms by means of its excellence in interpolation and extrapolation. Analysis of the pattern is performed to find the proper features to teach the neural network in less time. Simulations are performed to verify the suggested method.

Experiments with a genetic algorithm for structural design of cemented doublets with prespecified aberration targets

The authors use a genetic algorithm in the structural design of cemented doublets in accordance with a prespecified set of Gaussian characteristics and primary aberration targets. Actual glasses are taken as variables. Suitable modifications in the algorithm are sought with which to explore the solution space in search of the global as well as useful local optima. Some illustrative examples of structural design are given.