| 1. |
- Burvall, Anna, et al.
(författare)
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Communication modes applied to axicons
- 2004
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Ingår i: Optics Express. - 1094-4087. ; 12:3, s. 377-383
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Tidskriftsartikel (refereegranskat)abstract
- The communication modes, which constitute a convenient method for the propagation and information analysis of optical fields, are formulated in the generalized axicon geometry. The transmitting region is the axicon’s annular aperture, and the observation domain is the optical axis containing the focal line segment. We show that in rotational symmetry one may employ the prolate spheroidal wave functions to represent the communication modes. Further, in usual circumstances the modes can be approximated by quadratic waves in the aperture domain and by sinc functions in the image domain. Both the exact communication modes and the approximate technique are confirmed numerically, with linear axicons as examples.
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| 2. |
- Einbeigi, Zakaria, 1962, et al.
(författare)
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Occurrence of both breast and ovarian cancer in a woman is a marker for the BRCA gene mutations: a population-based study from western Sweden.
- 2007
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Ingår i: Familial cancer. - : Springer Science and Business Media LLC. - 1389-9600 .- 1573-7292. ; 6:1, s. 35-41
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Tidskriftsartikel (refereegranskat)abstract
- AIM: This study aimed to analyze whether the occurrence of both breast and ovarian cancer in a woman serves as a marker for BRCA gene mutations. MATERIAL AND METHODS: This population-based study included 256 women in western Sweden who developed both invasive breast and ovarian tumors between 1958 and 1999. Archival paraffin tissue blocks of their tumors were retrieved for DNA-extraction to analyze the founder mutation, BRCA1 c.3171_3175dup (c.3171ins5), which is most common in this geographic area and four other common Scandinavian BRCA1 gene mutations and one BRCA2 mutation. Together, account these mutations for approximately 75% of the BRCA1/2 gene mutations in the clinical unit. RESULTS: Ninteen percent (95% confidence interval (CI) 14-24%) of the women carried one of the analyzed BRCA1 gene mutations but none of the women were positive for the analyzed BRCA2 mutation. One-third of the women with both tumors before age 60 were mutation carriers. BRCA1 c.3171_3175dup (c.3171ins5) constituted 84% of all identified mutations. Although the majority of breast cancers were invasive ductal and atypical medullary types, a variety of other breast malignancies were seen among mutation carriers. Serous ovarian carcinomas predominated among ovarian tumors. A variety of other ovarian tumors, including three granulosa-theca cell tumors, were also observed among mutation carriers. CONCLUSIONS: The occurrence of both breast and ovarian cancer in a woman is associated with a high likelihood of a constitutional BRCA1 mutation. These women and their families might therefore be considered for mutation screening after appropriate genetic counselling.
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| 3. |
- Martinsson, Per, 1971-, et al.
(författare)
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Communication modes with partially coherent fields
- 2007
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Ingår i: Journal of the Optical Society of America A. - 0740-3232. ; 24:10, s. 3336-3342
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Tidskriftsartikel (refereegranskat)abstract
- We develop a theory for the description of partially coherent wave fields in linear optical systems in terms of the so-called communication modes. The communication modes are the singular functions and singular values of the appropriate propagation kernels. In particular, we show that optical fields of any state of coherence may be readily propagated through deterministic systems using the modal representation based on the system properties. The relation of the communication modes to the conventional coherent-mode representation is discussed, and expressions for the effective degree of coherence in the optical system are derived. The results are illustrated by numerical examples in optical near-field geometry.
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| 4. |
- Martinsson, Per, 1971-, et al.
(författare)
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Communication modes in scalar diffraction
- 2008
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Ingår i: Optik (Stuttgart). - : Elsevier BV. - 0030-4026 .- 1618-1336. ; 119:3, s. 103-111
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Tidskriftsartikel (refereegranskat)abstract
- The communication modes are a useful concept in studies of optical resolution, wave propagation, and image synthesis. We present an overview of earlier results on the communication modes in scalar diffraction theory. Besides the general theory, the modes are reviewed for the far-field and Fresnel regimes, and new eigenequations are derived for wide-angle diffraction. We prove a conjugate relationship between the transmitting and receiving modes in a general symmetric system. We also suggest an approximate method for far-field and Fresnel domain propagation, in which propagation amounts to a rotation of each mode in the complex plane. The main focus is on the near-field communication modes, where we present numerical examples of the modes and coupling strengths for a near-field geometry with a sub-wavelength size receiving domain. These results provide insights, for example, into the understanding of near-field scanning probe techniques.
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| 5. |
- Martinsson, Per, 1971-, et al.
(författare)
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Scanning optical near-field resolution analyzed in terms of communication modes
- 2006
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Ingår i: Optics Express. - 1094-4087. ; 14:23, s. 11392-11401
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Tidskriftsartikel (refereegranskat)abstract
- We present an analysis of scanning near-field optical microscopy in terms of the so-called communication modes using scalar wave theory. We show that the number of connected modes increases when the scanning distance is decreased, but the number of modes decreases when the size of the scanning aperture is decreased. In the limit of small detector aperture the best-connected mode reduces effectively to the Green function, evaluated at the center of the scanning aperture. We also suggest that the resolution of a scanning optical near-field imaging system is essentially given by the width of the lowest-order communication mode.
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| 6. |
- Martinsson, Per, 1971-
(författare)
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Structural Information Content of the Optical Field
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The communication modes are a mathematical technique for the description of structural information in optical fields. These modes are orthogonal, optimally connected functions characteristic of the optical system. Mathematically they are obtained by the singular value decomposition (SVD) of the operator that represents the field propagation. In this dissertation, the foundations of the technique are described, and the theory is extended and applied to a variety of specific systems. In the Fresnel regime, the communication modes are closely related to the prolate spheroidal wavefunctions (PSWF). Within this approximation, the numerical propagation of the field in a one-dimensional optical system in terms of the PSWFs is demonstrated and the problem of assessing the best achievable realization of a given target field is addressed. Simplified equations for field propagation are presented. Approximate modes in large-aperture systems are derived and shown to agree with Gabor's theory on optics and information. The longitudinal resolution of an axicon is analyzed in terms of the communication modes. It is shown that in a generalized axicon geometry the communication modes are expressible in terms of the PSWFs, and that in usual circumstances a version of the large aperture approximation applies, resulting in quadratic waves in the aperture domain and sinc functions in the image domain Eigenequations for the communication modes in scalar near-field diffraction are derived and applied to a simplified scanning near-field optical microscope (SNOM) geometry. It is suggested that the resolution of a SNOM system is essentially given by the width of the lowest-order communication modes. The best-connected mode is shown to effectively reduce to the Green function. Within the context of random fluctuations the communication modes are defined for the cross-spectral density of partially coherent fields. These modes are compared to the well-known coherent modes. Expressions for the effective degree of coherence are derived, and it is demonstrated that optical fields of any state of coherence may readily be propagated through deterministic systems by means of the communication modes. Results are illustrated numerically in an optical near-field geometry. The communication modes theory is further extended to vector diffraction on the basis of Maxwell's equations. The polarization properties of the electromagnetic communication modes as represented by the Stokes parameters are analyzed numerically for an example of a near-field geometry.The work presented in this dissertation shows that the communication modes are an advanced, versatile tool that can be applied to deterministic and random, scalar and electromagnetic optical systems in far-field and near-field arrangements. The method is likely to find further uses in applications such as polarization microscopy.
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| 7. |
- Thaning, Anna, et al.
(författare)
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Limits of diffractive optics by communication modes
- 2003
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Ingår i: Journal of Optics. A, Pure and applied optics. - : IOP Publishing. - 1464-4258 .- 1741-3567. ; 5, s. 153-158
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Tidskriftsartikel (refereegranskat)abstract
- We apply the concept of communication modes, previously employed in information theory, to diffractive optics. The communication modes are used to study the resolution of one-dimensional optical systems in the Fresnel regime. Using the modes, which in this geometry are prolate spheroidal wavefunctions, the best achievable approximation to a given target field can be assessed. In this paper, the field propagation in terms of the communication modes is demonstrated numerically, and the results on resolution are confirmed by Fourier analysis.
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