Journal of the Optical Society of America, Aug 1, 2000
The radiometric theory of spatial coherence is presented with special attention to the validity o... more The radiometric theory of spatial coherence is presented with special attention to the validity of the approximations on which it is based. A new definition of the transverse coherence area is introduced and shown to be in general agreement with earlier definitions. In free-space propagation the product of the transverse coherence area and the intensity is shown to be constant along rectilinear rays, and, for radiation from uniform Lambert sources, a well-known paraxial formula for the transverse coherence area is extended to the extraparaxial domain. A decrease of the spatial coherence in free-space propagation takes place in regions with an increase of the intensity. For imaging systems this occurs in a finite part of image space whenever a real image of a diffusely radiating, extended object is formed at a finite distance.
We compare focusing properties of conventional lenses and diffractive lenses (DLs). To that end, ... more We compare focusing properties of conventional lenses and diffractive lenses (DLs). To that end, we use a converging electric-dipole wave as a modelof an optimal converging wavefront that emerges from a conventional lens system. Our numerical results show that DLs have better focusing properties than conventional lenses for f-numbers less than 1. Although both types of lenses give nearly indistinguishable
We compare theoretical and experimental results for focusing of two-dimensional scalar waves in t... more We compare theoretical and experimental results for focusing of two-dimensional scalar waves in the presence of cylindrical aberration and coma and show that good agreement can be obtained by a proper choice of the aberration coefficients. Therefore, such comparisons can be used to obtained an accurate estimate of both first-order and higher-order aberrations. We restrict our attention to systems of sufficiently low angular aperture that a scalar theory is adequate.
With applications in medical diagnosis in mind we apply the theory of diffraction tomography to d... more With applications in medical diagnosis in mind we apply the theory of diffraction tomography to diffuse photon density waves in a random medium. We consider the two-and-a-half-dimensional (2.5D) problem in which a two-dimensional (2D) object is illuminated by diffuse photon density waves from a point source. Both the forward problem and the inverse problem are discussed, and a reconstruction algorithm
Journal of the Optical Society of America, Aug 1, 2000
The radiometric theory of spatial coherence is presented with special attention to the validity o... more The radiometric theory of spatial coherence is presented with special attention to the validity of the approximations on which it is based. A new definition of the transverse coherence area is introduced and shown to be in general agreement with earlier definitions. In free-space propagation the product of the transverse coherence area and the intensity is shown to be constant along rectilinear rays, and, for radiation from uniform Lambert sources, a well-known paraxial formula for the transverse coherence area is extended to the extraparaxial domain. A decrease of the spatial coherence in free-space propagation takes place in regions with an increase of the intensity. For imaging systems this occurs in a finite part of image space whenever a real image of a diffusely radiating, extended object is formed at a finite distance.
We compare focusing properties of conventional lenses and diffractive lenses (DLs). To that end, ... more We compare focusing properties of conventional lenses and diffractive lenses (DLs). To that end, we use a converging electric-dipole wave as a modelof an optimal converging wavefront that emerges from a conventional lens system. Our numerical results show that DLs have better focusing properties than conventional lenses for f-numbers less than 1. Although both types of lenses give nearly indistinguishable
We compare theoretical and experimental results for focusing of two-dimensional scalar waves in t... more We compare theoretical and experimental results for focusing of two-dimensional scalar waves in the presence of cylindrical aberration and coma and show that good agreement can be obtained by a proper choice of the aberration coefficients. Therefore, such comparisons can be used to obtained an accurate estimate of both first-order and higher-order aberrations. We restrict our attention to systems of sufficiently low angular aperture that a scalar theory is adequate.
With applications in medical diagnosis in mind we apply the theory of diffraction tomography to d... more With applications in medical diagnosis in mind we apply the theory of diffraction tomography to diffuse photon density waves in a random medium. We consider the two-and-a-half-dimensional (2.5D) problem in which a two-dimensional (2D) object is illuminated by diffuse photon density waves from a point source. Both the forward problem and the inverse problem are discussed, and a reconstruction algorithm
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Papers by Jakob Stamnes