Book of abstracts, Digital Humanities Conference Krakow, 2016
This paper presents initial findings of the research project Making Sense of Illustrated Handwrit... more This paper presents initial findings of the research project Making Sense of Illustrated Handwritten Archives and demonstrates the recognition capabilities of the MONK artificial intelligence system developed at the institute of Artificial Intelligence and Cognitive Engineering (ALICE) at Groningen University. In a period of four years (2016-2019), our research project aims to produce an innovative and user-friendly tool, that combines both image and textual recognition, and allows an integrated study of fragmented historical heritage collections. Next to a short demonstration of MONK, we use this paper to outline how handwriting and image recognition helps to enrich the value of illustrated handwritten collections by adding information now inaccessible and disconnected. By doing so it advances the state of the art in automated extraction, classification, and networking of knowledge from heterogeneous manuscript collections and archives.
We present a simple geometrical-optics model for the excess-noise factor of a hard-edged unstable... more We present a simple geometrical-optics model for the excess-noise factor of a hard-edged unstable-resonator laser. When we ad hoc incorporate the numerically calculated diffraction losses in this model we find similar behavior to results from the more complex mode-nonorthogonality theory. Under certain conditions the predictions of our model are in reasonable agreement with mode-nonorthogonality theory; phenomena such as the resonant behavior of the excess-noise factor with Fresnel number and the dependence of the excess-noise factor on the transverse resonator symmetry are recovered. However, in the general case there is no quantitative agreement between the two approaches. We confirm this with an experiment on an unstable-cavity He-Xe laser. Severe deviations occur for values of the round-trip magnification close to unity or much larger than unity and for higher-order modes. This illustrates the profound consequences of mode-nonorthogonality theory, which are apparently much more subtle than can be described by a model directly based on losses.
... 4314 0031-9007 96 77(21) 4314(4)$10.00 Note that the quantum-noise properties of a hard-edged... more ... 4314 0031-9007 96 77(21) 4314(4)$10.00 Note that the quantum-noise properties of a hard-edged unstable-resonator laser are described by two parameters only: the round-trip linear magnification M and the M 2 2 1 a2 2MlB equivalent Fresnel number Neq where l is the ...
We demonstrate that the quantum-limited linewidth of an unstable-cavity laser depends on the tran... more We demonstrate that the quantum-limited linewidth of an unstable-cavity laser depends on the transverse symmetry of the resonator. This is due to the occurrence of excess noise associated with the nonorthogonality of the eigenmodes of an unstable-cavity laser. We show that square symmetry leads to considerably larger excess noise than circular symmetry, confirming recent predictions. Further we present measurements of
We present measurements of the higher order transverse modes of an unstable-cavity HeXe gas laser... more We present measurements of the higher order transverse modes of an unstable-cavity HeXe gas laser. We have studied the one-dimensional strip-resonator modes and the two-dimensional square- and circular-resonator modes. The experimental intensity profiles showed generally good agreement with theoretical profiles based upon virtual-source diffraction theory. We also measured the quantum-limited linewidths and excess-noise factors of several of these modes
Book of abstracts, Digital Humanities Conference Krakow, 2016
This paper presents initial findings of the research project Making Sense of Illustrated Handwrit... more This paper presents initial findings of the research project Making Sense of Illustrated Handwritten Archives and demonstrates the recognition capabilities of the MONK artificial intelligence system developed at the institute of Artificial Intelligence and Cognitive Engineering (ALICE) at Groningen University. In a period of four years (2016-2019), our research project aims to produce an innovative and user-friendly tool, that combines both image and textual recognition, and allows an integrated study of fragmented historical heritage collections. Next to a short demonstration of MONK, we use this paper to outline how handwriting and image recognition helps to enrich the value of illustrated handwritten collections by adding information now inaccessible and disconnected. By doing so it advances the state of the art in automated extraction, classification, and networking of knowledge from heterogeneous manuscript collections and archives.
We present a simple geometrical-optics model for the excess-noise factor of a hard-edged unstable... more We present a simple geometrical-optics model for the excess-noise factor of a hard-edged unstable-resonator laser. When we ad hoc incorporate the numerically calculated diffraction losses in this model we find similar behavior to results from the more complex mode-nonorthogonality theory. Under certain conditions the predictions of our model are in reasonable agreement with mode-nonorthogonality theory; phenomena such as the resonant behavior of the excess-noise factor with Fresnel number and the dependence of the excess-noise factor on the transverse resonator symmetry are recovered. However, in the general case there is no quantitative agreement between the two approaches. We confirm this with an experiment on an unstable-cavity He-Xe laser. Severe deviations occur for values of the round-trip magnification close to unity or much larger than unity and for higher-order modes. This illustrates the profound consequences of mode-nonorthogonality theory, which are apparently much more subtle than can be described by a model directly based on losses.
... 4314 0031-9007 96 77(21) 4314(4)$10.00 Note that the quantum-noise properties of a hard-edged... more ... 4314 0031-9007 96 77(21) 4314(4)$10.00 Note that the quantum-noise properties of a hard-edged unstable-resonator laser are described by two parameters only: the round-trip linear magnification M and the M 2 2 1 a2 2MlB equivalent Fresnel number Neq where l is the ...
We demonstrate that the quantum-limited linewidth of an unstable-cavity laser depends on the tran... more We demonstrate that the quantum-limited linewidth of an unstable-cavity laser depends on the transverse symmetry of the resonator. This is due to the occurrence of excess noise associated with the nonorthogonality of the eigenmodes of an unstable-cavity laser. We show that square symmetry leads to considerably larger excess noise than circular symmetry, confirming recent predictions. Further we present measurements of
We present measurements of the higher order transverse modes of an unstable-cavity HeXe gas laser... more We present measurements of the higher order transverse modes of an unstable-cavity HeXe gas laser. We have studied the one-dimensional strip-resonator modes and the two-dimensional square- and circular-resonator modes. The experimental intensity profiles showed generally good agreement with theoretical profiles based upon virtual-source diffraction theory. We also measured the quantum-limited linewidths and excess-noise factors of several of these modes
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