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Stabilization of the mutual position of the focal plane and the observed object in the holographic microscope
Ha Trinh, Hung Son ; Brada, Michal (oponent) ; Dostál, Zbyněk (vedoucí práce)
The coherence-controlled holographic microscope (CCHM) makes the study of native biological samples in real-time possible. However, during long-term observation sessions, a defocusation of observed objects occurs. This undesirable phenomenon is probably caused by changes in the mutual position of the focal plane and the observed object. Thermal changes within the CCHM are thought to be the reason behind the displacement. A need for a hardware-based autofocus system, which would complement the currently implemented solution and which could compensate for the insufficiencies of the software autofocus, has therefore emerged. First, the optical setup of the CCHM is briefly described. Afterwards, the principle of the current autofocusation solution is explained. Subsequently, several displacement detection and monitoring methods, which can be utilized in a feedback loop to maintain a defined mutual position of objects, are introduced. After discussing the advantages and disadvantages of each method, one is selected for the practical part of the thesis. Based on the chosen method, a device that stabilizes the mutual position of the focal plane and the observed object is designed, constructed and experimentally tested.
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Stabilization of the mutual position of the focal plane and the observed object in the holographic microscope
Ha Trinh, Hung Son ; Brada, Michal (oponent) ; Dostál, Zbyněk (vedoucí práce)
The coherence-controlled holographic microscope (CCHM) makes the study of native biological samples in real-time possible. However, during long-term observation sessions, a defocusation of observed objects occurs. This undesirable phenomenon is probably caused by changes in the mutual position of the focal plane and the observed object. Thermal changes within the CCHM are thought to be the reason behind the displacement. A need for a hardware-based autofocus system, which would complement the currently implemented solution and which could compensate for the insufficiencies of the software autofocus, has therefore emerged. First, the optical setup of the CCHM is briefly described. Afterwards, the principle of the current autofocusation solution is explained. Subsequently, several displacement detection and monitoring methods, which can be utilized in a feedback loop to maintain a defined mutual position of objects, are introduced. After discussing the advantages and disadvantages of each method, one is selected for the practical part of the thesis. Based on the chosen method, a device that stabilizes the mutual position of the focal plane and the observed object is designed, constructed and experimentally tested.
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Fiber-Coupled Fabry-Pérot Interferometric Sensor: Analysis And Modelling
Skalský, Michal
This paper presents a theoretical analysis of the Fabry-Pérot interferometric sensor utilizingan extrinsic fiber-optic cavity. Its behavior is modelled and simulated for various conditions,showing the key properties of the different sensor’s setups. The simple single-mode sensing tip andthe GRIN collimator are compared. Further, new kind of sensing head is proposed exhibiting aninverse reflectivity and enabling a theoretical resolution less than 1 pm.
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