Academic literature on the topic 'Koherencí řízená holografická mikroskopie'

This thesis deals with imaging through diffuse media in coherence-controlled holographic microscope (CCHM) developed in IPE FME BUT. The mutual coherence function as well as the signal dependence on the lateral mutual shift between both arms of the CCHM are calculated. Both functions are related to each other. The latter dependence is measured experimentally. A principle of imaging with CCHM through diffuse media with both ballistic and diffuse light is explained by a simple geometrical model. This model is then verified experimentally by imaging a sample through diffuse medium. The point spread function (PSF) of CCHM for imaging through diffuse media is then calculated. Results of PSF calculation are proved experimentally.

The Coherence Controlled Holographic Microscope (CCHM) was developed at BUT Brno for a quantitative phase imaging of living cells. Nowadays it ocurres that its imaging properties are enhanced by the use of additional modules. In the present the microscope is equipped with the epifluorescence module, which allows observation of fluorescently marked living cells. This thesis is going to follow up on the development of this module and is going to extend its options by confocal imaging. The disadvantage of current multi-channel confocal microscopes is a mechanical rotation of the Nipkow discs, which causes undesired mechanical vibrations. That is why in this thesis it is replaced by Digital Micromirror Device. With its use was developed optical system of the whole confocal model, whose correct funcion was simulated in optical CAD. The experimentally verified prototype serves to test the imaging properties. On this basis is designed an application idea of the fluorescence confocal module, which will be possible to connect to the CCHM microscope.

The goal of this diploma thesis was using of a coherence-controlled holographic microscope in cell’s life research. A brief history of interference microscopy and it’s applications in biology is described. Also other microscopy techniques routinely used for transparent objects imaging are mentioned and the biology of cell’s life cycle briefly explained. Characteristics describing the shape of a cell were proposed and tested with respect to identification of particular phases of its life cycle. The method of dynamic phase differences was modified in order to distinguish the internal motion of cell’s mass from the movement of the whole cell. Selected characteristics were used to evaluate observations carried out with the holographic microscope and the possibilities of their further applications were depicted. In conclusion, obtained findings were summarized and modifications of microscope construction as well as data-processing software were suggested.

This diploma thesis deals with phase and amplitude objects observation through scattering media by means of a coherence-controlled holographic microscope (CCHM). A brief history of development and construction of the microscope, its advantages compared to the classical light microscopy and hologram processing are described. Quantitative phase imaging through scattering media by means of ballistic as well as diffuse light is verificated in the experimental part. A comparison of an image obtained through a scattering layer by means of CCHM and a classical microscopy in the light field is demonstrated.

ransmitted-light coherence-controlled holographic microscope (CCHM) based on an off-axis achromatic and space-invariant interferometer with a diffractive beamsplitter has been designed, constructed and tested. It is capable to image objects illuminated by light sources of arbitrary degree of temporal and spatial coherence. Off-axis image-plane hologram is recorded and the image complex amplitude (intensity and phase) is reconstructed numerically using fast Fourier transform algorithms. Phase image represents the optical path difference between the object and the reference arms caused by presence of an object. Therefore, it is a quantitative phase contrast image. Intensity image is confocal-like. Optical sectioning effect induced by an extended, spatial incoherent light source is equivalent to a conventional confocal image. CCHM is therefore capable to image objects under a diffusive layer or immersed in a turbid media. Spatial and temporal incoherence of illumination makes the optical sectioning effect stronger compared to a confocal imaging process. Object wave reconstruction from the only one recorded interference pattern ensures high resistance to vibrations and medium or ambience fluctuations. The frame rate is not limited by any component of the optical setup. Only the detector and computer speeds limit the frame rate. CCHM therefore allows observation of rapidly varying phenomena. CCHM makes the ex-post numerical refocusing possible within the coherence volume. Coherence degree of the light source in CCHM can be adapted to the object and to the required image properties. More coherent illumination provides wider range of numerical refocusing. On the other hand, a lower degree of coherence makes the optical sectioning stronger, i.e. the optical sections are thiner, it reduces coherence-noise and it makes it possible to separate the ballistic light. In addition to the ballistic light separation, CCHM enables us to separate the diffused light. Multi-colour-light

This doctoral thesis deals with design of a new generation of coherence-controlled holographic microscope (CCHM). The microscope is based on off-axis holographic configuration using diffraction grating and allows the use of temporally and spatially incoherent illumination. In the theoretical section a new optical configuration of the microscope is proposed and conditions for different parameters of the microscope and its optical components are derived. The influence of different sources of noise on phase detection sensitivity is studied. In the next section design of experimental setup is described and automatable adjustment procedure is proposed. Last section describes experimental verification of the most important optical parameters of the experimental setup. When compared to previous generation of CCHM, the newly proposed configuration uses infinity-corrected objectives and common microscope condensers, allows more space for the specimens, eliminates the limitation of spectral transmittance and significantly simplifies the adjustment procedure so that automation of this procedure is possible.

In the master's thesis, there has been described and explained the principle of operation of the second generation coherence controlled holographic microscope (CCHM2) designed at the Brno University of Technology. There has also been listed theoretical description of the operation of the optical trap, together with the calculation of the forces acting on it, ways of measuring the stiffness of the optical trap and the principle of~creating a time-shared optical traps. The optical tweezers forming a separate module connectable to CCHM2 was designed. Simulation and optimization of parameters of the optical system, mechanical design, manufacturing documentation, current source to power the laser diode which allows to control the diode output power by the controller card connected to the PC was designed. The galvano-optics mirror angle is controlled by the PC card too. The optical tweezer has been designed, manufactured and tested in conjunction with the CCHM2.

The Digital Micromirror Device (DMD) technology has been developed especially for Digital Light Processing projectors, which allow the image projection. After this succesful implementation, and thanks to the commercial availibility and low initial cost of the DMD chip, a wide range of other applications became possible. Besides, it may be used in microscopy as a spatial light modulator. For example in Coherence-Controlled Holographic Microscope (CCHM) that finds its use especially for imaging and measurement of live-cell dynamic processes. The DMD chip placed in the illumination part of CCHM allows for broadening the application possibilities. Namely it could be different illumination mode experiments or tomographic applications. The master's thesis deals with the optical design of CCHM with digital optics, i. e. DMD chip. The selection of optical elements for CCHM, the experimental verification of the imaging setup and the process of designing the illumination part are described in detail. In the end, the analysis of different designs for illumination setup with the digital optics in object arm is carried out and the results are compared.

Coherence-Controlled Holographic Microscope (CCHM) and a Fluorescence Holographic Microscope (FHM) were developed particularly for quantitative phase imaging and measurement of live cell dynamics, which used to be a subject of digital holographic microscopy (DHM). CCHM and FHM in low-coherence mode extend capabilities of DHM in the study of living cells. However, this advantage following from the use of low coherence is accompanied by increased sensitivity of the system to its correct alignment. Therefore, the introduction of an automatic self-correcting system is inevitable. Accordingly, in the thesis, the theory of a suitable control system is derived and the design of an automated alignment system for both microscopes is proposed and experimentally proved. The holographic signal was identified as a significant variable for guiding the alignment procedures. On this basis the original basic realignment algorithms were proposed, which encompasses the processes for initial and advanced alignment as well as for long-term maintenance of the microscope aligned state. Automated procedures were implemented in both microscopes unique set of robotic mechanisms designed and built within the frame of the thesis work. All of the procedures described in the thesis were in real experimentally proved at real microscopes in the experimental biophotonics laboratory. In addition, the control software, which contains the needed automated procedures, was developed for FHM.

This thesis deals with the topic of 3D image processing for digital holographic microscopy - numerical refocusing. This method allows to perform mathematically accurate defocus correction on image of a sample captured away from the sample plane and it was applicable only for images that were made made using coherent illumination source. It has been generalized to a form in which it is also applicable to devices that use incoherent (non-monochromatic or extended) illumination sources. Another presented achievement concerns hologram processing. The advanced hologram processing method enables obtaining more data mainly concerning precision of quantities from one hologram — normally, one would have to capture multiple holograms to get those. Both methods have been verified experimentally.