|
|
New Generation of a Coherence-Controlled Holographic Microscope
Slabý, Tomáš ; Novák,, Jiří (referee) ; Jákl, Petr (referee) ; Chmelík, Radim (advisor)
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.
|
|
|
Possibilities of three-dimensional imaging in transmitted-light holographic microscope
Sládková, Lucia ; Jákl, Petr (referee) ; Kolman, Pavel (advisor)
Digital holographic microscopy (DHM) is noninvasive method for obtaining images even from samples with low contrast. Nowadays DHM design makes it possible to illuminate sample by broad light source, halogene lamp. Broad light source is displayed in the front focal plane of condensor in such way, that Köhler illumination is achieved. Each point of the source corresponds to a plane wave in image field of objective, which illuminates the whole field of view, but from different direction. Position of the point determines the direction of illumination. In this reason, the microscope enables so reconstruct not only intensity, but also phase of object wave. New designed and constructed interchangeable pinhole aperture modify broad light illumination by rotation around the optical axis. Aperture is placed eccentrically considering the optical axis of microscope. Incidence of light beam on a sample would be under defined angle. After the reconstruction of taken phase images from individual angles of illumination should be possible to obtain three-dimensional structure of the sample.
|
|
|
Optical tweezers for coherence-controlled holographic microscope
Straka, Branislav ; Jákl, Petr (referee) ; Dostál, Zbyněk (advisor)
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.
|
|
|
Computer Generated Holograms
Tvarog, Drahoslav ; Jákl, Petr (referee) ; Kotačka, Libor (advisor)
The presented Diploma thesis deals with the computer-generated diffractive structures or rather called computer generated holograms (CGH). We follow basic principles of classical holography and in the context of which we define a synthetic holography. We then show various types of digital holograms and methods of measurement of their quality. We deal with several iterative algorithms useful for computation of the Fourier transform as well as with methods of phase quantization. In the second part of the work, we describe briefly our computer code for iterative Fourier transform computation. With respect to the mentioned techniques, we further present the usability of the method for design of computer generated holograms in reflection regime. After a short introduction to the electron beam lithography and its exploitation for the origination of computer generated diffractive optical elements. We analyze reconstructions of produced holograms and evaluate its quality.
|
|
|
Controlling and Evaluation of Laser Micromanipulation Experiments
Kaňka, Jan ; Jákl, Petr (referee) ; Provazník, Ivo (advisor)
This work is focused on the development of a user friendly software interface using the LabViewTM environment that simplifies running of various experiments using laser micromanipulations and laser microspectroscopy of living microorganisms. Both techniques have been developing very fast for the last decade and belong to the growing group of contact-less and nondestructive techniques for manipulation and diagnostics of individual living microorganisms, cells, or viruses. Within this project we mastered the driving of peripheries, calibration of CCD scene, real-time image processing of the CCD scene, automatic selection of the cell for further laser processing, acquisition and processing of the Raman spectrum from living microorganisms. The final goal of our activity is fully automatic laser-based sorter of living cells depending on their chemical compositions. This work has been elaborated at the Institute of Scientific Instruments of the ASCR, v.v.i. under the supervision of prof. Pavel Zemanek.
|
|
|
SMV-2015-36: „Light Sheet“ microscope combining three wavelengths
Ježek, Jan ; Kaňka, Jan ; Jákl, Petr ; Šerý, Mojmír
The equipment is used for 3D scanning of fluorescence in biological samples. Three lasers with wavelengths suitable for biological samples are used for the excitation of fluorescent dyes. The image is scanned by a highly sensitive CCD camera. Switching between different excitation lasers is controlled by a computer. The observed sample is held in a holder mounted on a four-axis table (3 axes for moving a sample, one axis of rotation around the axis of the sample). The equipment is used to capture images of the sample in different positions of the positioning table.
|
|
| |
|
|
Noise to signal transition: work obtained from noise studied by the optical tweezers
Šiler, Martin ; Filip, R. ; Jákl, Petr ; Brzobohatý, Oto ; Zemánek, Pavel
The noise-to-signal transitions are very interesting processes in physics as they might transform environmental noise to useful mechanical effects. In this contribution we introduce the problem of stochastic noise-to-signal transition of overdamped Brownian motion of a particle in the cubic potential. The particle reaches thermal equilibrium with its environment in the quadratic potential which is suddenly swapped to the cubic potential. We predict simultaneous increase of both the displacement and signal-to-noise ratio in the cubic potential for the position linearly powered by temperature of the particle environment. Further, we propose a feasible experimental setup for proof-of-the-principle experiment that uses methods of optical trapping in shaped laser beams providing cubic and quadratic potentials.
|
|
|
SMV-2014-09: Nanolithography system based on two-photon photopolymerization
Jákl, Petr
The research contract deals with development of experimental setup for dynamic shaping of laser beams using computer generated holographic phase masks, focusing of independently addressed laser beams and spatial modulation of optical intensity. By synchronization of fast laser beam shutter and position of 3D nanostage, it is possible to change the state of photo-polymeric material in well-defined micro-volumes, so called voxels. This way, surface structures or microscopic objects are created with details in the range of 100s of nanometers.
|
|
|
SMV-2013-19: Nanolithography system based on two-photon photopolymerization
Jákl, Petr ; Šerý, Mojmír ; Zemánek, Pavel
The reasearch contract deals with development of experimental setup for dynamic shaping of laser beams. Using computer generated holographic phase masks, it is possible to create independent foci of laser beams in the sample space, change their intensity profiles and power of each diffracted beam. By employing fast acousto-optic modulator, the complex procedure allows control of sample irradiation within microsecond resolution. It is possible to precisely select sample region for laser impact using computer-controlled nano-positioning stage.
|
guest ::
