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Pokročilé techniky optických mikromanipulací
Zemánek, Pavel ; Čižmár, Tomáš ; Šiler, Martin ; Jákl, Petr ; Šerý, Mojmír ; Karásek, Vítězslav ; Brzobohatý, Oto
Nowadays the classical tool of optical micro-manipulations - optical tweezers - found numerous applications in physics, biology and chemistry. However new techniques were developed that used more sophisticated laser beam tailoring and enable to modify positions and number of manipulated objects dynamically, to sort optically objects according to their properties, to deliver them over millimetre long distances or even to let them self-organize after light illumination. We present several results dealing with the above mentioned advanced techniques developed in our laboratory.
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Study of mechanical properties and dynamics of biomembranes and single molecules with the use of laser beam - an overview
Jonáš, Alexandr ; Zemánek, Pavel
A micron-sized dielectric particle confined in a laser trap can be employed as a probe for the measurement of forces in the range from piconewtons to hundreds of piconewtons. Thus, if a biological system of interest (e.g. DNA molecule, single myosin or kinesin molecule, cell membrane) is attached to such a probe, its mechanical and dynamical properties (elasticity, viscosty, forces associated with movement) can be studied during its interaction with the environment with unprecedented resolution. This article introduces the basic principles of the laser trapping and force measurement and illustrates on several examples the great potential of the light-based force transducer for exploiting non-invasively the dynamics of basic biological systems.
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Study of the Behaviour of Microparticle in the Standing Wave Trap
Ježek, Jan ; Jonáš, Alexandr ; Zemánek, Pavel ; Liška, M.
The basic behavior of microparticles placed in the Gaussian standing wave is studied theoretically and experimentally in this article. It is shown that the optical force depends periodically on the particle size and, as the consequence, the equilibrium object position is alternating between the standing wave antinodes and nodes. For certain particle sizes, the particle confinement is disabled. Experimental confirmation of the theoretical results is briefly discussed.
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Measurement of the Optical Trap Stiffness
Jákl, Petr ; Jonáš, Alexandr ; Zemánek, Pavel ; Liška, M.
An optical trap for dielectric microparticles is usually approximated by a parabolic potential well, whose profile is characterized by a single constant - trap stiffness. This stiffness can be estimated using several methods, including Fourier spectral analysis of the thermal noise of the trapped particle position, or method based on equipartition theorem. The principles of the trap calibration and experimental results are presented.
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Iodine stabilized He-Ne laser for testing of laser interferometers
Petrů, František ; Lazar, Josef ; Zemánek, Pavel
The iodine-stabilized He-Ne lasers are the wavelength standard for metrology of lengths in mechanical engineering and microelectronics today. The high accuracy of the frequency of this standard predetermines this laser to be the fundamental etalon for laser interferometry. In the contribution, the basic properties of iodine-stabilized He-Ne lasers designed for the wavelength calibration of lasers for laser interferometry are discussed. In addition, some measurements of the vacuum wavelength of the single-frequency lasers of a novel type stabilized to the so called central maximum of the output power used as a source of laser radiation in the interference measuring system LOS are presented.
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Laser Optics and Technology in the Institute of Scientific Instruments of AS CR Brno
Petrů, František ; Pokorný, Pavel ; Lazar, Josef ; Stejskal, Alois ; Zemánek, Pavel
Research and development is oriented to new principles of frequency stabilisation using various physical phenomena. In this field special types of frequency stabilised lasers including He-Ne iodine-stabilised laser etalons at 633 nm were built. For this purpose the technologies of special laser tubes and absorption cells were developed. High-sensitive electronic systems for frequency stabilisation were designed and constructed and computer based measurement evaluation technique was developed. An important role among our activities plays thin film deposition technology, i.e. design of interference filters and production of individual pieces or small batches of elements according to specifications. Optical multilayers are produced by electron beam evaporation.
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Využití opticky zachycené sondy pro studium velmi slabých interakcí na molekulární úrovni - přehled
Zemánek, Pavel ; Jonáš, Alexandr
A micron-sized dielectric particle confined in a laser trap can be employed as a probe for the measurement of forces in the range from piconewtons to hundreds of piconewtons. Thus, if a biological system of interest (e.g. DNA molecule, single myosin or kinesin molecule, cell membrane) is attached to such a probe, its mechanical and dynamical properties (elasticity, viscosity, forces associated with movement) can be studied during its interaction with the environment with unprecedented resolution. This article introduces the basic principles of the laser trapping and force measurement and illustrates on several examples the great potential of the light-based force transducer for exploiting non-invasively the dynamics of molecular systems
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