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Nanopositioning with detection of a standing wave
Holá, M. ; Hrabina, J. ; Číp, O. ; Fejfar, Antonín ; Stuchlík, Jiří ; Kočka, Jan ; Oulehla, J. ; Lazar, J.
A measuring technique is intended for displacement and position sensing over a limited range with detection of standing-wave pattern inside of a passive Fabry-Perot cavity. In this concept we consider locking of the laser optical frequency and the length of the Fabry-Perot cavity in resonance. Fixing the length of the cavity to e.g. a highly stable mechanical reference allows stabilizing wavelength of the laser in air and thus to eliminate especially the faster fluctuations of refractive index of air due to air flow and inhomogeneity. Detection of the interference maxima and minima within the Fabry-Perot cavity along the beam axis has been tested and proven with a low loss transparent photodetector with very low reflectivity. The transparent photodetector is based on a thin polycrystalline silicon layer. Reduction of losses was achieved thanks to a design as an optimized set of interference layers acting as an antireflection coating. The principle is demonstrated on an experimental setup.
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Detekce stojaté vlny uvnitř Fabry-Perotova rezonátoru
Holá, Miroslava
Tento příspěvek navazuje na projekt Interferometr kompenzující fluktuace indexu lomu vzduchu. Tato technika byla založena na diferenciálním uspořádání pro měření v atmosférických podmínkách. Rozvoj této měřící techniky vychází z oblasti nanometrologie. Fluktuace indexu lomu vzduchu jsou při interferometrickém měření hlavním zdrojem nejistot. Hodnota této nejistoty se pohybuje na úrovni 10-6 při nepřímém vyhodnocení z fyzikálních parametrů atmosféry.
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Nanopositioning with detection of a standing wave
Holá, Miroslava ; Hrabina, Jan ; Číp, Ondřej ; Fejfar, A. ; Stuchlík, J. ; Kočka, J. ; Oulehla, Jindřich ; Lazar, Josef
A measuring technique is intended for displacement and position sensing over a limited range with detection of standing-wave pattern inside of a passive Fabry-Perot cavity. In this concept we consider locking of the laser optical frequency and the length of the Fabry-Perot cavity in resonance. Fixing the length of the cavity to e.g. a highly stable mechanical reference allows stabilizing wavelength of the laser in air and thus to eliminate especially the faster fluctuations of refractive index of air due to air flow and inhomogeneity. Detection of the interference maxima and minima within the Fabry-Perot cavity along the beam axis has been tested and proven with a low loss transparent photodetector with very low reflectivity. The transparent photodetector is based on a thin polycrystalline silicon layer. Reduction of losses was achieved thanks to a design as an optimized set of interference layers acting as an antireflection coating. The principle is demonstrated on an experimental setup.
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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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