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SMV-2018-04: Planární mikrostruktury pro optické aplikace
Horáček, Miroslav ; Kolařík, Vladimír ; Matějka, Milan ; Krátký, Stanislav ; Chlumská, Jana ; Meluzín, Petr ; Král, Stanislav ; Fořt, Tomáš ; Oulehla, Jindřich ; Pokorný, Pavel
Vývoj planárních mikrostruktur pro optické aplikace a následná realizace vzorků metodou elektronové litografie a dalších technik. Projekt zahrnuje studium materiálů vhodných pro vytvoření planární mikrostruktury v kovové vrstvě s ohledem na dosažitelné rozlišení a splnění požadavků na absorbanci v dané aplikaci. Elektronová litografie je použita pro vytvoření požadovaného motivu v rezistové vrstvě, která slouží jako maska pro leptání kovové vrstvy různými technikami (mokré leptání, reaktivní iontové leptání). Součástí projektu je i sepsání technické dokumentace o vyvinutých postupech a připravených vzorcích.
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Optical binding of polystyrene particles in tractor beam
Damková, Jana ; Chvátal, Lukáš ; Oulehla, Jindřich ; Ježek, Jan ; Brzobohatý, Oto ; Zemánek, Pavel
The motion of a particle illuminated by a laser beam is usually driven by the photon flow due\nto the radiation pressure and therefore for particle trapping, one has to employ gradient forces. But in a tractor beam, objects are illuminated by the uniform light intensity and even so they can be pulled against the beam propagation. There have been developed several techniques how to create such a tractor beam. In our case, the tractor beam is created by two identical Gaussian beams that interfere under the defined angle. It creates the\nstanding wave, where in the transversal plane the particle is trapped by means of the gradient\nforce, but in the total beam propagation direction, the particle manipulation is driven by the non-conservative force. It is remarkable that this force can for the specific combinations of\nparameters pull the micro-particle against the beam propagation. This kind of behavior is\nbecause of the particle scattering where the majority of the incident photons is scattered in the forward direction and, based on the principle of action and reaction, the transfer of\nmomentum leads to a backward movement of the object. The pushing and pulling force is\nsensitive to the polarization of the laser beam, its incident angle and the particle size so this\ntechnique can be used for example for sorting of objects of different sizes.
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Lift-off technology for thick metallic microstructures
Krátký, Stanislav ; Horáček, Miroslav ; Meluzín, Petr ; Kolařík, Vladimír ; Matějka, Milan ; Oulehla, Jindřich ; Pesic, Z.
This paper deals with a method enabling the preparation of thick metallic microstructures on metal substrates. Such metallic microstructures can be used as a resolution samples to characterize various microanalysis techniques, such as X-ray fluorescence (XRF) or X-ray photoelectron spectroscopy (XPS). Moreover, the\npatterned samples could be used as anodes to characterize focusing properties of X-ray tubes for micro CT systems. Considering that the standard lift-off technique is designated for structures with the thickness of several hundred nanometers at most, we had to modify lift-off technique to be possible to use it for preparation of very thick metal layers (several microns) with spatial resolution of a few microns. The mask with the desired pattern for UV exposure was prepared by e-beam lithography. SU-8 photoresist was used for a lift-off because of its aspect ratio ability, process purity and high resistance to heating. We used a thin layer of PMMA under the SU-8 masking layer to guarantee the photoresist would lift-off correctly. Thick aluminum layer was deposited by thermal evaporation. The dependence of metal layer thickness as a function of required exposed\nline width was determined. The final lift-off process was carried out in acetone ultrasonic bath. Generally, this technology can be used for the evaporate deposition of various materials with several microns thick layer in\nmicron resolution.
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