Princip neođredenosti u klasičnoj mehanici: primjena na kolinearne sudare

Classical theory of collisions is formulated which also includes uncertainty principle. The theory is used for the calculation of transition probabilities in the collinear He-H2 collision, and the results are compared with quantum calculations. Very good agreement is found.Klasična teorija sudara formulirana je uz uvažavanje principa neodredenosti. Izračunali smo prijelazne vjerojatnosti za kolinearni sudar He-H2 i usporedili rezultate s kvantnim proračunima. Pronašli smo vrlo dobro slaganje

Omjeri grananja i vjerojatnosti prijelaza živina tripleta u vidljivom dijelu spektra

We have measured branching ratios of mercury visible triplet lines 404.7, 435.8 and 546.1 nm (73S1-63P0,1,2) by controlling the absorption. The absolute transition probabilities have been determined by using critically selected lifetime of the upper level and measured branching ratios.Mjereni su omjeri grananja spektralnih linija iz živina tripleta u vidljivom dijelu spektra: 404.7, 435.8 i 546.1 nm (73S1-63P0,1,2) i pritom je određivana apsorpcija u izvoru. Apsolutne vjerojatnosti prijelaza određene su upotrebom odabranog vremena života gornjeg nivoa i izmjerenih omjera grananja

Laserom inducirana fluorescencija stanja A 1Σu+ molekule Li2

By using several continuous wave (CW) single longitudinal-mode semiconductor laser diodes in the red spectral region, we have excited Li2 molecule from the X 1Σ g+ state to the A 1Σu+ state (transitions: (v " = 0, J " = 19) → (v\u27 = 4, J\u27 = 18); (v " = 1, J " = 9) → (v\u27 = 5, J\u27 = 10); (v " = 2, J " = 9) → (v\u27 = 10, J\u27 = 10)) and observed the fluorescence of the resonance A → X lines together with collision induced lines. Comparison with theoretical simulations shows a very good agreement. The use of two or three diode lasers is discussed in view of two- or three-step excitation of Li2 molecule to the higher Rydberg or ionized molecular states.Pomoću kontinuiranih jednomodnih lasera u crvenom dijelu spektra pobuđivali smo molekulu Li2 iz stanja X 1Σg+ u stanje A 1Σu+ (v " = 0, J " = 19) → (v\u27 = 4, J\u27 = 18); (v " = 1, J " = 9) → (v\u27 = 5, J\u27 = 10); (v " = 2, J " = 9) → (v\u27 = 10, J\u27 = 10)) i promatrali fluorescenciju rezonantnih A → Xprijelaza zajedno sa sudarom uzrokovanim prijelazima. Usporedba eksperimentalnih spektara s teorijskim simulacijama tih spektara pokazuje dobro slaganje. Diskutira se upotreba dva ili tri diodna lasera za trokoračno pobuđenje molekule Li2 u viša Rydbergova ili ionizirana stanja

Investigation Into the Effects of Laser Texturing on the Wettability of Ti-6Al-4V Alloy

Laser surface texturing is a technology that enables us to achieve very complex surface geometries. In this study, geometries created on the Ti-6Al-4V surface were in the form of parallel grooves. Those geometries were obtained by changing the laser beam speed and the number of passes (one or two). The effects of laser texturing on the roughness and the contact angle of Ti-6Al-4V surfaces on the first day and after 80 days were investigated. The results of this study indicate that the samples treated with two passes of the laser beam and at a lower speed scan show regularities of roughness profile geometry while other laser-treated samples do not. It is shown that the surfaces laser-textured with either one or two passes of the laser beam show no significant changes in the surface wettability after 80 days. The statistical test proves that there is a significant difference (level α = 0.05) between the contact angles on the untreated sample on the first day and after 80 days of treatment

Quantum holography with single-photon states

The retrieval of the phase with single-photon states is a fundamental and technical challenging endeavor. Here we report the first experimental realization of hologram recordings with heralded single-photon illumination and continuous observation of photon statistics. Thereby, we demonstrate the basic principle of holography with single-photon states which cannot be described with the classical wave theory. Under conditions with illumination more than 200 times weaker than the noise of the detector, a hologram (interferogram) recorded with a heralded single-photon source revealed an object not visible with non-heralded illumination and slightly higher intensity. The dramatic improvement in retrieval of amplitude and phase information achieved with the heralded single-photon source can be explained by the strong suppression of noise due to the nonclassical temporal correlation between twin photons and the small coincidence time window. The method could be useful for recording and retrieving of amplitude and phase information in the presence of strong noise, for covert imaging, and for imaging of photosensitive biological and material samples.Comment: 20 pages, 6 figures, 2 table

Linearity and Optimum-Sampling in Photon-Counting Digital Holographic Microscopy

In the image plane configurations frequently used in digital holographic microscopy (DHM) systems, interference patterns are captured by a photo- sensitive array detector located at the image plane of an input object. The object information in these patterns is localized and thus extremely sensitive to phase errors caused by nonlinear hologram recordings (grating profiles are either square or saturated sinusoidal) or inadequate sampling regarding the information coverage (undersampled around the Nyquist frequency or arbitrarily oversampled). Here, we propose a solution for both hologram recording problems through implementing a photon-counting detector (PCD) mounted on a motorized XY translation stage. In such a way, inherently linear (because of a wide dynamic range of PCD) and optimum sampled (due to adjustable steps) digital holograms in the image plane configuration are recorded. Optimum sampling is estimated based on numerical analysis. The validity of the proposed approach is confirmed experimentally