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PL
Opisano współczesne dokonania Wydziału Fizyki Politechniki Warszawskiej w dziedzinie holografii klasycznej, cyfrowej i komputerowej, w odniesieniu do pojęcia dwuetapowego obrazowania zaproponowanego po raz pierwszy przez prof. Mieczysława Wolfkego. W szczególności omówiono osiągnięcia w metrologii i wyświetlaniu obrazów z wykorzystaniem fazowych modulatorów ciekłokrystalicznych, jak i nowatorskich materiałów optomagnetycznych.
EN
The article discusses the contemporary achievements of the Faculty of Physics of the Warsaw University of Technology in the field of classical, digital and computer holography in relation to the concept of two-stage imaging proposed for the first time by prof. Mieczysław Wolfke. In particular, the achievements in metrology and image display with the use of phase-only liquid crystal modulators and innovative opto-magnetic materials are discussed.
2
Content available Mieczysław Wolfke – od intuicji do innowacji
PL
Życiorys i sylwetka Mieczysława Wolfkego pojawiała się na łamach Postępów Fizyki już parokrotnie. Jednak jego postać, jedna z najważniejszych w historii międzywojennej fizyki w Polsce, prawie zanikła w powojennej świadomości fizyków. Nowy system polityczny oraz ogrom pracy związany z odbudową zniszczeń wojennych zarówno w sferze materialnej, jak i organizacyjnej tworzyły w latach 50. XX w. nowe wyzwania, odmienne od kultywowania pamięci o zmarłym w 1947 roku w Zurychu profesorze Politechniki Warszawskiej. A była to postać nie tylko wybitna, ale także niezwykle barwna.
EN
Biography and profile of Mieczysław Wolfke has already appeared in Postępy Fizyki several times. Nevertheless, it seems that his figure, one of the most important in the history of the interwar physics in Poland, almost disappeared in the post-war awareness of physicists. he new political system and the enormity of work related to the reconstruction of the war damage, both in the material and organizational area, created new challenges in the 1950s, different from cultivating the memory of the Warsaw University of Technology professor who died in 1947 in Zurich. However, he was not only an outstanding figure, but also an extremely colorful one.
EN
The possibility to detect defects in polyamide-aluminum composites with pure adhesive connection using holographic vibrometric non-destructive testing (NDT) was investigated. Clear differences could be observed in the phase of vibration patterns and amplitudes, registered with nanometric resolution, between a correct and a defective adhesive connection.
PL
Zbadano możliwość wykorzystania cyfrowej holograficznej wibrometrii – nieniszczącej metody testowania (NDT) – do wykrywania defektów połączeń adhezyjnych w kompozytach poliamidowo-aluminiowych. Zaobserwowano istotne różnice między uzyskanymi rozkładami drgań i ich amplitudami, mierzonymi z nanometryczną rozdzielczością, w wypadku próbek z połączeniem adhezyjnym bez defektu oraz z defektem.
4
Content available remote A holographic doctors’ assistant on the example of a wireless heart rate monitor
EN
Microsoft has created HoloLens glasses, a high-tech device used for holographic purposes, which is unique and superior to other available solutions. We present a new idea of a holographic assistant to doctors, using as an example a wireless patient data monitor. A dedicated application will be created to be used by doctors, allowing hands-free access to patient cards/data, reviewing of new/old examination results, and even the ability to work on real-time data. Doctors will be able to use this in the examination room, at a patient’s bedside, or in an entirely different location. Currently, analysis of patient data is done mostly by the doctor; however, huge progress in computer hardware performance and artificial intelligence (AI) algorithms has allowed the development of new methods used to analyze and classify patient examination results. In the same way that doctors learn and practice how to treat patients during their studies, algorithms can learn to spot abnormalities, allowing current technology and advanced AI algorithms to be joined in one high-tech solution that should provide initial assessment of patients’ health and give treatment guidance, if necessary.
EN
In this paper, the distortion of the reconstructed images of the propagating light pulse in transmission light-in-flight holography recording was analyzed. Based on the analysis model, for recording the wavefront more accurately, the optimized selection of relevant parameters was made. Furthermore, a cylindrical lens was introduced to correct the image distortion. Additionally, the light-in-flight recording of the wavefront changing during propagation was simulated.
PL
Przedstawiono ocenę jakości utwierdzenia beki wspornikowej metodą interferometrii holograficznej. Przedmiotem badań była belka o przekroju kwadratowym. W pomiarach zastosowano jedną z metod holografii optycznej zwaną metodą podwójnej ekspozycji. W wyniku interferencji fali przedmiotowej i fali odniesienia na materiale światłoczułym otrzymano obraz prążków interferencyjnych, na podstawie których wyznaczono przemieszczenia belki. Oceny jakości utwierdzenia belki dokonano na podstawie pomiaru kąta ugięcia w miejscu mocowania oraz bezwymiarowego współczynnika wprowadzonego przez autora.
EN
The estimation of the semi-beam restraint quality with use of holographic interferometry is presented. An object of investigations was a beam of square section. The double exposure method of optic holography was used for measurements. As a result of interference of the reference and main waves on light sensitive material, an image of interference striae is obtained, on the basis of which displacements of the beam can be determined. The estimation if the beam restraint quality was performed, basing of measurement of a deflection angle at the restraint point and the dimensionless coefficient introduced by the author.
PL
Przedstawiono pomiar przemieszczeń i naprężeń kół zębatych metodą interferometrii holograficznej. Przedmiotem badań było koło zębate. W pomiarach zastosowano jedną z metod holografii optycznej zwanej metodą podwójnej ekspozycji. W wyniku interferencji fali przedmiotowej i fali odniesienia na materiale światłoczułym otrzymano obraz prążków interferencyjnych na podstawie których wyznaczono przemieszczenia i naprężenia.
EN
The estimation of displacements and stresses of gear wheels with use of holographic interferometry is presented . A gear wheel was an object of investigations. The double exposure method of optic holography was used for measurements. As a result of the interference of the reference and main wave on a light sensitive material, an image of interferential striae was obtained. On the basis of this image, displacements and stresses of the studied object could be determined. The gear wheel tested is shown in Fig. 1, whereas the scheme of the test stand is presented in Fig. 2. Fig. 3 shows the load of the gear wheel. The standard beam is depicted in Fig. 4. Based on the interferometry striae shown in Fig.5, the displacements and stresses were determined. The loads at the stop of the tooth and at the pitch diameter are given in Tabs. 1 and 2. The stresses with the load at the stop are shown in Fig. 6. The stresses with the load on the pitch diameter are shown in Fig. 7. Based on the results given in Tabs.1 and 2, the displacements and stresses of the studied object were determined. In this work the holographic method and the method of finite elements were used.
EN
Available methods for room-related sound presentation are introduced and evaluated. A focus is put on the synthesis side rather than on complete transmission systems. Different methods are compared using common, though quite general criteria. The methods selected for comparison are: INTENSITY STEREOPHONY after Blumlein, vector-base amplitude panning (VBAP), 5.1-SURROUND and its discrete-channel derivatives, synthesis with spherical harmonics (AMBISONICS, HOA), synthesis based on the boundary method, namely, wave-field synthesis (WFS), and binaural-cue selection methods (e.g., DIRAC). While VBAP, 5.1-SURROUND and other discrete-channel-based methods show a number of practical advantages, they do, in the end, not aim at authentic sound-field reproduction. The so-called holophonic methods that do so, particularly, HOA and WFS, have specific advantages and disadvantages which will be discussed. Yet, both methods are under continuous development, and a decision in favor of one of them should be taken from a strictly application-oriented point of view by considering relevant application-specific advantages and disadvantages in detail.
PL
Przedstawiono propozycję pomiaru przemieszczeń stojanów maszyn elektrycznych metodą interferometrii holograficznej. Opisany poniżej przykład dotyczył pomiaru przemieszczeń powierzchni korpusów silników elektrycznych obciążonych siłami magnetycznymi. Siły te sprowadzone do tzw. sił naciągu magnetycznego powstają w wyniku niecentrycznego położenia osi wirnika względem osi stojana. W pomiarach zastosowano jedną z metod holografii optycznej zwaną metodą podwójnej ekspozycji. W wyniku interferencji fali przedmiotowej i fali odniesienia na materiale światłoczułym otrzymano obraz prążków interferencyjnych na podstawie których wyznaczono przemieszczenia poszczególnych punktów badanego obiektu.
EN
The estimation of displacements of electric machine stators with use of holographic interferometry is presented. The example described in the paper concerns measuring the displacements of the surfaces of electric motor housings while they were subjected to magnetic forces. The forces reduced to the so-called forces of magnetic tension are presents in the case of a non-central position of the runner axis relative to the stator axis. The double exposure method of optic holography was used for measurements. As a result of the interference of the reference and main wave on light sensitive material, an image of interferential strias is obtained on the basis of which the displaments of individual points of the studied object can be determined. The scheme of the test stand is shown in Fig.1. Position of the magnetic field relative to the investigated stator is shown in Fig. 2. Based on the interferometry striae shown in Figs.3 and 4, the stiffness of electric machine stator is presented. The asymmetry of deformation of the external stator surface is determined.
PL
Przedstawiono pomiar przemieszczeń i sił wewnętrznych w płytach kołowych metodą interferometrii holograficznej. Przedmiotem badań była płyta kołowa utwierdzona na obwodzie. W pomiarach zastosowano jedną z metod holografii optycznej zwaną metodą podwójnej ekspozycji. W wyniku interferencji fali przedmiotowej i fali odniesienia na materiale światłoczułym otrzymano obraz prążków interferencyjnych, na podstawie których wyznaczono przemieszczenia płyty oraz siły wewnętrzne. Oceny jakości utwierdzenia płyty dokonano na podstawie kąta ugięcia w miejscu mocowania oraz bezwymiarowego współczynnika wprowadzonego przez autora.
EN
The estimation of displacements and internal forces in circular plates with use of holographic interferometry is presented. An object of investigations was a circular plate restrained in the circuit. The double exposure method of optic holography was used for measurements. As a result of interference of the reference and main wave on light sensitive material, an image of interferential striae is obtained, on the basis of which displacements and internal forces of the studied object can be determined. The estimation of the plate restraint quality was performed basing on a deflection angle at the restraint point and the dimensionless coefficient introduced by the author. The bending moments are defined on the basis of the known displacements by means of differentiation. The scheme of the test stand is shown in Fig.1. The investigated object is presented in Fig.2. The diagrams of plate deflection, plate deflection angle and radial moment as a function of the radius are shown in Figs.3, 4 and 5.
11
Content available remote Holographic imaging with a nanometer resolution using compact table-top EUV laser
EN
Holographic 2D/3D imaging with nanometer resolution using short wavelength extreme ultraviolet (EUV) light is presented in this paper. Gabor's holograms were recorded with a highly coherent table top EUV laser with different numerical apertures demonstrating ultimately a spatial resolution of 46+/-2 nm, comparable with the illumination wavelength, in 2D holographic imaging. Three dimensional images were obtained from a single high numerical aperture hologram recorded in a high resolution photoresist and numerically reconstructed at different image planes, allowing numerical optical sectioning with a lateral resolution ∼170 nm and depth resolution of 2.4 μm. The holograms were recorded in a high resolution photoresist and digitized with an atomic force microscope. To assess the spatial resolution of the numerical reconstructions of the holograms a correlation method was used. The algorithm allows for simultaneous estimation of the resolution and the feature size of the image under analysis.
EN
In the paper, application of the digital holographic method for full field characterization of the beam generated by microlenses is considered. For this goal, the laboratory setup was designed based on Mach-Zehnder interferometry with the additional reference channel. The beam generated by a microlens was imaged by an afocal system and intensity distributions or interferograms (holograms) were registered by CCD camera. The digital holography using one image allows us to determine microlens parameters, i.e., focal length, aberrations, and shape. The optimum conditions to determine the surface shape of a microlens using holographic method have been found. We compare obtained results with geometrical and interferometric measurements. We show the advantage of digital holography for a shape microlens determination (improved accuracy), aberrations, and focal length (characterization facility). Through optimum refocusing, the digital holography gives more precise shape. The paper is accompanied with computer simulations and the experimental measurement data for geometrical, interferometric, and holographic methods.
13
Content available remote Optical data storage in LC cells
EN
Liquid crystal devices as a medium for holograms storage have been investigated. Long term memory effects in LC cells have been observed. Experiments proved that certain combination of insulating alignment layers has a major influence on the long term memory effect. Optimal liquid crystal cell construction allows us to achieve sufficient diffraction efficiency to record holographic patterns and to develop a re-writable holographic medium. The configuration of PVK and polyimide layers in LC cell construction with specific LC mixture was tested. The method of permanent and re-writable recording of optical data (holographic pattern) onto LC cells was achieved. However, the method of erasing recorded data was realized but mechanisms of this phenomenon are not clearly understood yet.
PL
Przedstawiono aktualny stan prac prowadzonych przez IEEE nad standardami ultraszerokopasmowych bezprzewodowych sieci osobistych. Scharakteryzowano podstawowe cechy zaproponowanych metod przetwarzania w warstwie fizycznej systemów oraz własności warstwy MAC. Omówiono wkład poszczególnych firm w rozwój systemów transmisji ultraszerokopasmowej oraz perspektywy wprowadzenia ich na rynek.
EN
The paper deals with 3-D display methods conventional, based on glasses and goggles as well autostereoscopic ones and holography. Principles of the new generation methods were discussed also, in particular merging 3-D imaging and holography.
EN
Using a two-wave mixing technique supplemented by the illumination of the second laser, we studied the dynamics of the photoinduced anisotropy in polyimide free-standing films doped by azo-dyes containing one or two N=N bonds.We have measured the characteristics of grating recording using a He-Ne laser source (_ = 632.8 nm) under influence of light coming from a cw YAG laser doubled in frequency (_ = 532 nm). The experiments in polyimide-Disperse Red 1 (4-[N-ethyl-N-(2-hydroxyethyl)]amino-4_-nitro-azobenzene) system revealed complex kinetics of photoinduced birefringence leading to grating recording and light self-diffraction. The two main processes were identified during the grating build-up in this high Tg polymer matrix. Preliminary results on possibility of dynamic color and polarization holographic recording in polyimide containing newly synthesized molecule having two N=N bonds 1,3 diamino-4-azo(4_-nitroazobenzene)benzene are also presented.
16
Content available remote The digital holograms projected onto LC cells
PL
W pracy przedstawiono rozważania dotyczące zapisu hologramów generowanych cyfrowo i projektowanych na przetworniki ciekłokrystaliczne. Na podstawie zaproponowanego modelu oraz danych doświadczalnych prześledzono wpływ konstrukcji przetwornika ciekłokrystalicznego, parametrów mieszaniny ciekłokrystalicznej oraz parametrów zapisu i odczytu hologramów.
EN
Holographic gratings formed by interfered He-Ne laser beams in cells with pure liquid crystal and dye-doped liquid crystal were described. The possibility of diffraction pattern generation in LC cells as a media was proven. Newly developed projection method of optoelectronic reconstruction of holograms expands possible applications of liquid crystals in holography. The presented works goal is to check the physical and optical parameters of liquid crystals mixtures in reference to set-up mentioned above. The relations between experimental results and theoretical needs of holographic reconstruction are discussed. Sample reconstructions of synthetic holograms are shown.
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