Trajectory-based interpretation of laser light diffraction by a sharp edge

In the diffraction pattern produced by a half-plane sharp edge when it obstructs the passage of a laser beam, two characteristic regions are noticeable. There is a central region, where it can be noticed the diffraction of laser light in the region of geometric shadow, while intensity oscillations are observed in the non-obstructed area. On both sides of the edge, there are also very long light traces along the normal to the edge of the obstacle. The theoretical explanation to this phenomenon is based on the Fresnel-Kirchhoff diffraction theory applied to the Gaussian beam propagation behind the obstacle. Here we have supplemented this explanation by considering electromagnetic flow lines, which provide a more complete interpretation of the phenomenon in terms of electric and magnetic fields and flux lines, and that can be related, at the same time, with average photon paths.Comment: 13 pages, 5 figure

The Influence of Serbian Literacy in Wallachia and Moldavia in the 14th and the 15th Century

In this paper we would like to examine the circumstances in which Serbian literacy reached the territory of the medieval principalities of Wallachia and Moldavia towards the end of the 14th and during the 15th century. The role of the hesychast Nikodim Grčić in that process is considered once again, particularly in light of the spiritual, cultural and artistic influences of the Mount Athos, where this spiritual mentor was closely associated with Isaiah. An insight into the structural, linguistic, and orthographic features of the Tetraevangelion connected with the territory of Wallachia reveals the physiognomy of its first scriptorium. Special attention is subsequently paid to reviewing the manuscripts of the Serbian rulers and ecclesiastical dignitaries that were connected in the 15th century with the books of the Moldavian monastery of Neamţ. In that context, relations will be examined between certain Serbian and Moldavian manuscripts in order to offer a more distinct picture of the role of Serbian literacy in the development of Moldavian literacy

Migration in Serbia: the Results of a Survey

Na području SR Srbije bez autonomnih pokrajina, krajem 1986. godine, završeno je prikupljanje podataka za anketno istraživanje pod nazivom »Društvena struktura savremenog jugoslovenskog društva«. Istraživanje je obavljeno u 101 opštini iz pet regiona ovog područja. Ukupan broj anketiranih ispitanika bio je 2798, u starosnom dobu od 18 do 65 godina, reprezentativno odabranih sa biračkih spiskova opština u kojima žive. Istraživanje, inače, ima jugoslovenski karakter budući da je na osnovu istog Upitnika, sprovedeno u svim republikama i pokrajinama. Kada je reč o društvenoj strukturi savremene Jugoslavije, što je bila osnovna tema ovog opsežnog istraživanja − istraživači su, s pravom, nastojali da ispituju ne samo značaj koji migracije stanovništva imaju u društvenim promenama i razvoju jugoslovenskog društva, već i eventualno postojanje njihovog uticaja na sastav i promene nekih činilaca strukture tog društva. Istraživanjem o kome je ovde reč, dobijeni su osnovni podaci koji mogu da ukažu na glavne odlike i pravce kretanja stanovništva na pomenutom području republike Srbije. Na osnovu odgovora ispitanika, dobijena je slika o dužini boravka ili nastanjenosti u istom mestu; zatim, o tome da li i kako zapošljavanje utiče na selidbe; kakva su, gledano po veličini i vrsti naselja iz kojih su se ispitanici iseljavali i, najzad, kako su tekla doseljavanja iz drugih republika, pokrajina i iz inozemstva.Na području SR Srbije bez autonomnih pokrajina, krajem 1986. godine, završeno je prikupljanje podataka za anketno istraživanje pod nazivom »Društvena struktura suvremenog jugoslavenskog društva«. Istraživanje je obavljeno u 101 općini iz pet regija ovog područja. Ukupan broj anketiranih ispitanika bio je 2798, u starosnoj dobi od 18 do 65 godina, reprezentativno odabranih sa biračkih lista općina u kojima žive. Istraživanje, inače, ima jugoslavenski karakter budući da je na osnovi istog Upitnika provedeno u svim republikama i pokrajinama. Kada je riječ o društvenoj strukturi suvremene Jugoslavije, što je bila osnovna tema ovog opsežnog istraživanja – istraživači su, s pravom, nastojali ispitivati ne samo važnost koju migracije stanovništva imaju u društvenim promjenama i razvoju jugoslavenskog društva, već i eventualno postojanje njezina utjecaja na sastav i promjene nekih činilaca strukture tog društva. Istraživanjem o kome je ovdje riječ, dobiveni su osnovni podaci koji mogu ukazati na glavne odlike i pravce kretanja stanovništva na spomenutom području Republike Srbije. Na osnovi odgovora ispitanika dobivena je slika o dužini boravka ili nastanjenosti u istom mjestu; zatim, o tome da li i kako zapošljavanje utječe na selidbe; kakva su, gledano po veličini i vrsti, naselja iz kojih su se ispitanici iseljavali i, najzad, kako su tekla doseljavanja iz drugih republika, pokrajina i iz inozemstva.On the territory of the Socialist Republic of Serbia, without autonomous provinces, at the end of 1986, collection of data for the questionnaire survey “The Social Structure of Contemporary Yugoslav Society“ was completed. The survey was conducted in 101 communes from five regions of this area. The total number of respondents was 2,798 in the age group of 18 to 65, taken as a representative sample from the electoral lists in which they live. The survey, otherwise, has a general Yugoslav character, in view of the fact that it was conducted on the basis of the same questionnaire in all the other republics and autonomous provinces. In regard to the social structure of contemporary Yugoslavia, which was the basic theme of this extensive survey – the researchers, justifiably, attempted to exa¬mine not only the significance that population migration has on the social changes and development of Yugoslav society, but also their possible influence on the content and changes of certain factors in the structure of this society. In the survey, basic data was collected which indicates the main traits and directions of population movement in the mentioned area of the Republic of Serbia. On the basis of respondents\u27 answers, a picture was provided of the length of stay and habitation in the same place; furthermore, whether or not and how employment effects migrations; what are, in regard to size and type, the settlements from which the respondents migrated and, finally, what was the migration flow from other republics, provinces and from abroad

Primena Husimijeve funkcije u vremensko-frekvencijskoj analizi signala

Husimi function originated in phase space formulation of quantum mechanics. This function appears naturally whenever simultaneous measurement of coordinate and impulse with maximal accuracy allowed by the Heisenberg uncertainty relation is performed on a given quantum state and it represents the probability distribution for simultaneous unsharp measurement of coordinate and impulse. Husimi function may analogously be defined for any pair of conjugated variables. In analysis of time varying signals these variables are time and frequency. In this paper we consider Husimi function in time-frequency space, we derive some properties of the function and give time-frequency analysis of some characteristic signals.U ovom radu razmotrena je Husimijeva funkcija na prostoru kanonski spregnutih promenljivih vreme-frekvencija. Izvedene su neke njene nove osobine koje su ilustrovane na nekoliko analitički zadatih signala. Pokazano je da se Husimijeva funkcija može koristiti pri vremensko-frekvencijskoj analizi signala

Primena Husimijeve funkcije u vremensko-frekvencijskoj analizi signala

Husimi function originated in phase space formulation of quantum mechanics. This function appears naturally whenever simultaneous measurement of coordinate and impulse with maximal accuracy allowed by the Heisenberg uncertainty relation is performed on a given quantum state and it represents the probability distribution for simultaneous unsharp measurement of coordinate and impulse. Husimi function may analogously be defined for any pair of conjugated variables. In analysis of time varying signals these variables are time and frequency. In this paper we consider Husimi function in time-frequency space, we derive some properties of the function and give time-frequency analysis of some characteristic signals.U ovom radu razmotrena je Husimijeva funkcija na prostoru kanonski spregnutih promenljivih vreme-frekvencija. Izvedene su neke njene nove osobine koje su ilustrovane na nekoliko analitički zadatih signala. Pokazano je da se Husimijeva funkcija može koristiti pri vremensko-frekvencijskoj analizi signala

The Case Study of the Serbian Copyist Ioan: on the Development of a Scientific Method for South Slavonic Palaeography

The present research aims to address the case study about the Serbian copyist anagnost Ioan through the use of the web-based repository. The same scribe's signature is observed in the manuscripts Dečani № 127 and № 119, which are also connected by the typology and a similar dating. The goal is to compare the distinctive features of both manuscripts and the handwriting of the 14th century scribes who contributed to the copying. In conducting this research, we will use a new descriptive scientific model, created and tested by the research project team

Combining size distribution spectrums of ambient aerosols using equivalent optical properties of nanosized particles – selected examples from the Bay of Kotor

Atmospheric aerosols in urban areas typically consist of particles of different diameters, which can range in size from a few nanometers to a few micrometers and can have a strong impact on human health [1,2]. This motivates the need to measure aerosol concentration accurately, but it is often also necessary to combine results from several instruments, with fundamentally different measurement principles. In this work, methods based on the measurement of the electrical mobility of particles, for the range of diameters from 10nm to 420nm, and the measurement of the equivalent optical diameter, for the range of diameters from 300nm to 10um, were used. Combining the overlapping region in two size distribution spectra can be used to infer equivalent optical properties of the ambient aerosol, and examples of measured and combined spectra in several urban hot spots in Bay of Kotor are analyzed in some detail. These examples will illustrate several aspects of urban aerosol properties not readily available in a typical regulatory monitoring setting, such as distribution of modes in number and mass concentration, as well as optical properties of measured aerosol. As the main result, examples of combining particle size spectrums are presented. In the process of combining the particle size spectra, it is possible to modify the distribution obtained by optical measurements by searching for the optimal value of the refractive index of the particles to obtain the best possible agreement with the size distribution obtained by measuring the electrical mobility. An equivalent refractive index as well as the equivalent shape factor of the ambient aerosol is obtained using Mie scattering theory as a theoretical framework [3]. The measurement results from the mobile monitoring campaign in Bay of Kotor in 2017 were used to elucidate the main principles of size spectrum combination, as well as to showcase diversity of equivalent optical properties of urban aerosols.XVI Photonics Workshop : Book of abstracts; March 12-15, 2023; Kopaonik, Serbi

Properties of the quantum state arising after the L-photon state has passed trough a linear quantum amplifier

We consider the system of N two-level atoms, of which N0 atoms are unexcited and N1 are excited. This system of N two-level atoms, which forms a linear quantum amplifier, interacts with a single-mode electromagnetic field. The problem of amplification of the L-photon states using such an amplifier is studied. The evolution of the electromagnetic field density matrix is described by the master equation for the field under amplification. The dynamics of this process is such that it can be described as the transformation of the scale of the phase space. The exact solution of the master equation is expressed using the transformed Husimi function of the L-quantum state of the harmonic oscillator. The properties of this function are studied and using it the average photon number and its fluctuations in the amplified state are found. © 2021, Editura Academiei Romane. All rights reserved

How does light move?: Determining the flow of light without destroying interference

Young's two-slit experiment constitutes the paradigm of quantum complementarity. According to the complementarity principle, complementary aspects of quantum systems cannot be measured at the same time by the same experiment. This has been a long debate in quantum mechanics since its inception. But is this a true constraint? In 2011, an astounding realization of this experiment showed that perhaps this is not the case, and the boundaries to our understanding of the quantum world are still far away