KULTŪROS PAVELDAS, TAUTINĖ VALSTYBĖ IR GLOBALIZACIJA: TARPUSAVIO RYŠIAI IR ĮTAKOS

Straipsnyje aktualinamas politinės galios vaidmuo konstruojant kolektyvinį tapatumą per kolektyvinę atmintį. Teoriniu lygmeniu siekiama „sukabinti“ tris aspektus: globalizacines dabartinį laiką determinuojančias tendencijas, nacionalinę valstybę kaip homogeniškai „įsivaizduojamą“ visuomenę ir kultūros paveldą kaip istorinę realybę ir bendruomenes homogenizuojantį veiksnį. Teorine šių trijų elementų tarpusavio ryšių analize siekiama paneigti prielaidą, kad kolektyvinė atmintis ar kolektyvinis tapatumas yra tik fikcija, ideologinis totalitarinis konstruktas, ir kad objektyviai egzistuoja tik individuali atmintis, kurią pats individas socialiai konstruoja

Diffraction-free subwavelength-beam optics

Diffraction is a fundamental property of light propagation. Owing to this phenomenon,light diffracts out in all directions when it passes through a subwavelength slit.This imposes a fundamental limit on the transverse size of a light beam at a given distance from the aperture. We show that a subwavelength-sized beam propagating without diffractive broadening can be produced in free space by the constructive interference of multiple beams of a Fresnel source of the respective high-refraction-index waveguide. Moreover, it is shown that such a source can be constructed not only for continuous waves, but also for ultra-short (near single-cycle) pulses. The results theoretically demonstrate the feasibility of completely diffraction-free subwavelength-beam optics, for both continuous waves and ultra-short pulses. The approach extends operation of the near-field subwavelength-beam optics, such as near-field scanning optical microscopy and spectroscopy,to the "not-too-distant" field regime (0.5 to about 10 wavelengths).Comment: 4 figure

Optical twists in phase and amplitude

Light beams with helical phase profile correspond to photons having orbital angular momentum (OAM). A Laguerre-Gaussian (LG) beam is an example where its helical phase sets a phase-singularity at the optical axis and forms a ring-shaped transverse amplitude profile. Here, we describe a unique beam where both phase and amplitude express a helical profile as the beam propagates in free space. Such a beam can be accurately referred to as an optical twister. We characterize optical twisters and demonstrate their capacity to induce spiral motion on particles trapped along the twisters' path. Unlike LG beams, the far field projection of the twisted optical beam maintains a high photon concentration even at higher values of topological charge. Optical twisters have therefore profound applications to fundamental studies of light and atoms such as in quantum entanglement of the OAM, toroidal traps for cold atoms and for optical manipulation of microscopic particles.V.R.D. has been funded partially by the Australian National University – Office of the Vice-Chancellor. D.P. and J.G. acknowledge financial support from the Danish Technical Scientific Research Council (FTP)

Long distance Bessel beam propagation through Kolmogorov turbulence

Free space optical communication has the potential to transmit information with both high speed and security. However, since it is unguided it suffers from losses due to atmospheric turbulence and diffraction. To overcome the diffraction limits the long distance propagation of Bessel beams is considered and compared against Gaussian beam properties. Bessel beams are shown to have a number of benefits over Gaussian beams when propagating through atmospheric turbulenc

Aberration-free ultra-thin flat lenses and axicons at telecom wavelengths based on plasmonic metasurfaces

The concept of optical phase discontinuities is applied to the design and demonstration of aberration-free planar lenses and axicons, comprising a phased array of ultrathin subwavelength spaced optical antennas. The lenses and axicons consist of radial distributions of V-shaped nanoantennas that generate respectively spherical wavefronts and non-diffracting Bessel beams at telecom wavelengths. Simulations are also presented to show that our aberration-free designs are applicable to high numerical aperture lenses such as flat microscope objectives

Covariant Lagrange multiplier constrained higher derivative gravity with scalar projectors

We formulate higher derivative gravity with Lagrange multiplier constraint and scalar projectors. Its gauge-fixed formulation as well as vector fields formulation is developed and corresponding spontaneous Lorentz symmetry breaking is investigated. We show that the only propagating mode is higher derivative graviton while scalar and vector modes do not propagate. Despite to higher derivatives structure of the action, its first FRW equation is the first order differential equation which admits the inflationary universe solution.Comment: Physics Letters B published version. LaTeX 12 page

Ultrafast laser micro-nano structuring of transparent materials with high aspect ratio

Ultrafast lasers are ideal tools to process transparent materials because they spatially confine the deposition of laser energy within the material's bulk via nonlinear photoionization processes. Nonlinear propagation and filamentation were initially regarded as deleterious effects. But in the last decade, they turned out to be benefits to control energy deposition over long distances. These effects create very high aspect ratio structures which have found a number of important applications, particularly for glass separation with non-ablative techniques. This chapter reviews the developments of in-volume ultrafast laser processing of transparent materials. We discuss the basic physics of the processes, characterization means, filamentation of Gaussian and Bessel beams and provide an overview of present applications

National symbols of Lithuania: the inherited or "invented” traditions?

The paper analyses the state symbols of the Republic of Lithuania. When analysing the practice of legitimation of state symbols in the Republic of Lithuania from 1987 to public discussions regarding the change of the status of the historical flag of the State of Lithuania to the state flag in 2007 (the documents of the Sąjūdis period, legal acts establishing the purpose of state symbols as well as the procedure for their use and publicist material), the author asks whether state symbol traditions have been inherited or “invented”. Having carried out the analysis, the paper concludes that the existing state symbols of Lithuania are declared to be the continuation of statehood traditions of the Grand Duchy of Lithuania (GDL) and interwar Lithuania in the official domain. Yet Vytautas Jarutis notes a tendency that the Lithuanian Heraldry Commission and some politicians more advocate the treatment of the state symbols of the current Republic of Lithuania as the sign of continuity of the GDL statehood tradition, although the majority of these symbols are the outcome of contemporary reconstruction. Thus, they cannot be considered to be the expression of inheritance or continuation of GDL traditions, but instead reconstruction or “invention” of traditions. The paper criticises the practice of legitimation of the state symbols of the Republic of Lithuania from 1990, coordinated by the narrow circle of specialists from the Lithuanian Heraldry Commission. The author notes a gap between the symbols that have been legitimated by the state and the symbols that “live” in the collective memory of society