59 research outputs found
Kaip šiandien lietuviškoje istoriografijoje keičiasi žvilgsnis į Lietuvos Didžiosios Kunigaikštijos epochą?
The aim of the article is to evaluate the methodological and ideological developments in the historiography of the epoch of the Grand Duchy of Lithuania in the comparative perspective of the last century. Methodologically, "the Golden Age" is exactly recorded at present in the Lithuanian historiography of the Grand Duchy of Lithuania. After reestablishing independence in 1990, Lithuanian historians refused the heritage of Soviet historiography, started integrating the Western theoretical discourse and have created a unique model of the development of the Grand Duchy of Lithuania in the European civilization, proposed by Edvardas Gudavičius. The receptions and transformations of this paradigmic model have been continuing until now in the transition from the political history to the history of society and everyday life, from an ethnolinguistically monoperspective to the liberal multicultural great narrative. Ideologically, the developments in the Lithuanian historiography of the Grand Duchy of Lithuania are analyzed on the basis of nowadays\u27 comparative studies of nationalism. This allowed to uncover the ethnocultural positions of interwar Lithuanian historians, the intuitionalism of the Soviet times and the constructivism of today, which implicate the cognitive step from "the plough of the nation" to the "Lithuanian europeism" in the Lithuanian collective consciousness
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
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