相关论文: Directional infrared emission resulting from casca…
Population inversion on the 5D-6P transition in Rb atoms produced by cw excitation at different wavelengths has been analysed by comparing the generated mid-IR radiation at 5.23 um originated from amplified spontaneous emission and…
The mechanisms responsible for ultraviolet to mid-infrared light generation in sodium vapours two-photon excited with continuous-wave sub-100 mW power resonant laser radiation are elucidated from orbital angular momentum transfer of the…
We investigate frequency up-conversion of low power cw resonant radiation in Rb vapour as a function of various experimental parameters. We present evidence that the process of four wave mixing is responsible for unidirectional blue light…
We demonstrate how the orientation of the Rb cell can significantly affect the intensity and spectral characteristics of both the frequency up- and down-converted fields generated by nonlinear processes in Rb vapour. The efficiency of…
The nonlinear processes responsible for frequency up- and down-conversion of resonant low-intensity laser radiation in Rb vapour have been evaluated from the spatial and temporal properties of blue and mid-IR light resulting from wave…
Utilizing two-photon excitation in hot Rb vapor we demonstrate the generation of collimated optical fields at 420 nm and 1324 nm. Input laser beams at 780 nm and 776 nm enter a heated Rb vapor cell collinear and circularly polarized,…
The directional spiking infrared and ultraviolet emission from sodium vapors excited to the 4D5/2 level by a continuous-wave resonant laser pump, that constitute a novel feature of the cooperative effects, has been analyzed. Cascade…
Diffraction radiation (DR) is produced when a charged particle passes through an aperture or near a discontinuity in the media in which it is traveling. DR is closely related to transition radiation (TR), which is produced when a charged…
We report on spiking dynamics of frequency up-converted emission at 420 nm generated on the 6P3/2-5S1/2 transition in Rb vapour two-photon excited to the 5D5/2 level with laser light at 780 and 776 nm. The spike duration is less than the…
We study the angle-resolved spontaneous emission of near-infrared light sources in 3D photonic crystals over a wavelength range from 1200 to 1550 nm. To this end PbSe quantum dots are used as light sources inside titania inverse opal…
It is shown that when relativistically intense ultrashort laser pulses are reflected from the boundary of a plasma with a near-critical density, Doppler frequency shift leads to generation of intense radiation both in the high-frequency, up…
Diffuse interstellar bands comprise hundreds of absorption features in the ISM. Most DIBs are observed in the optical, but some are in the IR. We observed 76 early-type stars at R=50,000 and S/N ratios of several hundreds using CRIRES. We…
We have measured the near-infrared colors and the fluxes of individual pixels in 68 galaxies common to the Spitzer Infrared Nearby Galaxies Survey and the Large Galaxy Atlas Survey. Each galaxy was separated into regions of increasingly red…
We suggest a technique based on the transfer of topological charge from applied laser radiation to directional and coherent optical fields generated in ladder-type excited atomic media to identify the major processes responsible for their…
Spectral red-shifting of high power laser pulses propagating through underdense plasma can be a source of ultrashort mid-infrared (MIR) radiation. During propagation, a high power laser pulse drives large amplitude plasma waves, depleting…
We report the investigation of a collimated blue light generated in rubidium vapor due to the combined action of an ultrashort pulse train and a cw diode laser. Each step of the two-photon transition 5S - 5P$_{3/2}$ - 5D is excited by one…
The mid-infrared emission at the center of IRAS 21026+4104 is not that of a simple compact source, as one would expect from an isolated high mass protostellar object. Furthermore the central thermal infrared emission does not appear to be…
We report the transfer of phase structure, and in particular of orbital angular momentum, from near-infrared pump light to blue light generated in a four-wave-mixing process in 85Rb vapour. The intensity and phase profile of the two pump…
Observational data imply the presence of superluminal electric currents in pulsar magnetospheres. Such sources are not inconsistent with special relativity; they have already been created in the laboratory. Here we describe the distinctive…
We consider generation of diffusive radiation by a charged particle passing through a random stack of plates in the infrared region. Diffusive radiation originates due to multiple scattering of pseudophotons on the plates. To enhance the…