Sharp edge broad-band lasers for "white-light" cooling in storage rings

We have developed broad-band laser sources which show a sharp edge in their spectra and are particularly suitable for ``white-laser' cooling of ions in storage rings. They allow for a very large velocity capture range by maintaining the same cooling rate allowed by the single mode lasers. A large fraction of the circulating ions are expected to be cooled both in coasting and bunched beams. The device, which does not use an active medium, can easily operate at any frequency from UV to IR spectral region. This revised version was published online in August 2006 with corrections to the Cover Date.     

Gas diffusion induced by resonance light field

The physical interpretation of a light-induced gas diffusion phenomenon is given and the experimental observation of this phenomenon in Na vapors is reported. It is established that Na vapors resonantly interacting with radiation can move along or against the direction of light propagation due to collisions with a buffer gas.     

First demonstration of “white-light” laser cooling of a stored ion beam

“White-light” cooling of an ion beam confined in a storage ring has been demonstrated at Test Storage Ring in Heidelberg. Measurements aimed at comparing “white-light” with single-mode laser cooling show that “white-light” cooling gives lower temperatures at higher ion densities both in a coasting and in a bunched beam. This revised version was published online in July 2006 with corrections to the Cover Date.     

Development of a broadband laser in the UV region

A frequency comb in the UV region with a bandwidth greater than 100 MHz is generated by successive frequency shifts of a single mode laser by an acousto-optic modulator coupled to a passive ring cavity. The obtained spectrum is particularly suitable for laser cooling when a large velocity capture range is required as in the case, for example, of ions confined in a storage ring. This revised version was published online in August 2006 with corrections to the Cover Date.     

Optical Relaxation Phenomena in a Rubidium Vapor Cell with an Antirelaxation Coating under Bichromatic Laser Irradiation

Journal of Experimental and Theoretical Physics - The excitation of long-term fluorescence by variously configured beams of bichromatic laser radiation in a rubidium vapor cell has been studied....     

Photoextraction of molecular gases from an organic polymer film

Photoextraction of various molecular gases from a polydimethylsiloxane (PDMS) polymer film has been studied. Change in the density of molecular gases has been measured as a function of the illumination duration, intensity and wavelength of light, and temperature of the coating. A linear dependence of the rate of photoextraction on the intensity of the incident light has been established. Similar to the photoelectric effect, photoextraction is absent in the long-wavelength spectral range down to 550 nm. The effect increases sharply in the short-wavelength spectral range below a threshold of about 550 nm. Photoextraction is absent at temperatures below the glass-transition temperature of PDMS (?125°C), at which, as is known, the bulk diffusion of molecular gases in the film is strongly suppressed. At long-term irradiation of the film, the number of photoextracted molecules decreases exponentially with time. This increase is accompanied by a long tail of a diffusion form. The results indicate that photoextraction has a nonthermal nature and demonstrate the important role of bulk diffusion in the process of light-induced extraction of molecules from the surface.     

Reflection and transmission of plane waves at the interface between anisotropic random discrete media

The Maxwell equations are solved for a random discrete medium using the single-scattering approximation and the condition of immersion in a maximally packed medium. The reflection and transmission factors of plane waves at the interface between vacuum and a random discrete anisotropic medium are determined. The calculated and experimental results on reflection and transmission of plane waves near the edge of a forest as an example of natural anisotropy of a random discrete medium are compared.     

A new salicin derivative from the stem bark of Populus davidiana

Phytochemical study on the BuOH-soluble fraction of the stem bark of Populus davidiana resulted in the isolation of a new salicin derivative(1),named davidianoside.The structure was elucidated on the basis of extensive physicochemical and spectroscopic analyses.