Lasing on the D_2 line of sodium in helium atmosphere due to optical pumping on the D_1 line (up-conversion)

A new method is proposed to produce population inversion on transitions involving the ground state of atoms. The method is realized experimentally with sodium atoms. Lasing at the frequency corresponding to the sodium D_2 line is achieved in the presence of pump radiation resonant to the D_1 line with helium as a buffer gas.Comment: 4 pages, 4 figures, Late

A benchmarking study of the England and Wales water companies and Sydney Water Corporation Ltd for 1996-97

SIGLEAvailable from British Library Document Supply Centre-DSC:GPE/3216 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Explosive evaporation of Rb or K fractal clusters by low power CW radiation in the presence of excited atoms

In this paper we describe a new, spectacular, unpredictable effect of the explosive evaporation of metallic Rb or K fractal clusters, only in the presence of excited atoms stimulated by resonant CW laser radiation in a heat-pipe glass cell. Evaporation occurs at low laser-power density, in the presence of a buffer gas. The effect consists of the generation of optically thick, sharply localized alkaline metals vapour clouds propagating in the cell against the laser beam. These clouds are charged and exhibit a strong luminescence of Rb or K spectral lines. We believe that the explosive evaporation of metallic fractal clusters observed is explained by the laser excitation of alkali atoms. The excited atom collides into the surface of the clusters and transfers its internal energy to the surface locally. This energy greatly raises the temperature of this local part of the clusters surface, melts it and decreases the fractal surface area. Because, in general, any fractal cluster systems have a high surface energy, some of processes which leads to decreasing their surface area can liberate the surface energy. This energy increases the total temperature of the clusters and eventually leads to the thermal explosion of the cluster

Explosive evaporation of Rb or K fractal clusters by low power CW radiation in the presence of excited atoms

In this paper we describe a new, spectacular, unpredictable effect of the explosive evaporation of metallic Rb or K fractal clusters, only in the presence of excited atoms stimulated by resonant CW laser radiation in a heat-pipe glass cell. Evaporation occurs at low laser-power density, in the presence of a buffer gas. The effect consists of the generation of optically thick, sharply localized alkaline metals vapour clouds propagating in the cell against the laser beam. These clouds are charged and exhibit a strong luminescence of Rb or K spectral lines. We believe that the explosive evaporation of metallic fractal clusters observed is explained by the laser excitation of alkali atoms. The excited atom collides into the surface of the clusters and transfers its internal energy to the surface locally. This energy greatly raises the temperature of this local part of the clusters surface, melts it and decreases the fractal surface area. Because, in general, any fractal cluster systems have a high surface energy, some of processes which leads to decreasing their surface area can liberate the surface energy. This energy increases the total temperature of the clusters and eventually leads to the thermal explosion of the cluster

"White-light" laser cooling of high energy ion beams

'White-light' laser cooling of high energy ion beams confined in s storage ring is discussed. The cavity generating the frequency comb is described and the obtained spectra and performances given. The preliminary results on 'white-light' laser cooling of 7Li+ ions in a storage ring are shown

Frequency stabilization of a broad-band dye laser by light-induced drift

none7A new method for frequency locking of a broad-band laser based on light-induced drift is presented. The main advantages of the technique are: good stabilisation provided by sensitivity and good signal-to-noise ratio of the error signal; unnecessary dithering of the laser frequency; use of an atomic transition with low frequency drift. The method is well suited to broad-band applications because the light-induced drift effect can naturally integrate over a broad-band of frequencies (of the order of the Doppler width) to find the average. Tests carried out on Na immersed in a buffer gas of Ar, have allowed long-term frequency stabilisation of the central frequency of a 2.5 GHz-bandwidth dye laser.noneS. N. ATUTOV; R. CALABRESE; V. GUIDI; P. LENISA; S. PETRUIO; E. MARIOTTI; L. MOI AND A.M. SHALAGINS. N., Atutov; Calabrese, Roberto; Guidi, Vincenzo; Lenisa, Paolo; S., Petruio; E., Mariotti; L. MOI AND A. M., Shalagi

Generation of a frequency comb with a sharp edge of adjustable intensity and frequency

8sireservedA frequency comb is generated by successive frequency shifts of a single mode laser by an acousto-optic modulator coupled to a passive ring cavity. The cavity design and the laser-cavity coupling have a very high efficiency and allow for a perfect control of both the frequency and the intensity of the sharp edge. A second acousto-optic modulator can be used to double the comb bandwidth. The obtained spectrum is particularly suitable for laser cooling when a large velocity capture range is required as it is the case, for example, of ions confined in a storage ring.mixedATUTOV, S. N. ; BONAZZI, F. ; CALABRESE, R. ; GUIDI, V. ; LENISA, P. ; PETRUIO, S. ; MARIOTTI, E. ; MOI, L.Atutov, S. N.; Bonazzi, F.; Calabrese, R.; Guidi, V.; Lenisa, P.; Petruio, S.; Mariotti, E.; Moi, L