Characteristics of a hollow-cathode cw He–Cd–Hg laser

Abstract

We describe the O(α 0 ) constraints on the target space geometry of the N = (2, 1) heterotic superstring due to the left-moving N = 1 supersymmetry and U(1) currents. In the fermionic description of the internal sector supersymmetry is realized quantum mechanically, so that both tree-level and one-loop effects contribute to the order O(α 0 ) constraints. We also discuss the physical interpretation of the resulting target space geometry in terms of configurations of a (2 + 2)-dimensional object propagating in a (10 + 2)-dimensional spacetime with a null isometry, which has recently been suggested as a unified description of string and M-theory.

The dominant pumping mechanism of the 441.6 nm Cd II line in a three-colour hollow-cathode discharge laser

“…The maximum value is at the point where helium and cadmium pressures reach 20 and 0.1 Torr, respectively. This result is in good agreement with our data obtained in experiments with the 441.6 nm laser line in a HCD (Vainer et al 1983, Kalinchenko et al 1989.…”

“…Lasers like this would be put out into practice for colour graphical information analysis and synthesis, various multiwave devices and so on. To increase the laser output power of the red line to make the blue, green and red intensities approach correlation to natural white, Vainer et al (1983) successfully used a helium-cadmium-mercury mixture in a CW HCD laser to carry out effective lasing action on the blue and green lines of Cd II and on the strong red line (λ = 615 nm) of Hg II. Several energetically possible pumping mechanisms are known for every laser transition (Boychenko et al 1989); however, only a few of them give noticeable contributions at low pressures; namely, various kinds of collisions with electrons, charge transfer and Penning ionization.…”