Influence of the resonator geometry on the output power of a laser with several active elements

Abstract

We study the effect of a single excluded site on the diffusion of a particle undergoing a random walk in a d-dimensional lattice. The determination of the characteristic function allows us to find explicitly the asymptotical behaviour of physical quantities such as the particle average position (drift) x (t) and the mean square deviation x 2 (t) − x 2 (t). In contrast to the one-dimensional case, where x (t) diverges at infinite times ( x (t) ∼ t 1/2 ) and where the diffusion constant D is changed due to the impurity, the effects of the latter are shown to be much less important in higher dimensions: for d 2, x (t) is simply shifted by a constant and the diffusion constant remains unaltered although dynamical corrections (logarithmic for d = 2) still occur. Finally, the continuum space version of the model is analysed; it is shown that d = 1 is the lower dimensionality above which all the effects of the forbidden site are irrelevant.

Performance of three-crystal 1800 watt CW Nd:YAG laser

“…Both sets of data show that the beam quality of this laser is comparable to that of some single rod lasers of 1/4 tO 1/3 the power of this laser. The ability to increase output power without altering beam quality by means of symmetrical multirod resonators has been discussed by Kushnir et al [3] and was recently investigated experimentally by Driedger et al [4]. Driedger et al confirmed that the beam quality remains virtually unchanged as second and third rods are added to a resonator so long as the rod/mirror geometry is optimized.…”