THEORETICAL-STUDY OF THE PROPERTIES OF A MODULATED FAST-FLOW CO2-LASER

The dynamic behaviour of a CO2 laser subject to modulation of its oper ational parameters is studied using an internally consistent formulati on of the well-known reservoir equations [K. Smith, R.M. Thomson, Comp uter modeling for gas lasers, Plenum, New York, 1978]. The use of prac tically inaccessible physical quantities is avoided leading to a trans parent set of equations describing the main properties of the temporal behaviour of the laser. The model is then applied to a variety of ope rational modes of the laser ranging from CW lasing to cavity dumping u sing a resonant reflector. In all these cases, and despite the simplif ications made to render the problem tractable for desktop computation, realistic results are obtained for such practically relevant quantiti es as electro-optic conversion efficiency (CW), peak power (Q-switched ), pulse repetition rate and duty cycle limitations (electrically puls ed) among others. This leads us to believe that the formulation of the equations given - based on extensive experimental and theoretical exp erience summarised in [S. Sazhin, P. Wild, C. Leys, D. Toebaert, E. Sa zhina, J. Phys. D 26 (1993) 1872-1883; S. Sazhin, P. Wild, E. Sazhina, M. Makhlouf, C. Leys, D. Toebaert, J. Phys. D 27 (1994) 464-469; M. S piridonov, C. Leys, D. Toebaert, S. Sazhin, E. Desoppere, P. Wild, S.M .P. McKenna-Lawlor, J. Phys. D 27 (1994) 962-969; D. Toebaert, P. Muys , E. Desoppere, IEEE J. Quantum Electron. 31 (10) (1995) 1774-1778; D. Toebaert, P. Muys, E. Desoppere, J. Phys. D 29 (7) (1996) 1910-1916.] - grasps the overall kinetics of the molecular discharge and can be r eliably used to at least predict upper limits to the laser's performan ce. (C) 1997 Elsevier Science B.V.