A new integral equation for treating high-intensity multiphoton processes

Summary In the present paper we derive a new integral equation for the non-perturbative evaluation of transition matrix elements for high-intensity multiphoton processes. Our method will be partly based on the Kramers-Henneberger transformation. In the course of the development of our theory we shall relate our approach to previous investigations along similar lines. As a specific example we shall apply our integral equation to the problem of light scattering and present a multiphoton generalization of the Kramers-Heisenberg dispersion formula. We shall then apply this general formula to the study of higher-harmonic generation from a short-range potential with a single bound state, and evaluate the ratesR _n of then-th-order harmonic for a set of specifically chosen parameters. This work has been supported by the East-West Program of the Austrian Academy of Sciences under Project Nr. 45.174/1-46a/93 of the ?sterreichische Bundesministerium für Wissenschaft und Forschung.