GENERATION OF HARMONICS TREATED BY A NEW INTEGRAL-EQUATION METHOD

We derive a new integral equation for the nonperturbative evaluation o f transition matrix elements of multiphoton processes at high laser fi eld intensities. Our approach to the problem is partly based on the us e of die Kramers-Henneberger transformation. As a specific example, we apply our method to the generation of harmonics by an electron in a s hort range potential, supporting a single bound state. We evaluate the rates R2m+1 for the odd harmonics created in this process for a set o f specifically chosen parameters and we compare our results with prese ntly available experimental data.