Manipulation by Photoelectron Currents for the Generation of Terahertz Light Pulses
Abstract
Using the strong field approximation we calculate photoelectron momentum distributions generated in the interaction of low-frequency two-color laser fields with atomic gases. The field consists of an infrared linearly or circularly polarized pulse of intensity close to 1014W/cm2 and its second linearly polarized harmonic whose intensity does not exceed 10% of the fundamental. Our calculations aim to find a field configuration, which maximizes the photoelectron current left after the interaction. Such net currents result from asymmetries of photoelectron distributions in non-monochromatic coherent fields with fixed phases between the frequency components. We show that combining a circularly polarized intense pulse with a linearly polarized pulse of the second harmonic one could approach the highest possible asymmetry of the photoelectron distribution and therefore the highest value of the net current.
Keywords: terahertz radiation, strong-field ionization, photoelectron currents, strong field approximation
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