High-order harmonic amplitude modulation in two-colour phase-controlled frequency mixing
Max-Planck Institut für Quantenoptik, D-85748 Garching, Germany
2 Centre Lasers Intenses et Applications, Université de Bordeaux I F-33405 Talence Cedex, France
Accepted: 29 April 1999
Two-colour phase control of gas harmonic generation has been demonstrated using a 200-fs Ti:sapphire laser and its second harmonic. In the detection range covering the 7th to the 20th harmonic order, a modulation of up to 27% in the harmonic emission signal was observed by precisely varying the relative phase between the two colours. Simulations based on the single-particle response predict enhancement of the high harmonic efficiency by orders of magnitude for a given relative phase between the two colours.
PACS: 42.65.Ky – Harmonic generation, frequency conversion / 32.80.Rm – Multiphoton ionization and excitation to highly excited states (e.g., Rydberg states)
© EDP Sciences, 1999