On the tunability of energetic highly-elliptical higher harmonics generated by intense two-color counter rotating laser fields

Tunability of energetic highly-elliptical high-harmonics is demonstrated. Harmonics are generated in Ar gas, driven by intense two-color counter rotating laser electric fields, namely of the fundamental and second harmonic frequency. For the experiment a MAZEL-TOV-like device is used, combined with loose focusing geometry. By properly tuning the central frequency of the second harmonic, the central frequency of the extreme ultraviolet (XUV) high harmonic radiation is continuously tuned.