HHG from the instantaneous electronic response of the Kerr media on its pathway to create attoseconds and zeptosecond pulses and on the road to 10 nm XUV

The presentation reports on Higher Harmonic Generation (HHG) and ultrafast pulse creation depending on the instantaneous electronic Kerr response of media. A fundamental electromagnetic (EM) theoretical model is introduced as an alternative to the time-dependent Schrodinger equation with a semi-classical approach. The EM model is based on electronic self-phase modulation (ESPM) to explain odd higher Harmonic generation with its three salient features: slight decay of higher harmonics followed by harmonic plateau and cutoff frequency region on the number of odd HHG modes depending on the Kerr electronic response time of n₂ being less than a femtosecond. The only ansatz used for the EM model is based on the fact that light is a wave. The phase of the propagating light’s electric field is driven by itself through the index of refraction arising from χ³ and χ² to create HHG in the form of Bessel functions in time. The envelope of the laser pulse drives modes in the plateau and the cutoff region to lock these harmonic waves by Kerr mode locking to generate ultrashort pulses. Mode locking of 31 harmonics gives a 2.7 attosecond pulse while 311 harmonic modes can result in a short laser beam of 273 zeptosecond.