These wavelengths are desirable in order to achieve high enough electron recollision energies, which scales as λ 2, for the purpose of dynamic imaging of molecular structures 13, 14 or generating high energy broadband radiations 15. With the advancement of ultrafast laser technology, such as optical parametric chirped pulse amplification (OPCPA), the laser wavelength has been pushed longer into the mid-IR regime with λ > 3 μm 12. Most work has been done with 800 nm, the fundamental wavelength of Ti:Sapphire laser systems. The most important laser parameter for the recollision process is the wavelength λ. The core physical process underlying these phenomena is the so-called recollision process 9, 10, 11: An emitted electron, after being accelerated in the laser field for a fraction of an optical cycle, can be driven back by the oscillating laser field and recollide with its parent ion core. Interaction between intense laser fields (10 13–10 16 W/cm 2) and gas-phase atoms or molecules has led to many new physical phenomena, such as high harmonic generation (HHG) 1, 2, above-threshold ionization (ATI) 3, 4, 5, nonsequential double ionization (NSDI) 6, attosecond pulse generation 7, 8, etc.