Producing isolated laser pulses in attoseconds made easier using two-color laser field

Producing isolated laser pulses in attoseconds made easier using two-color laser field: A number of research groups have recently generated isolated laser pulses as short as 80 attoseconds. However, their energy is still too low be used in practice, since the energy of the pump pulses is limited. High pump energy would induce high gas ionization such that the atoms hit by the pump pulses would be highly ionized, but this would prevent the whole process of re-collision. In addition, to guarantee reliable production of isolated attosecond pulses, the phase of the carrier envelope wave connected to the pump pulse needs to be stabilized, which requires an expensive and complicated process.

To circumvent these limitations, Takahashi and colleagues used a two-color laser field: a pump laser with an 800-nanometer wavelength superimposed on one of 1,300 nanometers. The combination of the two lasers allowed the generation of a higher harmonic spectrum without needing to stabilize the carrier envelope phase.

Crucially, they used conventional lasers that are readily available and inexpensive.