Ultrashort terahertz pulse generation and control using photoionization-induced nonlinearities in gases
Leibniz University, Germany
Intense, sub-cycle terahertz (THz) transients can be generated when strong optical pulses, containing two or more frequencies in the near infrared and above, are focused into a noble gas atmosphere to produce a plasma spot. The photoionization process is strongly nonlinear, making possible to produce a huge number of new frequencies, including also frequencies in THz range. We review our recent results which allow us to connect the pump wave shape to the generated THz transient, allowing to control THz signal properties as well as to increase its energy by more than one order of magnitude comparing to existing pump schemes.