Generation av gigantiska halvcykelpulser av terahertzljus

Tidsperiod: 2017-01-01 till 2020-12-31

Projektledare: Vitaliy Goryashko

Finansiär: Vetenskapsrådet

Bidragstyp: Bidrag för anställning eller stipendier

Budget: 3 000 000 SEK

This project is to develop a novel concept of generation of quasi-half-cycle pulses of THz light with a field strength in the Volt/Ångström range (interatomic fields) and with variable polarization. The aims are to build a theoretical basis and perform a proof-of-principle experiment. The concept is based on using the frequency-chirped coherent spontaneous radiation from prebunched electron beams and controlling the slippage between electrons and the radiation field. Itcan be thought of as some analog of the mode locking in conventional lasers. The unique features of a coherent THz light source based on this concept are:it covers the spectral range from 5 to 15 THz, exceeding that of laser-based THz sources;polarization variable from linear to circular or elliptical;tunability of the central frequency and bandwidth;multi-kilohertz repetition rate;light carrying orbital angular momentum (multicycle wavefront).Few-cycle THz pulses allow engineering of new highly nonequilibrium states of matter such as THz light-induced superconductivity and, therefore, are of great interest for several users communities. At the very recent workshop on defining the science case for a soft X-ray laser at MaxLab in Lund, more than 50% of users requested a flexible few-cycle THz source for THz pump – X-ray probe experiments. A THz light source based on my concept greatly extends the capabilities of the existing ones and will be highly beneficial for time-resolved pump-probe experiments.