Propagation of intense optical wavepackets
Controlling the propagation of intense optical wavepackets in transparent media is not a trivial task. During propagation, low- and high-order non-linear effects, including the Kerr effect, multiphoton absorption and ionization, lead to an uncontrolled complex reshaping of the optical wavepacket that involves pulse splitting, refocusing cycles in space and significant variations of the focus. We have found, both numerically and experimentally, that intense, abruptly autofocusing beams in the form of accelerating ring-Airy beams are able to reshape into non-linear intense light-bullet wavepackets propagating over extended distances, while their positioning in space is extremely well defined. These unique wavepackets can offer significant advantages in numerous fields such as the generation of high harmonics and attosecond physics or the precise micro-engineering of materials and the remote generation of secondary sources, like THz. More information in:
- Panagiotopoulos, D. G. Papazoglou, A. Couairon, and S. Tzortzakis, "Sharply autofocused ring-Airy beams transforming into nonlinear intense light bullets",
Nature Communications 4, 2622 (2013)
Laser-plasma based THz emitters
Laser-plasma based THz emitters offer broad radiation bandwidth, high output pulse energy and immunity to high power damage. Various excitation wavelengths and gases were explored to seek for a stronger THz wave emission from laser-induced plasmas, whereas few attempts were made for this purpose with artificially modulated exotic wave packets. Using abruptly autofocusing beam induced air-plasmas we achieved a more than 5-fold enhancement of the THz wave pulse energy compared to normal Gaussian beam induced plasmas under the same conditions and this at well controlled remote locations. This work is expected to inspire a new direction for controlling THz radiation from laser-induced plasma and pave the way to THz remote spectroscopy, which is considered critical for both homeland security and environmental monitoring. More information in:
- Liu, A. D. Koulouklidis, D. G. Papazoglou, S. Tzortzakis, and X.-C. Zhang, "Enhanced terahertz wave emission from air-plasma tailored by abruptly autofocusing laser beams,"
Optica 3, 605-608 (2016)