Laser plasma optical device and method for generating ultra-short ultra-intense mid-infrared pulses

A laser plasma optical device, comprising:

• a laser system for outputting driving light pulses and signal light pulses;
• a vacuum target chamber for providing a vacuum environment for interaction of laser and matter;
• a gas target generating device disposed in the vacuum target chamber, the gas target generating device being used for generating gas and forming a plasma channel target along a propagation direction of a driving light pulse by a laser pre-pulse irradiation or by a high-pressure ionized gas;
• and
• a focusing element disposed in the vacuum target chamber,
• wherein the driving light pulse is focused onto the plasma channel target by the focusing element to generate a density-modulated plasma wake;
• after a predetermined delay time T, the signal light pulse is focused onto a leading edge region of a second plasma density cavitation bubble of the density-modulated plasma wake through the focusing element, so that frequency of the signal light pulse is red-shifted to generate a near-single-cycle mid-infrared pulse with relativistic intensity and single-pulse energy up to multi-millijoule.