The invention of the chirped pulse amplification technique by Strickland and Mourou in 1985 has boosted the peak power of ultrashort laser pulses to an unprecedented level, which have found broad applications in fundamental science, industry and medicine. However, such high power lasers are usually obtained at the near-infrared wavelength of about 0.8 micron. The extension to the mid-infrared band (2-20 microns) is of great interest to broader applications. At present, the generation of mid-infrared laser pulses based on conventional optical technologies is limited by the frequency bandwidth, energy gain, and damage threshold of the optical crystals, which make it challenging to achieve high-intensity low-cycle mid-infrared laser pulses.