As a unique optical medium, plasma is found to be promising in the generation and manipulation of ultrashort intense laser pulses, such as the backward Raman amplification, Brillouin amplification, plasma-based pulse compression, generation of mid-infrared few cycle pulses via frequency downshifting, generation and amplification of structured intense laser pulses. In this talk, we report our recent progress on this topic. In particular, the concept of forward Raman amplification is proposed, which enables one to generate few-cycle petawatt-class in a distance of sub-millimeter with high amplification efficiency [1].  The amplification of a Laguerre-Gaussian pulse with co-propagating Gaussian laser pulses is proposed and validated in three-dimensional particle-in-cell simulation. Efficient energy transfer from Gaussian lasers to the Laguerre-Gaussian pulse is possible with proper control of the laser phases [2]. Efficient generation of ultrashort high-power light sources in the mid-infrared (mid-IR) to terahertz (THz) range via photon deceleration in plasma wakes by using two laser pulses at different frequencies is proposed verified numerically [3]. The copropagation of two relativistic intense laser pulses with orthogonal polarization in a parabolic plasma channel is studied, where the pulses and their wakefields can spiral and oscillate around each other. This suggests a new way to control the coupling of two intense lasers in plasma for various applications, such as electron acceleration and radiation generation [4,5]. Finally, the possibility of laser pulse compression and focusing towards the lamda-cubic limit is discussed [6].
 

Plasma optics, ultrashort intense laser