Ultrafast time-resolved spectroscopic imaging using femtosecond amplifying optical Kerr gate

Ultrafast time-gated imaging has gained wide interests due to potential applications such as visualization of ultrafast phenomena or objects in scattering media. The optical Kerr gate (OKG) has been providing useful tools for such applications in the picosecond region: (1) high sensitivity, (2) real time 2D imaging and (3) wide spectral bandwidth. To meet recent demand to realize higher spatial and temporal resolution, shortening of the opening time is necessary. However, there is an inherent trade-off between high sensitivity and fast response in conventional OKG, which limits its performance for time-resolved imaging. Jonusauskas et al. (1997) have developed a new setup (fast setup) to overcome this problem, which uses the optical Kerr effect in gain medium and two perpendicularly polarized pump pulses. They realized an amplifying OKG in the picosecond region using a dye solution. Minoshima et al. (1997) have applied femtosecond pulses to a fast setup to make possible a femtosecond amplifying OKG (fast OKG). In the paper, we demonstrate ultrafast time-resolved spectroscopic imaging using modification of the fast OKG setup and evaluation of its imaging performances.