  We present an optical Kerr effect based time-gate with the collinear
incidence of the pump and probe beams at the Kerr medium, liquid carbon
disulfide, for ballistic imaging of the high-pressure fuel sprays. The probe
pulse used to illuminate the object under study is extracted from the
supercontinuum generated by tightly focusing intense femtosecond laser pulses
inside water, thereby destroying their coherence. The optical imaging spatial
resolution and gate timings are investigated and compared with a similar setup
without supercontinuum generation, where the probe is still coherent. And
finally, a few ballistic images of the fuel sprays using coherent and
incoherent illumination with the proposed time-gate are presented and compared
qualitatively.

Optics