Frequency resolved optical gating using the transient Kerr lens effect

We present a novel, to our knowledge, pulse characterization technique based on the transient Kerr lens effect, termed transient lens (TL) FROG. It employs a non-collinear pump–probe geometry combined with a coronagraphic detection scheme, enabling background-free signal acquisition. It is simple, is free from phase-matching constraints, and operates in both self-referenced and cross-referenced (two-color) configurations. The reliability of the self-referenced configuration is validated by comparing the retrieved temporal pulse profiles with those obtained using a commercial FROG device, showing excellent agreement. The cross-referenced configuration is validated through evaluation of the group-velocity dispersion, yielding a value consistent with the theoretical prediction. These results demonstrate that the technique performs reliably, provided the group-velocity mismatch between pump and probe pulses remains moderate—a limitation shared by all methods in this category. Owing to its simplicity and robustness, the TL-FROG approach is particularly well suited for nonconventional applications, such as ultraviolet (UV) pulse characterization.