Pump-probe techniques using ultrafast lasers measure events on picosecond time  and are applied in such diverse fields as ultrafast spectroscopy, photo-acoustics, TeraHertz imaging, etc. 

In the traditional method, a single ultrafast laser generates the pump and probe pulses. A mechanical delay line shifts the two pulses in the time domain. This technique is very efficient for small measurement ranges, but may lead to a long acquisition time for longer ranges. The t-Pulse and Mikan ultrafast oscillators are efficient laser sources for this application.

Amplitude Systemes also offers a compact dual-oscillator ultrafast laser system, specifically designed for pump-probe measurements over time scales as long as 20 ns, with a sub-picosecond resolution. This system does not use any mechanical delay line, and allows for extremely fast acquisition time.

Courtesy University of Bordeaux

Surfaces Acoustic waves on a 250nm Tungsten film

Measurement range 20 ns 
Frame rate 1 Tera images per second