- The aim of the present study is to clarify the time-dependent characteristics of the impulsive force generated by irradiating a laser pulse onto metallic and polymer materials. A Velocity Interferometer System for Any Reflector (VISAR) is employed to measure the acceleration driven by the laser ablation. The VISAR has two delay-lines that enable the velocity measurement in the range from 10 m/s to 100 m/s. The ablation impulse is inferred from the measured acceleration history. The influence of the ambient air on the ablation pressure is investigated for aluminum using a Nd:YAG laser (wavelength: 1064 nm, pulse energy < 1 J, pulse duration ~ 10 ns) and for a polymer material using a CO2 laser (wavelength: 1.06 mum, pulse energy < 10 J, pulse duration ~ 2 mus). The results of the preliminary experiments revealed the promising potential of the VISAR measurement.