Handling beam propagation in air for nearly 10-fs laser damage experiments

• We design and operate a laser damage test-bench in ultrashort laser regime.
• We measure the effects of self-focusing and air ionization on an ultrashort pulse.
• We calibrate the propagation of an ultrashort laser pulse in air.
• We measure the laser-induced damage threshold with 10 fs laser pulse.

We present the design and operation in air of a laser test-bench able to measure the laser-induced damage threshold of optical materials and components with ultrashort pulses down to nearly 10 fs pulse duration. Working in air environment brings the advantage of convenience and rapid diagnostics, provided that the laser beam is properly handled. As a preliminary step, a careful analysis of the spatial, spectral and temporal properties of the ultrashort laser beam is performed to characterize its propagation till the focal plane where the target is located. The results allow us to determine an upper limit of the incident energy below which the beam propagation is not affected by nonlinear effects, like Kerr effect or air ionization, which could skew the determination of laser-induced damage threshold. Finally, we demonstrate the capability of the laser test-bench by measuring the damage threshold of fused silica irradiated by single ultrashort pulses of nearly 10 fs pulse duration.