We present and experimentally validate a model describing the sensitivity of the tilt angle,
expansion, and the propulsion velocity of a tin micro-droplet irradiated by a 1 μm Nd: YAG
laser pulse to its relative alignment. This sensitivity is particularly relevant in industrial
plasma sources of extreme ultraviolet light for nanolithographic applications. Our model has
but a single parameter: the dimensionless ratio of the laser spot size to the effective size of
the droplet, which is related to the position of the plasma critical density surface. Our model …