Particle emission from polymer-doped water ice matrices induced by non-linear absorption of laser light at 1064 nm

Emission of PEG (polyethylene glycol) molecules and ions from an ice target induced by laser irradiation in the infrared (IR) regime at 1064 nm was studied. Matrices of 1% weight PEG flash-frozen solutions were used for polymer deposition with MAPLE (matrix-assisted pulsed laser evaporation). Even though linear absorption in defect-free water ice is two orders of magnitude larger at 1064 nm than 355 nm, the deposition rate and ion current density are much smaller for IR than for ultraviolet laser light. The similarity of results for both wavelengths indicates that non-linear absorption by electrons via optical breakdown is dominant.