Journal of Physical Chemistry B, Vol.101, No.35, 6955-6959, 1997
Laser-Induced Ablation Through Nanometer-Sized Tip Apertures - Mechanistic Aspects
Mechanisms for laser ablation of rhodamine dye thin films through nanometer-sized tip apertures commonly used for scanning near-field optical microscopy (SNOM) are discussed. Experiments and observations are presented that refute a mechanism based on transient tip elongation. Ballistic heat transfer is found to be insufficient for ablation of ionic solids such as rhodamine dyes. The most likely mechanism for creation of the nanoindentations on rhodamine films is photothermal ablation. It is further demonstrated that rhodamine is sublimating upon irradiation, is transported over considerable distances, and is redeposited. This may permit laser ablation through SNOM tips for nanosampling and nanoanalytical methods.