Picosecond vs Femtosecond: Are All Laser Desorption Ionizations Created Equal?

Abstract

With a three-dimensional (3D) momentum imaging technique, we investigated the laser desorption ionization dynamics initiated by both chirped picosecond and femtosecond pulses. 3D momentum images of desorbed ions from 2,5-dihydroxybenzoic acid (DHB), a common laser desorption matrix, were obtained for the first time. A striking difference was observed between the processes initiated by femtosecond and picosecond pulses. The lack of initial momentum in ions produced by femtosecond pulses suggests a suppression of plume formation, which can be exploited to increase the sensitivity of matrix-assisted laser desorption ionization.