An amplified femtosecond laser system for material micro-/nanostructuring with an integrated Raman microscope

Abstract

In order to obtain new insights into laser-induced chemical material modifications, we introduce a novel combined approach of femtosecond pulsed laser-direct writing and in situ Raman microscopy within a single experimental apparatus. A newly developed scanning microscope, the first of its kind, provides a powerful tool for micro-/nanomachining and characterization of material properties and allows us to relate materials’ functionality with composition. We address the issues of light delivery to the photomodification site and show the versatility of the system using tight focusing. Amplified femtosecond pulses are generated by a Ti:sapphire laser oscillator and a chirped-pulse regenerative amplifier, both pumped by a diode-pumped frequency doubled neodymium-doped yttrium orthovanadate (Nd:YVO4) laser operating at 532 nm. Results of Raman spectroscopy and scanning electron microscopy images of femtosecond laser micro-/nanomachining on the surface and in the bulk of single-crystal diamond obtained from first trials of this instrument are also presented. This effective combination could help to shed light on the influence of the local structure fluctuations on controllability of the laser processing and the role of the irradiation in the ablation processes ruling out possible imprecisions coming from the use of the two independent techniques