The Creation of Micropatterns through the Femtosecond Laser Ablation of Diamond Materials

• Main Author: Parrish, Matthew D.
• Format: Others
• Published: Trace: Tennessee Research and Creative Exchange 2009
• Subjects: Materials Science and Engineering
• Online Access: http://trace.tennessee.edu/utk_gradthes/56

Laser systems that create nanometer and micrometer scale features on the surface of materials are important tools used by the scientific and industrial communities to develop novel applications and technology. The goal of the research presented in this thesis is to investigate the characteristics of a custom femtosecond micro and nano machining station that uses laser ablation to create features and to advance system capabilities. The improvements include programs that allow for a greater variety and complexity of features and patterns that are easily customized to specification. In this work, a titanium doped sapphire (Ti:S) laser oscillator and amplifier system operating at 800 nm and producing 200 fs pulses uses new designs to create features on the surface of two types of synthetic diamond samples: plasma enhanced chemical vapor deposited (PE-CVD) polycrystalline diamond and single crystal diamond grown by a high pressure, high temperature (HPHT) process. Several examples of new designs created by rotating and superimposing simple geometric shapes are presented as images acquired by a Scanning Electron Microscope (SEM). Included design improvements suggest that patterns with higher resolutions will experience a smoothing effect along jagged edges. The presented analysis of feature variation with power show that features created on single crystal diamond tend to be larger and deeper than those created on polycrystalline diamond at similar conditions. Overall, the measurements presented for both materials increase linearly with increasing power. Also, the designs are best emulated by features ablated at relatively low powers. Raman spectroscopy shows that neither the single crystal diamond nor the polycrystalline diamond undergoes graphitization due to either single pulse or high repetition rate femtosecond ablation processes.