The laser ablation process, a well-known form of laser-metal interaction, can form a plasma plume above the metal surface, which results in the production of radio frequency (RF) and optical emission, i.e. electromagnetic radiation. This thesis divides into two main parts. In the first section, the design and development of novel multi-messenger in-process techniques is examined for the reception of this radiation. The second half of the thesis concentrates on the analysis of the recorded data in order to correlate this data with post-process morphological data on the ablated metals.
This multi-messenger approach comprises the simultaneous collection of Radio Emission Spectroscopy and Optical Emission Spectroscopy (RES-OES) data. The recorded data was analyzed and its correlation with post-process metrology of the ablated surfaces such as morphological characteristics, captured using a 3D Microscope, has been found. It was demonstrated that the RES-OES technique can perform a near-real-time evaluation of ablated metal morphological outcomes of the ablation such as cleanliness, the aspect ratios of ablated holes, the generation of surface debris, etc.
In addition, an in-process methodology was developed for measuring the spatter area and depth of the metal surface during pulsed laser ablation using the received RF power from the laser-metal plasma plumes. This study shows that RES-OES monitoring tools have the potential to provide non-contact, non-invasive, real-time process monitoring of the ablated region during laser ablation processing. It is worth noting that, based on this work, two patent applications have been filed and two articles have been published in peer-reviewed journals to date.