Newtonian Telescope Design for Stand-off Laser Induced Breakdown Spectroscopy

Laser induced breakdown spectroscopy (LIBS) works by shooting laser light onto an optical system that initially expands the beam through an expanding lens and then focuses it on the sample through a focusing lens. Focusing the laser on the sample creates a plasma emitting light. This light is then focused on an optical fiber, through a light gathering optical system, which is connected to a spectrometer, where the results can be analyzed. In this research a design of a stand-off LIBS device is introduced.

This research addresses a system that scans the environment, which means that the target distances vary. The system’s key components are a laser, lenses and mirrors to allow adjustments of the beam, to achieve ablation in the target sample, and the collection of emitted light from it. The importance of choosing the right components is significant in such optical setups where precision is of high
priority.
The research addresses a way to design a system that works as effectively as possible and gives high quality results regarding chemical composition of target material. The device is based on a Newtonian telescope model, whereas the target is to fit most of the optical components on the same optical axis. The results show that optically, such a setup is possible for a LIBS device. Results also show that the design of such a device allows parts to be made by additive manufacturing, as long as the optics are adjustable to maintain the precision.

LIBS is a growing technology which can be used for many applications. There are still some limitations to the technology such as coatings of mirrors and lenses to allow wider wavelengths to pass through or reflect.