High-Density Micro-Drilling in Metal and PET Using Femtosecond Lasers

Microdrilling requirements vary strongly with material type, target hole diameter, pitch, allowable heat-affected zone, and throughput expectations. As a result, the best laser for one application may be the wrong tool for another depending on these competing requirements. This presentation examines how laser selection should be matched to the application by comparing high-density drilling needs in thin titanium foils and polyethylene terephthalate (PET).

The talk focuses on a practical engineering question: how do pulse duration, wavelength, beam diameter, repetition rate, and process architecture affect feature quality, array density, and manufacturing economics?

For thin titanium foils, femtosecond processing offers an attractive route where minimal collateral damage is required. Results of infrared and green femtosecond drilling are compared to show how wavelength and optical spot size influence dense-array performance.

This presentation will also compare how femtosecond (fs) lasers can be an advantage when machining stainless steel and PET but will also show where the optimal platform may be different. UV nanosecond lasers can support rapid drilling where some thermal compromise is acceptable.

About the presenter
Joshua Lessing is a principal laser applications engineer and project manager at OpTek Systems, with over 25 years of experience in laser-material interactions, micromachining, and advanced system development. His expertise spans ultrafast laser technologies, including femtosecond and picosecond platforms, with a focus on precision microfabrication, optical system design, and high-performance motion control integration.

Lessing has established and leads a state-of-the-art ultrafast laser applications laboratory, supporting both contract manufacturing and advanced R&D programs. His work involves process development and optimization across a broad range of materials, including carbon-based composites, metals, polymers, and semiconductor substrates, with emphasis on minimizing heat-affected zones and improving feature fidelity and throughput.

He has held senior engineering roles in the development of novel laser systems and processes, including contributions to green laser–assisted silicon etching and advanced photonics manufacturing technologies. With a background in applied physics and extensive industry experience, he brings a rigorous, data-driven approach to solving complex challenges in high-precision laser processing and system integration.