Extremely high-aspect-ratio ultrafast Bessel beam generation and stealth dicing of multi-millimeter thick glass

We report on the development of an ultrafast beam shaper capable of generating Bessel beams of high cone angle that maintain a high intensity hot spot with subwavelength diameter over a propagation distance in excess of 8 mm. This generates a high intensity focal region with extremely high aspect ratio exceeding 10 000:1. The absence of intermediate focusing in the shaper allows for shaping very high energies, up to Joule levels. We demonstrate a proof of principle application of the Bessel beam shaper for stealth dicing of thick glass, up to 1 cm. We expect that this high energy Bessel beam shaper will have applications in several areas of high intensity laser physics.