Optical breakdown in transparent media with adjustable axial length and location

We demonstrate a highly elongated (aspect ratio over 500:1) optical breakdown in water produced by a single pulse of a picosecond laser focused with a combination of an axicon and a lens. Locations of the proximal and distal ends of the breakdown region can be adjusted by modifying radial intensity distribution of the incident beam with an amplitude mask. Using Fresnel diffraction theory we derive a transmission profile of the amplitude mask to create a uniform axial intensity distribution in the breakdown zone. Experimentally observed dynamics of the bubbles obtained with the designed mask is in agreement with the theoretical model. A system producing an adjustable cylindrical breakdown can be applied to fast linear or planar dissection of transparent materials. It might be useful for ophthalmic surgical applications including cataract surgery and crystalline lens softening.