Optical breakdown in transparent media with adjustable axial length and location

Abstract

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.

Cavitation dynamics and directional microbubble ejection induced by intense femtosecond laser pulses in liquids

“…At low input energies and/or small input focusing angles, we indeed observe cavitation dynamics similar to those reported in Ref. [19], i.e., the formation of an elongated bubble that then contracts and disappears. However, at high ( 10-30 deg) focusing angles and relatively high input energies ( 10 μJ), that are therefore some one to two orders of magnitude higher than those used in previous studies, we observe a new cavitation regime characterized by rather remarkable bubble dynamics.…”

“…Such a configuration achieves much tighter focusing conditions with respect to the axicon-focusing used in, e.g., Ref. [19]. At low input energies and/or small input focusing angles, we indeed observe cavitation dynamics similar to those reported in Ref.…”

“…Such pulses generate bubbles with very high sphericity, a condition that is often required to observe the desired effects, e.g., cavitation-induced luminescence, or for comparison with hydrodynamic models. Spatial beam shaping has also been employed for generating elongated, multiple, or even arbitrarily shaped bubbles [18][19][20][21].…”

Intraocular Pressure Study in Ex Vivo Pig Eyes by the Laser-Induced Cavitation Technique: Toward a Non-Contact Intraocular Pressure Sensor

“…The LIB phenomenon is the partial or complete ionization of a solid, liquid, or gas through thermal or electromagnetic excitation, producing a typical electron density (plasma) above 10 18 -10 20 e/cm 3 [15]. While laser-induced thermal breakdown occurs for continuous-wave (CW) or repetitive-pulse lasers in [16,17], optical breakdown occurs primarily for single short pulse exposures in the microsecond to femtosecond time regime [18][19][20]. In both cases, LIB in liquids generates cavitation bubbles, shock waves, and luminescence.…”

Applications of femtosecond Bessel beams to laser ablation

“…Since the intensity maximum is strongly localized over a distance that exceeds the Rayleigh range of Gaussian beams by orders of magnitude, they have attracted a tremendous interest in both linear and nonlinear optics. These beams have been successfully used in the field of all-optical manipulation, and their unique properties of self-reconstruction and stability under nonlinear propagation in dielectrics have made them ideal candidates for highly localized and controlled energy deposition in transparent materials [2][3][4][5][6].…”