Long channel formation in transparent dielectrics by femtosecond laser pulses under axicon focusing

Summary form only given. Among many other applications, femtosecond laser sources have opened a new possibility for precise and controlled modification of the irradiated material structure due to reduction of heat propagation effects at the laser energy deposition. In these experiments, tight laser focusing in the bulk or on the surface of a solid-state material is typically used to provide a needed energy concentration. In this report we present the results of a study on axicon focusing of femtosecond pulses with a moderate intensity inside transparent dielectrics to produce elongated structures in a modified material. We demonstrate interaction regimes with formation of unique solid-state material modifications in the form of channels of a micron-size diameter and the aspect ratio as large as 10/sup 4/.