Optimizing energy deposition on corneal stroma for an application in laser femtosurgery

Abstract

Ultrashort laser pulses are very promising tools for performing accurate dissection in the eye, especially in the corneal stroma. The development of eye femtosurgery requires basic knowledge about laser-tissue interaction. One of the most significant parameters is the ablation threshold, the minimal laser energy per unit surface required for ablation. We present here measurements of the femtosecond laser ablation threshold as a function of the pulse duration for two cornea layers (epithelium and stroma) using optical damage diagnosis. Experiments have been realized with the INRS Ti:Sapphire laser (60 fs-5000 fs, 800 nm, 10 Hz). Our experimental results are fitted with a model for laser-matter interaction in order to determine some intrinsic physical parameters.Grant identification: CIHR, FQRNT, FRSQ Research in Vision Network, NSERC.

Influence of nonlinear and saturable absorption on laser lift-off threshold of an oxide/metal structure

“…The pulsed laser ablation threshold, laser-induced damage threshold (LIDT), and lift-off threshold fluences are used to describe the minimum laser energy per unit area which is required to remove (ablate) material from the surface. It is well known that the material removal threshold is dependent on many laser processing parameters, such as the number of pulses per spot, irradiation wavelength, [1], pulse duration [2], and polarization type [3]. The laser spot size on the sample and its related peak intensity's influence on the ablation threshold is rarely investigated in scientific literature, especially for metals [4].…”