Determination of Cr : LiSAF crystals ablation thresholds on the 20 ps regime using a diagonal scan

Author(s)

Samad, Ricardo E. ; Baldochi, Sonia L. ; Vieira, Nilson D., Jr. ; Hoffman, HJ ; Shori, RK ; Hodgson, N

• Document type: Journal article
• Source: MEDICAL IMAGING 2007: PACS AND IMAGING INFORMATICS; v. 6451, p. 8-pg., 2007-01-01.

Abstract

The usual method to determine the ablation threshold of solid samples by ultrashort laser pulses is done by focusing the laser beam on the samples surface by a known lens, requires the knowledge of all the geometrical parameters (lens focus, beam propagation parameters, beam quality, sample position), and a series of measurements for different pulse energies. We present here a simpler method for determining ultrashort laser pulses ablation threshold for solid samples. The method uses a focusing lens, and requires only the knowledge of the pulse power, employing a diagonal translation of the sample through the laser beam waist, resulting in a pattern etched on the sample surface. The ablation threshold value is obtained measuring only one dimension of this pattern and a straightforward mathematical relation, There is no need to know any other geometrical parameter of the laser beam or of the lens used. The technique was employed to determine the ablation threshold of pure and Cr doped LiSAF samples for 20 picoseconds pulses, and a dependence with the Cr concentration was observed. (AU)

• FAPESP's process: 00/15135-9 - Implementation of a terawatt laser system and its applications
• Grantee: Nilson Dias Vieira Junior
• Support Opportunities: Research Projects - Thematic Grants