Development of a lamp-pumped Cr : LiSAF laser operating at 20Hz for a terawatt CPA system

Author(s):Show less -

Samad, RE ; Nogueira, GEC ; Baldochi, SL ; Vieira, ND ; Kudryashov, AV ; Paxton, AH ; Ilchenko, VS ; Giesen, A ; Nickel, D ; Davis, SJ ; Heaven, MC ; Schriempf, JT

• Document type: Journal article
• Source: MEDICAL IMAGING 2007: PACS AND IMAGING INFORMATICS; v. 6101, p. 11-pg., 2006-01-01.

Abstract

We report here the development, construction and characterization of a flashlamp pumped Cr:LiSAF rod pumping cavity designed to minimize the thermal load on the crystal. The cavity is a close coupled one with 2 Xe lamps and absorptive filters between the lamps and the Cr:LiSAF rod, and is refrigerated with cooled water. A compact and stable (g(1)center dot g(2)=0.57) resonator was designed for lasers tests and gain medium characterization, and we expected to obtain operation at 20 Hz repetition rate. Nevertheless, the thermal load minimizing design was so successful that allowed laser operation up to 30 Hz with an average power of 20 W. When operating with a 10% transmission output coupler this laser exhibited an overall laser efficiency of 0.6% under 100 J electrical pumping, and a slope efficiency of 0.8%. Under these conditions, a maximum gain per pass of 1.5 was obtained, suitable for regenerative amplifiers. To increase the gain, the intracavity filters were substituted by glass plates, resulting in a gain per pass of 3.6, adequate for multipass amplifiers. In this configuration, and operating as a laser resonator, it showed a maximum overall efficiency of 2.81% under 88 J electrical pumping with a 25% transmission output coupler, and maximum output power of 18 W at 8 Hz. A study of the thermal load on the crystal was conducted by observation of the upper laser level lifetime, and we concluded that there are no noticeable accumulated thermal effects on the Cr:LiSAF emission. (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