A Ti:sapphire tube laser pumped with dense plasma emission and internal spectrum conversion

Abstract

A Ti:sapphire hollow-tube laser has been pumped with annular plasma emission from a hypocycloidal pinch-plasma (HCP).1 The plasma color temperature was approximately 1 eV. The hollow of the Ti:sapphire tube was filled with dye solution for spectrum conversion2 from the near-uv to 490-nm pump band of Ti laser. These new ideas for improving the laser pumping efficiency were experimentally demonstrated. The operating conditions of the HCP were the following: The input electrical energy to HCP was 3.57 kJ, argon fill gas pressure 90 Torr, and Coumarin 503 dye as the spectrum converter. The pump pulse had a halfwidth of 13µs and a rise time of 2µs. The dimensions of the laser cavity were cavity length 295 mm, gain length 150 mm. Ti:sapphire crystal was in a hollow tube 150 mm long, its outer diameter 10 mm with a wall thickness of 3 mm, leaving a 4-mm diameter hole inside (Fig. 1). The untuned laser output was ≈ 45 mJ at λc =841 ± 4 nm and its temporal halfwidth was 0.35µs. Figure 2 compares the laser output with an without the internal spectrum converter solution as a function of the reflectance of the output coupler.