Demonstration of a narrow-divergence x-ray laser in neonlike titanium

We report an observation of soft-x-ray lasing in Ti, at 326.5, based on recent experiments conducted on the Glass Development Laser (1.054 m) at the Laboratory for Laser Energetics and the Nova laser (0.53 m) at Lawrence Livermore National Laboratory. This Ti laser, which has been identified as a 3p3s transition in Ne-like Ti, is unusual in several ways; the J=01, 3p3s transition is observed to be the dominant laser line in a Ne-like spectrum, the laser output has a very narrow divergence, and lasing is observed only in experiments where the main optical pulse is preceded by a low-intensity prepulse. We describe the experimental results and present evidence that suggests the gain is enhanced by resonant photopumping of the Ne-like Ti 2p4d transitions by 3s2p C-like and 3d2p N-like Ti lines, which results in lasing on the 3p3s transitions in Ne-like Ti.