One difficulty with Cr4+ and Ti3+ lasers is the delay between pumping and lasing pulses. This delay poses problems for spectroscopy, which needs an excitation source that has high temporal stability with respect to the pumping pulse position. Now a Russian physicist has published results that point to an alternative excitation source: a diode-pumped LiF:F2+. The laser offers low-threshold reliability and tunability between 820 and 1200 nm. Because of the high gain of the F2+ center in LiF, there is almost no delay between the pumping and lasing pulses and none between pulses of different spectral components during lasing, according to a paper published by Valerii V. Ter-Mikirtychev of the General Physics Institute at the Russian Academy of Sciences in Moscow. The diode pumping technique provides high amplitude stability and high efficiency in a compact source. Ter-Mikirtychev's paper appeared in IEEE Photonics Technology Letters in October 1998.