Stable Color Center Laser in OH-Doped NaCl Operating in the 1.41–1.81 µm Region

Abstract

Over the past year we have been investigating a new color center laser in NaCl [1]. We tentatively attribute the laser action to a new type of color center, namely the F₂ ⁺ center stabilized beside an O^— ion. Optimum laser performance to date displays stable cw operation with tuning from 1.41 to 1.81 gm with a maximum cw output power of 1.25 W when pumped by a 9 W 1.06 μm Nd:YAG laser. The laser crystals can be stored for weeks at room temperature with no apparent degradation, however efficient operation requires that the crystal be cooled to 77 K during laser operation. The crystals are additively colored in a heat pipe, which partially explains the storage and operational stability of the center. In addition, modelocked pulses of 5 psec duration have been generated in a synchronously pumped arrangement, tunable from 1.47 to 1.73 μm with an average power of 450 mw at the peak of the tuning curve.