1.5-/spl mu/m emissions from laser-diode-pumped microchip Nd-doped solid-state lasers

Summary form only given. In the past decades, a wide variety of experimental laser materials and devices has been developed. Among them, the laser diode (LD) end-pumped microchip-type laser is the current device of choice. For Nd-doped lasers, as promising laser materials, there are three main manifolds for lasing transition. In the case of Nd:YAG, the 1.064 and 1.061 /spl mu/m transitions, /sup 4/F/sub 3/2//spl rarr//sup 4/I/sub 1/2/, provide the lowest threshold lasers for which the branching ratio of emission is highest. When the laser was cooled, the 1.839 /spl mu/m line and 0.946 /spl mu/m line could be observed while operation at 1.3 /spl mu/m also had been achieved. Similar ratios also have been reported in other Nd-doped lasers. Thus far, no emission of 1.5 /spl mu/m has been reported in Nd-doped lasers. On the other hand, high-energy modified lattice vibrations with 1400, 1700, and 2500 cm/sup -1/ have been reported for Nd in YVO/sub 4/. Under this condition, activated phonons may provide coherent scattering towards the regime of around 1.5 /spl mu/m, which has useful applications, such as communication and eye-safe long-distance range finding. We report the first observation of such emissions directly from the LD-pumped microchip Nd:YVO/sub 4/ laser as well as the LiNdP/sub 4/O/sub 12/ (LNP) laser.