Studies of crystalline paramagnetic holmium(3+), thulium(3+), and chromium(4+) lasers and Q-switches

Crystalline paramagnetic {dollar}rm Hosp{lcub}3+{rcub}, Tmsp{lcub}3+{rcub},{dollar} and Cr{dollar}sp{lcub}4+{rcub}{dollar} lasers and Q-switches were studied with spectroscopy and laser-pumped method. Spetroscopy of {dollar}rm Hosp{lcub}3+{rcub}, Tmsp{lcub}3+{rcub},{dollar} and Cr{dollar}sp{lcub}4+ {rcub}{dollar} doped crystals were studied with absorption spectra, cross sections, and fluorescent lifetime. Laser-pumped Ho:YAG up-conversion processes were described with experiments and models. Laser-pumped and flashlamp-pumped new Tm{dollar}sp{lcub}3+{rcub}{dollar} lasers were discussed. Laser-pumped Cr{dollar}sp{lcub}4+{rcub}{dollar}:YAG lasers and Cr{dollar}sp{lcub}4+{rcub}{dollar}:YSO Q-switches were described.; Absorption spectra of {dollar}rm Hosp{lcub}3+{rcub}, Tmsp{lcub}3+{rcub}{dollar}, and Cr{dollar}sp{lcub}4+{rcub}{dollar} doped crystals were measured. The stimulated emission cross section of Ho:YLF at 2050 nm (extraordinary) is {dollar}1.47 times 10sp{lcub}-20{rcub}{dollar} cm{dollar}sp2{dollar} and that at 2067 nm (ordinary) is {dollar}0.433 times 10sp{lcub}-20{rcub}{dollar} cm{dollar}sp2{dollar}. The fluorescent lifetimes of Cr{dollar}sp{lcub}4+{rcub}{dollar}:YAG varied from about 4.03 {dollar}mu{dollar}s at T = 80{dollar}spcirc{dollar} C.; Ho:YAG up-conversion processes were studied by using a Tm:YAG laser pump excitation at 2.01 {dollar}mu{dollar}m. The emissions at 558 nm and 760 nm ({dollar}sp5{lcub}rm S{rcub}sb2{dollar}), 670 nm ({dollar}sp5{lcub}rm F{rcub}sb5{dollar}), and 930 {dollar}mu{dollar}m ({dollar}sp5{lcub}rm I{rcub}sb5{dollar}) 1220 nm ({dollar}sp5{lcub}rm I{rcub}sb6{dollar}) were determined.; Er:glass laser pumped Er,Tm:YAG 2.01 {dollar}mu{dollar}m laser and ruby laser intercavity pumped Tm:YLF 2.30 {dollar}mu{dollar}m laser were demonstrated.; Flashlamp pumped cascade Tm:YAG 2320 nm and 2014 nm lasers were also demonstrated. The stimulated emission cross section of Tm:YAG at 2014 nm is {dollar}0.222 times 10sp{lcub}-20{rcub}{dollar} cm{dollar}sp2{dollar} based on absorption spectra and that at 2320 nm is {dollar}0.53 times 10sp{lcub}-20{rcub}{dollar} cm{dollar}sp2{dollar} based on cascade laser threshold.; Nd:YAG laser pumped Cr{dollar}sp{lcub}4+{rcub}{dollar}:YAG 1.4 {dollar}mu{dollar}m lasers were described with long-pulse pumping and Q-switched extracavity pumping. Cr{dollar}sp{lcub}4+{rcub}{dollar}:YSO was used for the first time to provide a saturable absorber Q-switch for the ruby laser. Single output pulse operation (100 mJ and 27 ns duration) with efficiencies relative to the free-running laser operation of 25-30% was routinely obtained.; The future directions of Ho{dollar}sp{lcub}3+{rcub}{dollar} up-conversion as well as laser action and Q-switching in {dollar}rm Hosp{lcub}3+{rcub}, Tmsp{lcub}3+{rcub},{dollar} and Cr{dollar}sp{lcub}4+{rcub}{dollar} were discussed.