Gregg H. Rosenblatt

Tm 3+ :YLF laser continuously tunable between 2.20and 2.46 μm

Room-temperature, continuous-wave laser action at 2.3 microm corresponding to the (3)H(4)-(3)H(5) transition in Tm(3+)- doped YLF is achieved. Output powers of 200 mW and a slope efficiency of 15% have been obtained for a pump power of 2 W at 0.78 microm. In addition, continuous tunability of this laser from 2.20 to 2.46 microm is obtained.

Continuous-wave mode-locked 2-μm Tm: YAG laser

Continuous-wave mode-locked operation of a 2-μm Tm: YAG laser is demonstrated. Stable, transform-limited pulses of 35-ps duration have been generated at a repetition rate of 300 MHz, with an average output power of 70 mW

Improved Ti:sapphire laser performance with new high figure of merit crystals

The continuous-wave (CW) laser performance of Ti:Al/sub 2/O/sub 3/ crystals with high figure of merit is described. Using a 0.1% Ti:Al/sub 2/O/sub 3/ crystal (FOM=1000), output powers of 3.5 W at 800 nm are obtained, pumping with a 9.6 W argon ion laser operating multiline. Continuous tunability of the CW Ti:Al/sub 2/O/sub 3/ laser extending from 665 to 1070 nm is also demonstrated for a 5 W pump power. >

Spectroscopic characterization of Nd-doped SrGdGa3O7 as a diode pumped laser host

Single crystals of Nd(3+):SrGdGa3O7 (SGGM) have been grown and characterized as candidate crystals for improved diode pumped lasers. The width of the 809 nm absorption in this disordered oxide crystal is 8 nm FWHM. The fluorescence lifetime of the 4F3/2 - 4I11/2 transition at 1.06 micron is 245 microsec. Dopant levels of 4 percent Nd have been achieved while maintaining high optical quality material.

Characterization of growth, spectroscopy, and laser properties of rare-earth-doped disordered oxides

Single crystals of three Nd3+-doped disordered oxides have been grown and characterized as candidates for improved diode-pumped solid state lasers. These hosts include one melilite, SrGdGa3O7 (SGGM), and two gallogermanates, La3Ga5GeO14 (LGG) and its isomorph La3Ga5SiO14 (LGS). Spectroscopic properties such as absorption and emission bandwidth, fluorescent lifetimes, and emission cross-sections are included. Laser properties of the 4F3/2 - 4I11/2 transition at 1.06 microns have been measured.

Continuous-wave 1.94-μmTm:CaY 4 (SiO 4 ) 3 O laser

Continuous-wave laser emission at 1.94 μm is reported in Tm:CaY4(SiO4)3O at room temperature with Ti:sapphire laser pumping at 790 nm. Pump thresholds of 100 mW and slope efficiencies of 32% have been achieved. The 3H6–3H4 pump absorption peak of 6% Tm:CaY4(SiO4)3O is six times stronger than the 3H6–3H4 pump absorption peak of 6% Tm:YAG.

Continuous Wave 3.4 µm Er:YLF Laser

Continuous-wave laser emission at 3.41 μm from an erbium-doped LiYF4 crystal (Er:YLF) at 77 K is reported. Operation of this 4 - level laser is based on the Er3+ 4F9/2 - 4I9/2 transition. An output power of 12 mW and a slope efficiency of 2% have been achieved.

Diode-pumped 2- and 3-um solid state lasers

Broadly tunable cw laser emission is demonstrated at room temperature in the 1.85 - 2.15 micrometers and 2.20 - 2.45 micrometers regions from Tm:YALO solid-state laser with 795 nm diode laser pumping. Also efficient cw laser operation at room temperature is demonstrated from the Er3+ in a garnet host at 2.8 microns, which is resonantly pumped with the 970 nm diode laser, resulting in a laser slope efficiency of 36%.

Diode pumped solid state mid-IR lasers for medical applications

The spectral region between 2 and 3 microns is of particular interest for medical applications because of the water absorption bands near 2 and 3 microns which lead to strong laser-tissue interactions. Recently we have tuned the tripositive thulium rare earth ion so that it can generate laser wavelengths over the spectral regions between 1.85 to 2.15 microns and between 2.20 to 2.37 microns continuously. Both laser systems, which operate CW, can be resonantly pumped with AlGaAs laser diodes operating at 785 nm. There has also been some interest in employing the 2 micron laser in a Q-switched mode. The thulium ion, however, has a low cross-section for the 2 micron transition so that efficient Q-switched operation has not been achieved in this ion. The traditional approach to the diode-pumped 2 micron laser has been to utilize crystals doped with both thulium and holmium ions. The thulium ion absorbs the pump radiation from AlGaAs diode lasers, while the laser transition takes place on the holmium transition at 2.1 microns which has a higher stimulated emission cross-section.<<ETX>>

Continuously tunable 2.3 /spl mu/m Tm:GSGG laser

For efficient operation of the Tm/sup 3+/ 2.3 /spl mu/m /sup 3/H/sub 4/-/sup 3/H/sub 5/ laser transition, a suitable host with low multiphonon decay rates, such as Gd/sub 3/Sc/sub 2/Ga/sub 3/0/sub 12/ (GSGG), is desirable. Continuously tunable, CW, room temperature laser operation of this transition is demonstrated for Tm:GSGG. Broadband tuning is obtained from 2.20-2.37 /spl mu/m.<<ETX>>