Pump processes that produce upconversion laser emission in trivalent rare earth ion-doped gain media are described, and the performance of upconversion lasers pumped by these processes is reviewed. Sequential two-photon absorption upconversion, cooperative energy transfer upconversion and photon avalanche upconversion are discussed in relation to the production of visible laser emission. Using ...

A high-power 83 W cladding-pumped Tm3+-Ho3+-doped silica fiber laser is reported. Using bidirectional 793 nm diode pumping, a maximum slope efficiency of 42% was produced after a threshold launched pump power of 12 W was exceeded. The laser operated at wavelengths near 2105 nm with moderate beam quality, i.e., M2 approximately 1.5. Further power scaling of the fiber laser was limited by thermal...

A multi-wavelength laser is demonstrated using a dye-doped cholesteric polymer film whose reflection bandwidth is broadened with several oscillations. Due to the abrupt change of the density of state between oscillation peak and valley, each oscillation functions as a photonic band gap for generating a laser wavelength under the excitation of a pumping laser. As a result, a multiple wavelength ...

At the end of the millennium a continuous wave (cw) pumped atom laser remains to be experimentally demonstrated. The prototype atom lasers that have been operated have used rapidly pulsed or continuous output coupling, but lacked pumping of the trapped atom laser mode [1,2], as is needed for a cw laser system. Indeed, apart from simple rate equation descriptions, existing theoretical models do ...

A flashlamp-pumped dye laser was modified to produce 80mJ/pulse, narrowband output at 532 nm suitable for pumping of Raman active transitions of the major combustion species CO2, H2O, N2, and O2. Simultaneous measurements of multiple species were obtained in atmospheric pressure methane-air flames, demonstrating absolutely quantitative measurements of species mole-fraction. Comparisons with Q-s...

In order to achieve a continuous tuning of laser emission, the authors designed and fabricated three types of cholesteric liquid crystal cells with pitch gradient, a wedge cell with positive slope, a wedge cell with negative slope, and a parallel cell. The length of the cholesteric liquid crystal pitch could be elongated up to 10 nm, allowing the lasing behavior of continuous or discontinuous s...

At the end of the millennium a continuous wave (cw) pumped atom laser remains to be experimentally demonstrated. The prototype atom lasers that have been operated have used rapidly pulsed or continuous output coupling, but lacked pumping of the trapped atom laser mode [1,2], as is needed for a cw laser system. Indeed, apart from simple rate equation descriptions, existing theoretical models do ...