Mapping the dynamical regimes of a SESAM mode-locked VECSEL with a long cavity using time series analysis.

The different dynamical regions of an optically-pumped SESAM mode-locked, long-cavity VECSEL system with a fundamental pulse repetition frequency of ~200 MHz are investigated. The output power, captured as 250 μs long time series using a sampling rate of 200 GSa/s, for each operating condition of the system, is analyzed to determine the dynamical state. A wavelength range of 985-995 nm and optical pump powers of 10 W-16.

Single-longitudinal-mode ring diamond Raman laser.

We demonstrate a single-longitudinal-mode ring diamond Raman laser, pumped by a tunable single-mode Ti:sapphire laser. Two methods to achieving unidirectional operation have been demonstrated: increasing gain for one direction using a reinjecting mirror and increasing loss for one direction using sum frequency mixing in BBO. Both methods result in a stable single-longitudinal-mode operation.

Tunable terahertz generation in the picosecond regime from the stimulated polariton scattering in a LiNbO crystal.

We demonstrate narrowband tunable terahertz generation from a picosecond LiNbO polariton laser, pumped by a CW mode-locked Nd:YVO picosecond laser. We generated up to 5.4 μW of terahertz output in untuned mode.

Two-Color, Two-Photon Imaging at Long Excitation Wavelengths Using a Diamond Raman Laser.

We demonstrate that the second-Stokes output from a diamond Raman laser, pumped by a femtosecond Ti:Sapphire laser, can be used to efficiently excite red-emitting dyes by two-photon excitation at 1,080 nm and beyond. We image HeLa cells expressing red fluorescent protein, as well as dyes such as Texas Red and Mitotracker Red. We demonstrate the potential for simultaneous two-color, two-photon imaging with this laser by using the residual pump beam for excitation of a green-emitting dye.

Ultrafast second-Stokes diamond Raman laser.

We report a synchronously-pumped femtosecond diamond Raman laser operating with a tunable second-Stokes output. Pumped using a mode-locked Ti:sapphire laser at 840-910 nm with a duration of 165 fs, the second-Stokes wavelength was tuneable from 1082 - 1200 nm with sub-picosecond duration. Our results demonstrate potential for cascaded Raman conversion to extend the wavelength coverage of standard laser sources to new regions.

25.5 fs dissipative soliton diamond Raman laser.

We have demonstrated a dissipative soliton diamond Raman laser that generates 25.5 fs pulses. Synchronously pumped by a 128 fs Ti:sapphire laser, the Raman cavity employed a pair of chirped mirrors to optimize the group delay dispersion, resulting in a Stokes field with 125 nm of spectral bandwidth from 840 to 965 nm.

Multiwavelength ultrafast LiNbO(3) Raman laser.

We present a multiwavelength ultrafast Raman laser based on lithium niobate which uses polariton scattering in combination with Raman scattering to selectively generate new wavelengths from a nanojoule-scale picosecond pump laser. Pumped by a 1064 nm pump laser, the system generates 1123 nm by stimulated polariton scattering (SPS) and 1140 nm by stimulated Raman scattering (SRS). Cascading of these intracavity fields generates 1155 nm and 1174 nm, as well as generating THz output.

Efficient diamond Raman laser generating 65 fs pulses.

We report a synchronously-pumped femtosecond diamond Raman laser operating at 890 nm with a slope efficiency of 32%. Pumped using a mode-locked Ti:Sapphire laser at 796 nm with a pulse duration of 194 fs, the bandwidth of the Stokes output was broadened to enable subsequent pulse compression to 65 fs using a prism-pair. Modelling results provide an understanding of the physical mechanisms involved in the Raman conversion of femtosecond pulses, supporting an in-depth characterization of these ultrashort pulsed lasers.

Ti:sapphire-pumped diamond Raman laser with sub-100-fs pulse duration.

We report a synchronously pumped femtosecond diamond Raman laser operating at 895 nm with a 33% slope efficiency. Pumped using a mode-locked Ti:sapphire laser at 800 nm with a duration of 170 fs, the bandwidth of the Stokes output is broadened and chirped to enable subsequent pulse compression to 95 fs using a prism pair. Modeling results indicate that self-phase modulation drives the broadening of the Stokes spectrum in this highly transient laser.

Spectral broadening in continuous-wave intracavity Raman lasers.

Spectral broadening of the fundamental field in intracavity Raman lasers is investigated. The mechanism for the spectral broadening is discussed and the effect is compared in two lasers using Raman crystals with different Raman linewidths. The impact of the spectral broadening on the effective Raman gain is analyzed, and the use of etalons to limit the fundamental spectral width is explored.

Highly efficient picosecond diamond Raman laser at 1240 and 1485 nm.

We present a highly efficient picosecond diamond Raman laser synchronously-pumped by a 4.8 W mode-locked laser at 1064 nm. A ring cavity was adopted for efficient operation.

Cascaded self-Raman lasers based on 382 cm(-1) shift in Nd:GdVO4.

We report quasi-continuous-wave, cascaded Nd:GdVO(4) self-Raman lasers based on a secondary Raman transition at 382 cm(-1) for which the Raman gain was estimated to be 0.7 cm/GW. Laser output was obtained in the near-infrared at 1108 nm, 1156 nm and 1227 nm.

Continuous-wave Watt-level Nd:YLF/KGW Raman laser operating at near-IR, yellow and lime-green wavelengths.

A Nd:YLF/KGW Raman laser has been investigated in this work. We have demonstrated CW output powers at six different wavelengths, 1147 nm (0.70 W), 1163 nm (0.

Continuous-wave VECSEL Raman laser with tunable lime-yellow-orange output.

We report a compact CW KGW Raman laser with intracavity nonlinear mixing, pumped by the intracavity field of a VECSEL. By temperature tuning an intracavity LBO crystal, we obtained two separate tunable emissions bands, namely 548.5 - 566 nm for sum-frequency-generation (SFG) of the fundamental and Stokes wavelengths, and 577.

Near-infrared and orange-red emission from a continuous-wave, second-Stokes self-Raman Nd:GdVO4 laser.

We report the first cw intracavity crystalline Raman laser operating at the second-Stokes wavelength. Approximately 950 mW emission is obtained at 1308 nm from a Nd:GdVO(4) self-Raman laser, with an overall (diode to 1308 nm) conversion efficiency of 6.8%.

Study of relaxation oscillations in continuous-wave intracavity Raman lasers.

We study the relaxation oscillations in a continuous-wave intracavity Raman laser both theoretically and experimentally. Analytic expressions for the relaxation oscillation frequency are derived from the rate-equations and are validated by experiments. We show that some important experimental parameters such as the effective Raman gain coefficient and intracavity Stokes loss can be determined simply by measuring the relaxation oscillation frequency versus pump power.

Short pulse eye-safe laser with a stimulated Raman scattering self-conversion based on a Nd:KGW crystal.

We present the results of a solid self-Raman laser based on a Nd:KGW crystal that is transversely pumped by laser diode bars. A beam of an eye-safe laser with a 31.8 mJ output energy and a 2.

[Support vector machine and optimized method for spectral analysis].

According to support vector machine based on the regularization theory, a small scale machine study theory was proposed to solve the problem of multi-gas analysis, which is mainly restricted by the lack of experimental samples. With its well nonlinear mapping ability, the training error was decided to be zero and global optimal parameters were obtained, hence the cross-sensitivity of spectrum is preferably eliminated. In multi-component gas analysis, the results show that the cross-sensitivity decreased to 1/81.