Ti:sapphire laser pumped by a frequency-doubled diode-pumped Nd:YLF laser

Transverse-pumping approach for a powerful single-mode Ti:sapphire laser for near infrared lidar applications

We present a design of a transversely pumped and powerful Ti:sapphire laser, suitable for laser remote sensing in the near infrared (NIR) spectrum. Examining multiple pump configurations revealed that transversal pumping of Ti:sapphire crystals with a Nd:YAG laser (532 nm) from one or two sides yields maximum output power. Together with an optimized bow-tie resonator setup, we were able to extract up to 3 W (30 mJ, 100 Hz) of narrowband NIR laser emission from a cuboid 50 mm long Ti:sapphire crystal. Beam quality and divergence were determined as Mx2=1.1, My2=1.7, φ_x=0.5mrad, and φ_y=0.8mrad. The spectral purity (seeded, P_seed≥170µW) was better than 99.8%. Additionally, we show a two-wavelength setup applicable to atmospheric water vapor lidar. The principle performance of this theory of operation suggests a good chance of scalability towards significantly enhanced power of future Ti:sapphire lasers.

Realization of compact Watt-level single-frequency continuous-wave self-tuning titanium: sapphire laser

Here, we present a compact Watt-level single-frequency continuous-wave (CW) self-tuning titanium:sapphire (Ti:S) laser, which is implemented using a three-plate Ti:S crystal as both a gain medium and frequency-tuning element. The thickness ratio of the three-plate Ti:S crystal is 1:2:4, of which the thinnest plate measured 1 mm. The optical axes lie on their own surfaces and parallel to each other. Based on the presented self-tuning crystal, a ring resonator is designed and built. The maximum wavelength tuning range of the single-frequency self-tuning Ti:S laser is 108.84 nm, as demonstrated experimentally by rotating the three-plate Ti:S crystal, indicating good agreement with theoretical prediction. To the best of our knowledge, this is the first study to report a single-frequency CW self-tuning Ti:S laser, which can provide a feasible approach for achieving a compact all-solid-state single-frequency CW-tunable Ti:S laser.

Frequency-doubled DBR-tapered diode laser for direct pumping of Ti:sapphire lasers generating sub-20 fs pulses

For the first time a single-pass frequency doubled DBR-tapered diode laser suitable for pumping Ti:sapphire lasers generating ultrashort pulses is demonstrated. The maximum output powers achieved when pumping the Ti:sapphire laser are 110 mW (CW) and 82 mW (mode-locked) respectively at 1.2 W of pump power. This corresponds to a reduction in optical conversion efficiencies to 75% of the values achieved with a commercial diode pumped solid-state laser. However, the superior electro-optical efficiency of the diode laser improves the overall efficiency of the Ti:sapphire laser by a factor > 2. The optical spectrum emitted by the Ti:sapphire laser when pumped with our diode laser shows a spectral width of 112 nm (FWHM). Based on autocorrelation measurements, pulse widths of less than 20 fs can therefore be expected.

Operation of a Ti:sapphire laser pumped by a 499-nm green laser

We report, for the first time, to our knowledge, the operation of a tunable Ti:sapphire laser pumped by a third-order Raman XeCl-H(2) laser system at 499 nm with a 60-ns pulse duration. The slope efficiency is 59% for this laser, producing pulses of 20-ns duration. The highest conversion-energy efficiency obtained is 41%, with an output energy of 1.2 mJ. The tuning range for a single set of cavity mirrors is 680-834 nm and is limited mainly by the mirror reflectivity. This study shows that a combined laser system based on a XeCl excimer laser can offer wavelength diversity.

Resonant frequency quadrupling of a mode-locked diode-pumped Nd:YLF laser

We report on a novel method of efficient frequency quadrupling of a mode-locked diode-pumped Nd:YLF laser to 262 nm in the ultraviolet region of the spectrum using two external ring enhancement cavities in series. With 6 W of pump power the mode-locked Nd:YLF laser produced 1 W of power incident into the first enhancement cavity. The fundamental has been resonantly frequency doubled using a crystal of lithium triborate with a conversion efficiency of 60% to produce 600 mW of usable mode-locked output at 523.5 nm. Fourth-harmonic radiation was generated by frequency doubling this green output in a second ring enhancement cavity using a crystal of beta-barium borate. Conversion efficiencies from green to ultraviolet of 11% have been achieved, producing a maximum usable average power at 262 nm of 42 mW in picosecond pulses.

Low-threshold, cw, all-solid-state Ti:Al(2)O(3) laser

A cw Ti:A1(2)O(3) ring laser with a threshold power of 119 mW is demonstrated. It provides a tunable source of single-frequency, diffraction-limited radiation that is suitable for injection seeding. The Ti:A1(2)O(3) laser is operated with a diode-laser-pumped, frequency-doubled, Nd:YAG laser as the sole pump source.

Broadly tunable high-power operation of an all-solid-state titanium-doped sapphire laser system

Broadly tunable and high-power operation of a titanium-doped sapphire laser is obtained with a diode-laser-pumped frequency-doubled Nd:YAG laser as the pump source. A maximum broadband (FWHM = 25 nm) output pulse energy of 720 microJ at 795 nm in a TEM(00) mode is obtained for 1850 microJ of energy of 532-nm pump light. A minimum pulse duration of 7 ns is obtained from a 40-mm-long cavity. With the use of an intracavity prism, the Ti:sapphire laser is tunable continuously over the 696-1000-nm spectral range (with three different mirror sets).