S. Chénais

Diode-pumped Yb:Sr(3)Y(BO(3))(3) femtosecond laser.

We have developed a diode-pumped Yb(3+)Sr(3)Y(BO(3))(3) (Yb:BOYS) laser generating 69-fs pulses, at a central wavelength of 1062 nm. This laser is mode locked by use of a semiconductor saturable-absorber mirror and emits 80 mW of average power at 113 MHz. This is, to our knowledge, the first mode-locked Yb:BOYS laser and the shortest duration obtained from an ytterbium laser with a crystalline host. The central wavelength can be tuned from 1051 to 1070 nm, for sub-100-fs pulses. We have also achieved an average power as high as 300 mW with pulse duration of 86 fs at 1068 nm.

Diode-pumped Yb:GGG laser: comparison with Yb:YAG

Abstract A diode-pumped ytterbium-doped Gd 3 Ga 5 O 12 (Yb:GGG) laser is reported for the first time. We report up to 4.2 W of CW laser power when pumping on the 971 nm absorption band with a 14 W fiber-coupled diode. The easy growth and the high thermal conductivity of Yb:GGG make it a challenger of Yb:YAG for high power applications. The efficiencies of these two crystals have been compared under the same pumping conditions, and turn out to be comparable.

Spectroscopy and efficient laser action from diode pumping of a new broadly tunable crystal: Yb 3+ :Sr 3 Y(BO 3 ) 3

The first demonstration of laser action in a Yb3+:Sr3Y(BO3)3 crystal is reported. This new material exhibits particularly broad absorption and emission bandwidths (6 and 60 nm, respectively) and hence is of particular interest for diode-pumped femtosecond and tunable laser sources. Efficient operation from diode pumping (1.4 W of cw laser power obtained with 3.6 W of diode pump power and as much as 3.4 W of peak power from high-power quasi-cw pumping) together with smooth tunability (over 50 nm FWHM) is reported. For the comparison, efficiency and thermal limitations of Yb:glass and Yb:Ca4GdO(BO3)3 have been investigated under the same conditions.

Apatite-structure crystal, Yb 3+ :SrY 4 (SiO 4 ) 3 O, for the development of diode-pumped femtosecond lasers

We report what is believed to be the first diode-pumped Yb(3+): SrY(4)(SiO(4)) (3)O laser. We investigate both the cw and the mode-locked regimes. In the cw regime an average output power of 1.05 W is demonstrated for 3.6 W of incident pump power. In the femtosecond regime a pulse duration of 94 fs for an average power of 110 mW is obtained at a central wavelength of 1068 nm. This is, to our knowledge, the first femtosecond mode-locked oscillator made with an Yb-doped apatitelike crystal. These properties are related to the unique spectroscopic properties of Yb(3+) ions in this atypical apatite-family crystal.

Thermal lensing measurements in diode-pumped Yb-doped GdCOB, YCOB, YSO, YAG and KGW

A Shack–Hartmann wavefront sensor was used to measure thermal lensing in diode-end-pumped Yb-doped GdCOB, YCOB, YSO, YAG, and KGW crystals, under lasing or nonlasing conditions. Measured thermal lenses are aberration-free, and their focal lengths under lasing action range from 40 to 140 mm for 5 W of absorbed power. When laser action was inhibited the thermal lens dioptric power was increased significantly in most crystals, supplying evidence that nonradiative mechanisms exist. Reduction of thermal effects in a composite YCOB crystal is also investigated, as well as the dependence of thermal lensing on the emission wavelength in YSO. 2002 Elsevier Science B.V. All rights reserved.

Diode-pumped continuous-wave and femtosecond laser operations of a heterocomposite crystal Yb 3+ :SrY 4 (SiO 4 ) 3 O?Y 2 Al 5 O 12

We report cw and femtosecond laser operations under diode pumping of a diffusion-bonding heterocomposite Yb-doped crystal: Yb3+:SrY4(SiO4)3O parallel Y2Al5O12(YAG paralell SYS:Yb). To show the advantages of this heterocomposite crystal over classical Yb:SYS crystal, we first investigate the high-power cw regime. A cw power of 4.3 W is demonstrated. The femtosecond regime is also investigated, and 1-W-average-power, 130-fs pulses at 1070 nm are produced, which represents, to our knowledge, the first demonstration of an Yb-doped heterocomposite mode-locked laser.

Mechanical, thermal and laser properties of Yb:(Sr1−xCax)3Y(BO3)3 (Yb:CaBOYS) for 1 μm laser applications

Abstract Yb:Sr3Y(BO3)3 also known as Yb:BOYS has recently demonstrated very attractive laser properties, but a drawback with this material is its brittleness. It could break into small pieces, even under weak thermal loading. This behavior is attributed to its very large thermal expansion anisotropy: αc/αa∼4. This ratio can be lowered to ∼1.7 by replacing 50% of Sr2+ by Ca2+ in the structure, which strengthen the crystal lattice and allows to reduce the brittleness. However, the thermal properties are affected by the Sr/Ca substitution as the thermal conductivity decreases by around 20 at.% for a 30 at.% calcium containing material. Laser characteristics under diode pumping with Yb3+:(Sr0.7Ca0.3)3Y(BO3)3 crystals (containing 15% Yb) remain comparable to those obtained with Yb:BOYS.

Diode-pumped operation of Yb:GGG laser

Summary form only given. We demonstrated efficient diode-pumped operation of Yb:GGG. 1.85 W of laser power at 1022 nm was obtained, with a small-signal gain of 2.26. Quite similar to YAG as far as spectroscopic and thermal properties are concerned, it might be a reliable competitor of the latter for high power laser systems.

Organic Lasers Resonators

In this chapter we present the main resonators used for organic solid-state lasers, with a special emphasis on those based on thin-films such as planar waveguides or vertical external surface-emitting cavities. The influence of the resonator type on the laser properties (threshold, efficiency slope, output power, beam quality) is reviewed, with a special emphasis on works published after the year 2000.

Organic Materials for Solid-State Lasers

In this chapter we describe organic materials used in laser systems. We define a classification for organic molecules, and give some details about the chemical structure and the optical properties of some of the main families widely used as gain materials or host matrices in organic lasers. The technological processes allowing organic molecule deposition in various forms are then reviewed, as well as the main experimental techniques used to measure crucial parameters such as optical gain.