Iterative 3D modeling of thermal effects in end-pumped continuous-wave HO3+^{3+}:YAG lasers

We present a highly accurate model for end-pumped continuous-wave Ho$^{3+}$:YAG laser resonators, based on a vectorial beam propagation method (BPM) algorithm. Thermal effects in the laser crystal like thermal lensing and stress birefringence are taken into consideration. The implementation of these effects is based on an iterative method, which updates the temperature and displacement in the crystal at specific roundtrip intervals. An experimental Ho$^{3+}$:YAG resonator cavity in continuous wave operation is used to validate the model. At higher pump powers, the resonator reaches its stability limit and shows beam distortions, which is well replicated with the presented model

Limitations of homogeneous and segmented single-crystal compact TEM00_{00}-mode Ho3+^{3+}:YAG laser resonators

We present investigations on output power limitations of near-diffraction-limited compact Ho$^{3+}$:YAG laser resonators employing a homogeneous or segmented laser crystal. An approach for designing a segmented crystal is presented. Maximum output powers of 57.6W and 51.9W are reached with the homogeneous and segmented crystal, respectively, resulting in pulse energies of 1.14mJ and 1.04mJ at a repetition rate of 50kHz in Q-switched operation. Interferometric experiments are conducted to derive the radial temperature profile for both crystals. Simulations based on a split-step beam propagation method are used to model the longitudinal temperature gradient in both crystals

High power Q-switched thulium doped fibre laser using carbon nanotube polymer composite saturable absorber

We have proposed and demonstrated a Q-switched Thulium doped bre laser (TDFL) with a ‘Yin-Yang’ all- bre cavity scheme based on a combination of nonlinear optical loop mirror (NOLM) and nonlinear ampli ed loop mirror (NALM). Unidirectional lasing operation has been achieved without any intracavity isolator. By using a carbon nanotube polymer composite based saturable absorber (SA), we demonstrated the laser output power of ~197 mW and pulse energy of 1.7 μJ. To the best of our knowledge, this is the highest output power from a nanotube polymer composite SA based Q-switched Thulium doped bre laser

Imagerie de fluorescence induite par laser (application à la reconnaissance des groupes de macroalgues)

BREST-BU Droit-Sciences-Sports (290192103) / SudocSudocFranceF