Speaker
Level for award<br> (Hons, MSc, <br> PhD)?
No
Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?
Yes
Main supervisor (name and email)<br>and his / her institution
NO
Apply to be<br> consider for a student <br> award (Yes / No)?
No
Abstract content <br> (Max 300 words)
1.9 µm Tm:YLF slab lasers are used to pump high energy Ho:YLF slab amplifiers [1] as well as for applications in medicine and defense. We have previously demonstrated high average powers (~200 W) from such a system at ~1.9 µm. However, efficient pumping of Ho:YLF requires that the Tm:YLF output wavelength reasonably well match one of Ho:YLF’s two strong absorption peaks at either 1890 nm or 1940 nm. This is usually accomplished by polarization and output-coupler selection using threshold calculations. Volume Bragg Grating (VBG) mirrors offer a more precise and sure way to select a specific wavelength. A VBG mirror has a periodic variation of the refractive index and is transparent at most wavelengths. It has a high reflectivity at a certain wavelength which fulfills the Bragg condition (in this case 1890 nm). We used a VBG as a back-reflector in a Tm:YLF slab laser. The slab crystal was pumped with a 300 W, 792 nm diode stack using a pump reproducing scheme. It delivered over 80 W of output power at 1890 nm and had a good beam quality compared to other slab laser systems. We also report on initial results of this system pumping a 60 mm Ho:YLF crystal laser. The results indicate that the technology shows great promise for wavelength selection and stabilization of other crystal and fibre laser systems.
