1. High power VBG Yb-fiber laser
Slope eff. ~75 %
Δλ = 0.4 nm
M2~5.5
Yb-fiber Core:  30 m, NA 0.056
D-shaped cladding :  400 m, NA 0.49
Fiber length : ~8 m (abs. ~2 dB/m at 975 nm)
Launch efficiency : ~90 %
VBG 1.5mm 3mm 5mm
Δλ = 0.22 nm, λcentre = nm, R= 99 %
AR coated
surface normal polished ~2o to the grating vector
P. Jelger, P. Wang, J. K. Sahu, F. Laurell, and W. A. Clarkson, Opt. Expr. 16, 9507 (2008)

2. Transversally chirped VBG Yb laser
> 100 W output
> 78 % slope efficiency
Tunable from nm
<0.5 % power fluctuation over tuning range
Narrowband signal < 50 pm
Temporal stability <0.2 % rms
M2 = 1.2
Single-polarization >18 dB PER
Tcvbg – design wavelength of the grating is chirped such that lateral translation will tune the laser wavelength
Low core NA --> easy to operate the fiber in a single mode  since higher order modes are strongly suppressed by coiling  particularly important for self-pulsing suppression
Expected perfomance: calculate the laser power at maximum launched pump power using a spectrally resolved rate equation model
Using available yb absorption and emission cross sections…
Take a look at the scale of the color bar on the right hand side…
1st Obviously  high gain laser medium
2nd due to the rather constant emission cross section of Yb in that region…
SBS threshold approx. 5 kW

3. Tunable, high-power, 2 wavelength Yb laser
Dual-line lasing 78 W
wavelength separation
THz,
Power fluctuation<1 %.
Results for the SHG generation

4. Kerr-Lens ML Ti:sapphire laser
Ultra-fast lasers
Kerr-Lens ML Ti:sapphire laser
D.E. Spence, P.K. Kean, and W. Sibbet Opt. Lett. 16, 42 (1991)
M. Piché, Opt. Commun. 86, 156 (1991)
Patent for the Aperture (Coherent)

5. The Frequency Comb T
 = phase offset between carrier wave and wave envelope
fm = mfrep + foffset
frep= 1/T
foffset = ( /2) frep
Therefore if
 = 0  foffset= 0 
fm = mfrep
The idea has revolutionized the art of frequency measurements
Theodor W. Hänsch e John L. Hall, Nobel Prize for Physics (2005)

6. High Peak Intensities Lasers
oscillator 
stretcher
up to 105
amplifier
 10-3 – 10-5
compressor
Chirped Pulse Amplification (CPA)
D. Strickland and G. Mourou (1985)
 Ti:Al2O3 : mJ; f = 1-10 kHz
 TTT [Terawatt Table Top] Lasers : 100 TW (5 J, 50 fs)
 Petawatt-class Lasers (1,5 PW, i.e. 580 J and 460 fs)

7. Historical Evolution of Pulse Duration
From Femtoseconds to Attoseconds
4 fs
80 as: E. Goulielmakis et. al., Science 320, 1614 (2008)

9. Everything...

10. In Science Laser cooling Na-atom molasses
6 laser beams with frequency slightly
shorter than the transition frequency.
Reduced the energy of a cloud of atoms
to form an optical molasses.
Temperatures down to micro-Kelvin.
Nobel prize in 1997 for Chu,
Cohen-Tannoudji and Phillips

11. The world's largest and highest-energy laser
the National Ignition Facility at Lawrence Livermore
In the NIF experiments 192 giant laser beams are focused on a cm-sized target filled with hydrogen fuel.
NIF's goal is to fuse the hydrogen atoms' nuclei and produce net energy gain (Eout = 100 Ein)
The beams compress the target to 100 billion times the atmosphere to a temperature of 100 million °C

12. Imaging and displays – large, small or 3D

14. References can be found on
Conclusions
Solid-state lasers
efficient
Reliable
tailored
fun
And….
Acknowledgments
Friends and laser family
References can be found on

15. That´s all folks!

16. Hollow fiber dye and Q-dots sources
Scematic layout
Photograph of
Rodamine 6G
filled fiber
Green pumped hollow fibre in wich dye is pumped

17. Functional optical materials and structures
Chemically and photostructured glasses
Domain engineered ferroelectrics
Quantum dots
Silicone elastomers
Microstructured silicon

18. Acknowledgments Laser physics group National and
international colleagues

19. Limitations related to thermal loading
2 mm
FEM simulation
Width of VBG [mm]
Distance into VBG [mm]
Temperature
distribution
1 kW
3 mm
5 mm
Absorption 0.2%/cm
Δ λ ~ 0.5 nm
Chirp reduces reflectivity!
VBG would transmit more power!
Significant problem for low gain lasers
and high circulating powers

20. > 30 W Single Frequency CW VBG OPO
P. Zeil, et al. Optics Express, 22, (2014).