Efficient generation of cylindrically polarized beams in an Yb:YAG thin-disk laser enabled by a ring-shaped pumping distribution

Tom Dietrich; Martin Rumpel; Thomas Graf; Marwan Abdou Ahmed

doi:10.1117/12.2230682

27 April 2016 Efficient generation of cylindrically polarized beams in an Yb:YAG thin-disk laser enabled by a ring-shaped pumping distribution

Tom Dietrich, Martin Rumpel, Thomas Graf, Marwan Abdou Ahmed

Author Affiliations +

Proceedings Volume 9893, Laser Sources and Applications III; 98930M (2016) https://doi.org/10.1117/12.2230682
Event: SPIE Photonics Europe, 2016, Brussels, Belgium

Abstract

The efficient generation of a cylindrically (radially or azimuthally) polarized LG₀₁ mode was investigated using a ring-shaped pumping distribution in a high-power Yb:YAG thin-disk laser setup. This was realized by implementing a 300 mm long customized fused silica fiber capillary in the pump beam path of the pumping optics of a thin-disk laser. Furthermore, a grating waveguide mirror based on the leaky-mode coupling mechanism was used as one of the cavity end mirrors to allow sufficient reduction of the reflectivity of the polarization state to be suppressed in the resonator. In order to achieve efficient laser operation, an optimized mode overlap between the ring-shaped pump spot and the excited first order Laguerre-Gaussian doughnut mode is required. This was investigated theoretically by analyzing the intensity distribution generated by different fiber geometries using a commercially raytracing software (Zemax). The output power, polarization state and efficiency of the emitted laser beam were compared to that obtained with a standard flattop pumping distribution. In particular, the thermal behavior of the disk was investigated since the excessive fluorescence caused by the non-saturated excitation in the center of the homogeneously pumped disk leads to a strong heating of the crystal. This considerable heating source is avoided in the case of the ring-shaped pumping and a reduction of the temperature increase on the disk surface of about 21% (at 280 W of pump power) was observed. This should allow higher pump power densities without increasing the risk of damaging the disk or distorting the polarization purity. With a laser efficiency of 41.2% to be as high as in the case of the flattop pumping, a maximum output power of 107 W was measured.

Citation Download Citation

Tom Dietrich, Martin Rumpel, Thomas Graf, and Marwan Abdou Ahmed "Efficient generation of cylindrically polarized beams in an Yb:YAG thin-disk laser enabled by a ring-shaped pumping distribution", Proc. SPIE 9893, Laser Sources and Applications III, 98930M (27 April 2016); https://doi.org/10.1117/12.2230682

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available