1617 nm emission control of an Er:YAG laser by a corrugated single-layer resonant grating mirror

Adrien Aubourg (1, 2) , Martin Rumpel (3) , Julien Didierjean (2) , Nicolas Aubry (2) , Thomas Graf (3) , François Balembois (1) , Patrick Georges (1) , Marwan Abdou Ahmed (3)

1 Laboratoire Charles Fabry / Lasers
2 Fibercryst
3 IFSW - Institut für Strahwerkzeuge

A resonant grating mirror (RGM) that combines a single layer planar waveguide and a subwavelength grating is used to simultaneously control the beam quality, the spectral bandwidth, and the polarization state of an Er:YAG laser. This simple device is compared to classical methods using several intracavity components: an etalon for wavelength selection, a thin film polarizer for polarization selection, and an aperture for spatial filtering. It is demonstrated that the RGM provides the same polarization purity, an enhanced spectral filtering, and a significant improvement of the beam quality. In CW operation, the Er:YAG laser with a RGM emits an output power of 1.4 W at 1617 nm with a M 2 of 1.4. Resonantly diode-pumped Er:YAG laser cavities are studied for their capability to emit a laser beam at wavelengths within the eye-safe region, i.e., at 1617 and 1645 nm, where the atmosphere is mostly transparent. The natural laser emission (i.e., without any wavelength selective component in the cavity) of Er:YAG occurs at 1645 nm since it requires a lower population inversion. However, for applications requiring kilometer range propagation such as telemetry, wind mapping, active imaging , or Lidar in general, laser operation at 1617 nm is more efficient since the atmosphere is free of methane absorption at this wavelength [1]. Moreover, polarized emission is useful for the detection of atmosphere pollutants or materials. Finally, a high beam quality (M 2

Domaines: Optique [physics.optics]

Adrien Aubourg, Martin Rumpel, Julien Didierjean, Nicolas Aubry, Thomas Graf, et al.. 1617 nm emission control of an Er:YAG laser by a corrugated single-layer resonant grating mirror. Optics Letters, 2014, 39 (3), pp.466-469. ⟨10.1364/OL.39.000466⟩. ⟨hal-01304691⟩