Abstract
The finite angular spectral width of a 2D resonant grating mirror is adjusted to select the fundamental transverse mode of a laser and to filter out higher order modes. The selection principle is explained phenomenologically on a simplified 1D model. The 2D design is made so as to sustain the large field concentration in the grating slab-waveguide mirror, and the technology permitting to obtain the resonant reflection within the gain bandwidth of two types of laser is described. The blank experimental measurements by means of a white light supercontinuum are shown to match the targeted specifications on the resonance spectral position and angular width.
Highlights
After having demonstrated the polarization [1] and wavelength [2] selectivity properties of resonant reflection from a waveguide grating for the control of laser emission, the authors of the present paper are completing here the exploration and exploitation of these waveguide grating properties with the last, and still to be demonstrated, optical function of transverse mode selection
Resonant reflection from a waveguide grating mirror exhibits this specific and highly useful characteristics that it represents a filter of the transverse modes in the angular spectrum, permitting the angularly selective mirror to be placed close to the active medium without limiting the emitting laser area with the most important consequence that the laser power can be extracted from a wide pumped area while achieving higher order transverse mode filtering out
The present paper reports on the design (Section 2), the waveguide grating technology and the blank characterization measurements of two different mirror structures (Section 3): one for an erbium-doped microchip laser emitting in the C-band, and one for a high power Yb:YAG disk laser at 1030 nm wavelength (“blank characterization” of the mirrors stands here for the measurement outside the laser resonator of their selectivity properties)
Summary
After having demonstrated the polarization [1] and wavelength (or longitudinal mode) [2] selectivity properties of resonant reflection from a waveguide grating for the control of laser emission, the authors of the present paper are completing here the exploration and exploitation of these waveguide grating properties with the last, and still to be demonstrated, optical function of transverse mode selection. Resonant reflection from a waveguide grating mirror exhibits this specific and highly useful characteristics that it represents a filter of the transverse modes in the angular spectrum, permitting the angularly selective mirror to be placed close to the active medium without limiting the emitting laser area with the most important consequence that the laser power can be extracted from a wide pumped area while achieving higher order transverse mode filtering out. The present paper reports on the design (Section 2), the waveguide grating technology and the blank characterization measurements of two different mirror structures (Section 3): one for an erbium-doped microchip laser emitting in the C-band, and one for a high power Yb:YAG disk laser at 1030 nm wavelength (“blank characterization” of the mirrors stands here for the measurement outside the laser resonator of their selectivity properties) These mirror structures represent two examples where the optical function of transverse mode selection can be beneficially implemented
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