Broad aperture semiconductor lasers usually suffer from low spatial quality of the emitted beams. Due to the highly compact character of such lasers the use of a conventional intra-cavity spatial filters is problematic. We demonstrate that extremely compact Photonic Crystal spatial filters, incorporated into the laser resonator, can improve the beam spatial quality, and correspondingly, increase the brightness of the emitted radiation. We report the decrease of the M 2 from 47 down to 28 due to Photonic Crystal spatial intra-cavity filtering, and the increase of the brightness by a factor of 1.5, giving a proof of principle of intra-cavity Photonic Crystal spatial filtering in broad area semiconductor lasers.
In this work, we report an experimental and numerical study of the intracavity spatial filtering in edge-emitting lasers using a chirped photonic crystal (PhC) as the filtering element in the near-field domain. We provide a comprehensive analysis of the near-field PhC filtering scheme and compare it to conventional spatial filtering using a variable width slit in the far-field domain. Using a two-dimensional chirped PhC as a spatial filter, we experimentally demonstrate a brightness enhancement by a factor of 1.3, considering an edge-emitting laser with a 1.5 mm cavity length, consistent with a numerical prediction of brightness enhanced by a factor of 1.7. The experimental results are theoretically confirmed by numerical integration of a spatio-temporal model of the edge-emitting laser. Furthermore, numerical results show that brightness can be further increased over a factor of 2, applying optimized spatial-filtering elements at both the front and rear facets of the lasers.
We developed a 1kW cw fiber-coupled diode laser at 9XX nm by employing Lyot-filtered optical reinjection from an external cavity. This technique is insensitive to the thermal drift of the laser diodes. The FWHM spectral width at 1 kW output power is only around 7 nm.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.