OPTICAL ELEMENT FOR VERTICAL EXTERNAL-CAVITY SURFACE-EMITTING LASER

摘要

The present invention relates to an optical element for VEC-SELs or VECSEL arrays. The optical element is formed of a substrate (200) which is transparent at least in a wavelength region of optical radiation. A first interface of the- substrate (200) comprises one or several curved regions forming part of an optical lens or of an array of optical lenses (220) integrated in the substrate (200). The substrate (200) further comprises one or several optical mirrors (210) formed on a second interface of the substrate (200) opposing the first interface or embedded in the substrate (200). The optical mirrors (210) are arranged and designed to back reflect a fraction of optical radiation incident on the first or second interface. The optical mirrors (210) are flat mirrors or curved mirrors having a radius of curvature different from the radius of curvature of the curved region (220). The optical element allows the fabrication of a VECSEL or VECSEL array having a high brightness without the requirement of additional adjustments during fabrication. The VECSEL are arranged at a distance (L) to the optical mirrors (210) and this equals the length of the external cavity. The ROC of the optical lens may be chosen to ROC=L/2 and for the optical mirror ROC>L. The cavity length may be adjusted by a monolithic spacer (120)