4.5 mW of power in a single spatial mode has been obtained from a vertical cavity surface emitting laser (VCSEL) in an external cavity setup, using a graded index (GRIN) lens with a spatial filtering high reflecting aperture deposited on its endface. The spatial filter on the GRIN lens endface forces a larger single transverse mode in the VCSEL than is obtained without it. A brightness of5.1×105 W/cm2str is demonstrated, which is 91&percent; of the maximum achievable. ©1997 American Institute of Physics.