Light emission from vertical cavity surface emitting lasers (VCSELs) is modeled as directed radiation away from a localized source within the VCSEL optical cavity into an open system as a continuous function of frequency, analogous to antenna radiation, but with field sources provided by spontaneous emission and gain. To allow near‐analytical solution, a quasi‐one‐dimensional system is analyzed. This approach reproduces the familiar threshold condition, mode gain times lifetime equals unity, at the cavity quasimode frequency; however, it also predicts that lasing is not restricted to the quasimode frequency. ©1995 American Institute of Physics.