Two-photon photocurrent imaging of vertical cavity surface emitting lasers

We show that two-photon photocurrent imaging can be used to nondestructively study vertical cavity surface emitting lasers on a microscopic level. In particular, we study the aperture isolation created by shallow ion implantation. The combination of two-photon backside imaging and a probe station is ideal for internal and full wafer characterization. The required peak and average power levels for testing can be easily satisfied by available compact ultrafast laser sources, making the technique practical and user friendly.