Using electric field induced second harmonic generation to probe electric fields in semiconductor devices

We observe the voltage dependent electric field induced second harmonic generation from the active region of a GaN UV light emitting diode (LED) (Nichia). By probing below one half the bandgap using a Ti:sapphire laser, we can still take advantage of near-resonance enhancement at the second harmonic while reducing absorption (invasiveness) and allowing penetration into the device. Ultimately, we hope to use this technique to probe silicon-based integrated circuits using infrared light.