GaSe electro-optic sensors for ultrabroadband detection of multi-THz field transients

Electro-optic detection with unprecedented bandwidth is implemented with GaSe sensors utilizing phase matching. We directly record transform-limited 28-fs pulses containing spectral components beyond 120 THz (/spl lambda/=2.5 /spl mu/m). Using thicker crystals, the continuous tunability of the detector response is demonstrated between 14 THz and 31 THz.