Low temperature near-field scanning optical microscopy on infrared and terahertz photonic-crystal quantum cascade lasers
Résumé
We report the development of a scattering-type near-field scanning optical microscope sNSOM which operates at temperatures down to 100 K with a scanning range of up to 400 microns. We have used this sNSOM to map the electromagnetic near-field on mid-IR and terahertz THz surface emitting quantum cascade lasers with photonic-crystal resonators. Mid-IR devices operate at lambda =7.5 microns ( 40 THz) while THz devices operate at lambda =110 microns( 2.7 THz ). The near-field images--in agreement with numerical calculations--demonstrate an instrument resolution of 100's nm.