Near-field infrared imaging with a microfabricated solid immersion lens

We report imaging in the infrared with a microfabricated solid immersion le ns. The integrated 15-mu m-diameter lens and cantilever are fabricated from single-crystal silicon and scanned in contact with a sample to obtain an i mage. We demonstrate a focused spot size of lambda/5 and an effective numer ical aperture of 2.5 with lambda=9.3 mu m light. The total power transmitte d through the lens is a factor of 10(3) greater than through a metal apertu re giving the same spatial resolution. Two 1.0 mu m holes in a metal film s eparated by 3.0 mu m are imaged with the solid immersion lens in transmissi on and shown to be resolved. (C) 2000 American Institute of Physics. [S0003 -6951(00)05239-6].