Terahertz surface plasmon resonance microscopy based on ghost imaging with pseudo-thermal speckle light

摘要

Surface plasmon resonance (SPR) microscopy is one of the most sensitive optical label-free methods of metal/semiconductor surface microscopy. Nevertheless, it does not have sufficiently high lateral resolution. This is due to the fact that surface plasmon polaritons excited by terahertz (THz) radiation propagate from their excitation spot over macro distances (about $sim 100 lambda$), thereby blurring the observed area, by analogy with a scattering medium. To eliminate this disadvantage, we propose to adapt the single-pixel imaging technique known as ghost imaging (GI), which is notable for its tolerance to environmental aberrations between an object and a camera. To implement the classical GI for THz SPR microscopy we propose to use spatially modulate light by speckle patterns arising from the reflection of coherent THz radiation (generated by a free electron laser) from a rough metal surface.