Surface plasmon polaritons on thin metal films are a well studied phenomena when excited using prism coupled geometries such as the Kretschmann attenuated total reflection configuration. Here we describe a novel interference pattern in the conically scattered light emanating from such a configuration when illuminated by a focused beam. We observe conditions indicating only self-interference of ...

We describe a highly sensitive and stable quantum-cascade-laser-based attenuated total reflection (ATR) terahertz sensor for the detection of very low concentration solutions, using dual-modulation differential approach ATR geometry. This offers high dynamic range long-term stability 40 dB, which extends potential radiation analysis liquid biological samples. The performance is illustrated by m...