A detector system for performing at least one of transmitting and
receiving electromagnetic radiation at a low-terahertz frequency. The
detection of electromagnetic radiation at low-terahertz frequencies can
be useful in the detection of various chemicals. Preferably a detector
includes a microresonant structure that is caused to resonate by
electromagnetic radiation at a low-terahertz frequency. The resonance is
detected by detecting an altered path of a charged particle beam.