Scientists at the University of Tokyo
and the Japan Science and Technology Corporation have been able to
detect single photons in the terahertz region of the electromagnetic
spectrum for the first time. Previously, such photons, with
energies around 4 millielectronvolts, could not be seen singly.
Terahertz radiation, essentially in the far-infrared, is a potentially
important telecommunications carrier. Not only detection but
microscopy at ultra-low terahertz light levels can be performed.
scanning a quantum-dot probe (highly sensitive to terahertz light) across
the face of a sample, the sample can be imaged with a
spatial resolution of 50 microns; the radiation itself has a
wavelength of 132 microns. This is even more remarkable when you
consider that the power emitted from the surface being imaged is at
the level of 10-19 watts (0.1 attowatt).
microscopy glimpses a few electrons at a time oscillating at terahertz
frequencies in semiconductor devices at high magnetic fields.
According to Kenji Ikushima (email@example.com), the
extraordinarily high-sensitivity of the photon counting approach
will soon facilitate the study of a molecule shaking, rattling and
rolling at terahertz rates. Photon-counting microscopy in this spectral
range will facilitate the study of a few molecules at a time
oscillating at terahertz frequencies in semiconductor devices at high
Ikushima et al., Applied Physics Letters, 10
The Komiyama Lab at the University