Los Alamos National
Laboratory has produced the first known material capable of single-photon
emission at room temperature and at telecommunications wavelengths. These
carbon nanotube quantum light emitters may be important for optically-based
quantum information processing and information security, while also being of
significant interest for ultrasensitive sensing, metrology and imaging needs
and as photon sources for fundamental advances in quantum optics studies.
Read more at: https://phys.org/news/2017-07-single-photon-emitter-quantum-info-processing.html#jCp
Read more at: https://phys.org/news/2017-07-single-photon-emitter-quantum-info-processing.html#jCp
Why century 21?
In optical communication,
critical information ranging from a credit card number to national security
data is transmitted in streams of laser pulses. However, the information
transmitted in this manner can be stolen by splitting out a few photons (the
quantum of light) of the laser pulse. This type of eavesdropping could be
prevented by encoding bits of information on quantum mechanical states (e.g.
polarization state) of single photons. The ability to generate single photons
on demand holds the key to realization of such a communication scheme
Read more at: https://phys.org/news/2015-09-nanotubes-path-quantum-technologies.html#jCp
Why the prediction?
Read more at: https://phys.org/news/2015-09-nanotubes-path-quantum-technologies.html#jCp
Why the prediction?
Ideally, a single photon
emitter will provide both room-temperature operation and emission at telecom
wavelengths, but this has remained an elusive goal. Up to now, materials that
could act as single photon emitters in these wavelengths had to be cooled to
liquid helium temperatures, rendering them much less useful for ultimate
applications or scientific purposes
How done?
How done?
Force the nanotube to emit
light from a single point along a nanotube, only at a defect site. The key was
to limit defect levels to one per tube. One tube, one defect, one photon. . . .
By emitting light only one photon at a time, one can then control the photons'
quantum properties for storage, manipulation and transmission of information.
Wavelength controlled by carrying tube diameter, you can make different
frequency elements. Change it dynamically – tunable room temperature single
photon emitter is next step. Also doable by dynamic pinching of many tubes in
parallel. Hence the prediction.
How built?
This degree of control using diazonium-based chemistry, a process they
used to bind an organic molecule to the nanotube's surface to serve as the defect. The diazonium reaction chemistry allowed a
controllable introduction of benzene-based defects with reduced sensitivity to
natural fluctuations in the surrounding environment. Importantly, the
versatility of the diazonium chemistry also permitted the researchers to access
the inherent tunability of nanotube emission wavelengths.