[ExI] An advance in Nanotechnology

Brent Allsop brent.allsop at gmail.com
Thu Feb 6 22:29:20 UTC 2020


On Thu, Feb 6, 2020 at 3:27 PM John Clark via extropy-chat <
extropy-chat at lists.extropy.org> wrote:

> Atomic scale resolution has been achieved for several decades with
> Scanning Tunneling Microscopes, they work by moving the tip of a super
> sharp needle and measuring the tunneling current induced by quantum
> fluctuations. The tunneling current is extremely sensitive to the distance
> between the needle and the sample so you get excellent spatial resolution,
> but unfortunately you also get very poor temporal resolution. In the
> January 24 2020 issue of the journal Science Garg and Kern report on a way
> to overcome this problem, they could get angstrom (10^-9 meter) level
> spatial resolution and attosecond (10^-18 second) temporal resolution. They
> found that by illuminating the tip of the needle with ultrashort Laser
> pulses they could greatly enhance the induced tunneling current and, unlike
> the normal tunneling current, it would have a well defined phase.
> In addition the editors of Science speculate that "quantum computing
> protocols might harness the coherent tunneling phase"  that Garg and Kern
> have discovered.
> *Abstract*
> *Nanoelectronic devices operating in the quantum regime require coherent
> manipulation and control over electrons at atomic length and time scales.
> We demonstrate coherent control over electrons in a tunnel junction of a
> scanning tunneling microscope by means of precise tuning of the
> carrier-envelope phase of two-cycle long (<6-femtosecond) optical pulses.
> We explore photon and field-driven tunneling, two different regimes of
> interaction of optical pulses with the tunnel junction, and demonstrate a
> transition from one regime to the other. Our results show that it is
> possible to induce, track, and control electronic current at atomic scales
> with subfemtosecond resolution, providing a route to develop petahertz
> coherent nanoelectronics and microscopy.*
> Attosecond coherent manipulation of electrons in tunneling microscopy
> <https://science.sciencemag.org/content/367/6476/411>
> John K Clark
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