NANOPHYSICS

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Any condensed matter systems whose at least one (out of three) dimension is of the order of nanometer can be considered as Nano scale system.

Nano science and nanotechnology are all about relating and exploiting phenomena for materials having one, two or three dimensions reduced to the Nano scale. Their evolution may be traced to three exciting happenings that took place in a short span from the early to mid-1980s with the award of Nobel prizes to each of them. These were:

  1. the discovery quantum Hall effect in a two-dimensional electron gas.
  2. the invention of scanning tunneling microscopy (STM)
  3. the discovery of fullerene as the new form of carbon.

The latter two, within a few years, further led to the remarkable invention of the atomic force microscope (AFM) and, in the early 1990s the extraordinary discovery of carbon nanotubes (CNT), which soon provided the launch pad for the present-day nanotechnology. The STM and AFM have emerged as the most powerful tools to examine, control and manipulate matter at the atomic, molecular and macromolecular scales and these functionalities constitute the mainstay of nanotechnology. Interestingly, this exciting possibility of Nano level tailoring of materials was envisioned way back in 1959 by Richard Feynman in his lecture, “There’s plenty of room at the bottom.”

Why are Nanostructures Interesting for Basic Research?

  • Enhanced role of surface atoms with their unpaired spins and uncompensated bonds
  • Reduced dimensionality at the Nano scale = strongly modified Density of States, enhanced Coulomb interaction …
  • Quantum confinement effects = discrete energy levels

‘Accelerator on a chip’ demonstrated

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In an advance that could dramatically shrink particle accelerators for science and medicine, researchers used a laser to accelerate electrons at a rate 10 times higher than conventional technology in a nanostructured glass chip smaller than a grain of rice.

It could also help enable compact accelerators and X-ray devices for security scanning, medical therapy and imaging, and research in biology and materials science.
Because it employs commercial lasers and low-cost, mass-production techniques, the researchers believe it will set the stage for new generations of “tabletop” accelerators.
Today’s accelerators use microwaves to boost the energy of electrons. Researchers have been looking for more economical alternatives, and this new technique, which uses ultra fast lasers to drive the accelerator, is a leading candidate.

In the accelerator-on-a-chip experiments, electrons are first accelerated to near light-speed in a conventional accelerator. Then they are focused into a tiny, half-micron-high channel within a fused silica glass chip just half a millimeter long. The channel had been patterned with precisely spaced Nano scale ridges. Infrared laser light shining on the pattern generates electrical fields that interact with the electrons in the channel to boost their energy.