New Optomechanical Crystal Allows Confinement of Light and Sound

PBH writes "Physicists and engineers at the California Institute of Technology (Caltech) have developed a nanoscale crystal that traps both light and sound. The interaction of light quanta (photons) and sound quanta (phomons) are so strong that they produce significant mechanical vibrations. 'Indeed, Painter points out, the interactions between sound and light in this device—dubbed an optomechanical crystal—can result in mechanical vibrations with frequencies as high as tens of gigahertz, or 10 billion cycles per second. Being able to achieve such frequencies, he explains, gives these devices the ability to send large amounts of information, and opens up a wide array of potential applications—everything from lightwave communication systems to biosensors capable of detecting (or weighing) a single macromolecule. It could also, Painter says, be used as a research tool by scientists studying nanomechanics. "These structures would give a mass sensitivity that would rival conventional nanoelectromechanical systems because light in these structures is more sensitive to motion than a conventional electrical system is."'"

Comments

Phonon, not phomon

[pac109]

http://en.wikipedia.org/wiki/Phonon

Re:Phonon, not phomon

[Luyseyal]

I think this is better than the wikipedia intro:
http://hyperphysics.phy-astr.gsu.edu/hbase/Solids/phonon.html

The vibrational energies of molecules, e.g., a diatomic molecule, are quantized and treated as quantum harmonic oscillators. Quantum harmonic oscillators have equally spaced energy levels with separation DE = hu. So the oscillators can accept or lose energy only in discrete units of energy hu.

The evidence on the behavior of vibrational energy in periodic solids is that the collective vibrational modes can accept energy only in discrete amounts, and these quanta of energy have been labeled "phonons". Like the photons of electromagnetic energy, they obey Bose-Einstein statistics.

-l

Not a fundamentally new idea

[eh2o]

Obviously the nano scale fabrication seen here is an innovation, but the idea of acoustic-optical interactions is not a fundamentally new one. For example an acousto-optical tunable filter uses piezo-actuation (sound) to setup standing waves in a crystal that modulates a band-pass filter. http://en.wikipedia.org/wiki/Acousto-optics

Re:Add an electret or piezoelectric bit...

[Interoperable]

Well the confined optical mode is 200THz so an RF EM mode wouldn't be confined and therefore wouldn't overlap effectively with the vibronic modes in the nano-structure. I also really doubt that inducing vibrations in the nano-structure would generate an optical (or other EM) field. It's probably a one way coupling given that it's driven by photon pressure and not any net charge in the nano-beam.

Re:help me with this

[gtbritishskull]

You seem to have been asleep for the past 50 years, so I will let you in on a little secret. Transistors were big too when they were first invented. They got smaller as there was more investment and research into them. I would not expect the first form of something in the lab to be at the pinnacle of its efficiency.