Starship Asterisk*

While the optical laser celebrated its 50th anniversary earlier this year, some scientists have been working on a new type of coherent beam amplifier for sound rather than light. Scientists theorize that phonons, which are the smallest discrete unit of vibrational energy, can be amplified by a phonon laser to generate a highly coherent beam of sound (particularly, high-frequency ultrasound), similar to how an optical laser generates a highly coherent beam of light. However, phonon laser research is still a relatively new area. In a new study, scientists have for the first time demonstrated the possibility that phonons can be collectively excited in an ultra-cold atomic gas in a way that is similar to how an optical laser excites photons, prompting the scientists to call the proposed device a "phaser."

The first theoretical phonon laser was proposed one year ago, in 2009, by a team of scientists (Kerry Vahala, et al.) from the Max Planck Insitute and Caltech. In that study, the scientists outlined for the first time how a single magnesium ion can be cooled to a temperature of about 1 milli-Kelvin in an electromagnetic trap, and be used to create a single-ion phonon laser. However, the single-ion phonon laser works somewhat differently than an optical laser, since the phonon frequency is determined by the single-atom oscillation frequency rather than corresponding to a collective oscillation.

In the new study, scientists J. T. Mendonca from the Instituto Superior Tecnico (IST) in Lisbon, Portugal, and colleagues from the IST and Umea University in Umea, Sweden, have extended the concept of the single-ion phonon laser to the case of a large ensemble of atoms. In doing so, they have shown that an ultra-cold atomic gas can enable collective phonon excitations. In contrast with the single-ion case, here the phonon frequency is determined by the internal oscillations of the atoms in the gas, similar to how the photon frequency in a laser is determined by internal vibrations of the optical cavity.

• Europhysics Letters 91 33001 (27 Aug 2010) DOI: 10.1209/0295-5075/91/33001

beyond wrote:Neufer, that's not bad at all. Get a video of Henry Kissinger talking, if you want to see what a low monotonous voice can really do

http://www.technovelgy.com/ct/Science-Fiction-News.asp?NewsNum=2358 wrote:

Star Trek Klingon 'sonic disruptors'

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<<The Saser, new type of acoustic laser-like device, has been produced by Scientists at The University of Nottingham, in collaboration with colleagues in the Ukraine. A Saser produces an intense beam of uniform sound waves on a nano scale. The Saser produces a sonic beam of ‘phonons’ which travels, not through an optical cavity like a laser, but through a tiny manmade structure called a ‘superlattice’. This is made out of around 50 super-thin sheets of two alternating semiconductor materials, Gallium Arsenide and Aluminium Arsenide, each layer just a few atoms thick. When stimulated by a power source (a light beam), the phonons multiply, bouncing back and forth between the layers of the lattice, until they escape out of the structure in the form of an ultra-high frequency phonon beam.

The Saser is the first device to produce sound waves in the terahertz frequency range; its coherent acoustic waves have nanometer wavelengths. A Saser could be used to look for defects in nanometer-scale objects like microelectronic circuits. Professor Anthony Kent from the University’s School of Physics and Astronomy, states: “While our work on sasers is driven mostly by pure scientific curiosity, we feel that the technology has the potential to transform the area of acoustics, much as the laser has transformed optics in the 50 years since its invention.”>>

http://en.wikipedia.org/wiki/Sound_Amplification_by_Stimulated_Emission_of_Radiation wrote:

SASER creates standing waves between tiny drums.
ANDREW LAMBERT PHOTOGRAPHY/SCIENCE PHOTO LIBRARY
http://www.nature.com/news/2010/100226/ ... 10.92.html

<<Sound Amplification by Stimulated Emission of Radiation : A SASER is the acoustic analogue of the laser. It is capable of producing highly coherent, concentrated beams of ultrasound, using methods very similar to those employed in the laser. First experimentally demonstrated in the Gigahertz range in 2009, the SASER is being developed at the University of Nottingham, the Lashkarev Institute of Semiconductor Physics, and Caltech. The University of Nottingham device operates at about 440 GHz, while the Caltech device operates in the megahertz range. In an interview, a member of the Nottingham group, told physicsworld.com that "the two approaches are complementary and it should be possible to use one device or the other to create coherent phonons at any frequency in the megahertz to terahertz range."

A SASER operates on principles remarkably similar to those of a laser. A stack of thin semiconductor wafers are placed in a lattice within an acoustically reflective chamber. Upon the addition of electrons, short-wavelength (in the terahertz range) phonons are produced. Since the electrons are confined to the quantum wells existing within the lattice, the transmission of their energy depends upon the phonons they generate. As these phonons strike other layers in the lattice, they excite electrons, which produce further phonons, which go on to excite more electrons, and so on. Eventually, a very narrow beam of high-frequency ultrasound exits the device.

A second meaning of SASER is the thermoacoustic laser. This is a half-open pipe with a heat differential across a special porous material inserted in the pipe. Much like a light LASER, a thermoacoustic SASER has a high-Q cavity and uses a gain medium to amplify coherent waves.>>

http://en.wikipedia.org/wiki/Horton_Hears_a_Who! wrote:

Is anyone in there?

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<<On the afternoon of May 15 while splashing in a pool located in the Jungle of Nool, Horton the Elephant hears a small speck of dust talking to him. It turns out the speck of dust is actually a tiny planet, home to a city called Who-ville, inhabited by microscopic-sized inhabitants known as Whos and led by a character known as the mayor. His motto is "a person's a person, no matter how small."

The Whos ask Horton (who, though he cannot see them, is able to hear them quite well, due to his large ears) to protect them from harm, which Horton happily agrees to do, proclaiming throughout the book that "even though you can’t see or hear them at all, a person’s a person, no matter how small". In doing so he is ridiculed and forced into a cage by the other animals in the jungle for believing in something that they are unable to see or hear. His chief tormentors are Vlad Vladikoff, the Wickersham Brothers and the Sour Kangaroo. Horton tells the Whos that, lest they end up being boiled in "Beezelnut Oil", they need to make themselves heard to the other animals. The Whos finally accomplish this by ensuring that all members of their society play their part. In the end it is a "very small shirker named JoJo" who invents a pulsed industrial SASER powerful enough for the jungle to hear the sound, thus reinforcing the moral of the story: "a person’s a person, no matter how small".>>