Sunday, July 5, 2009

SINGLE DYE MOLECULE AS AN OPTICAL TRANSISTOR

During 2nd year of my Ph.D.(2005-06) at JNCASR, I had the privilege of presenting a general seminar on ELECTROMAGNETICALLY INDUCED TRANSPARENCY. One of tricks I came across during the preparation of the talk was to modulate electronic transition of an atom or a molecule by intelligently choosing a pump and a probe laser beam. Based on the same principle, a letter in NATURE reports ‘A SINGLE MOLECULE OPTICAL TRANSISTOR

Following are the highlights of the paper for a science enthusiast:

1. Just as electrons in an electronic device can be modulated by transistor, photons radiated from a single dye molecule can be modulated (i.e., amplified or attenuated) using laser beams, which makes the whole system an optical transistor.

2. A pump laser beam (a pulsed laser) acts as gate and a probe beam (continuous wave laser) acts as the source.

3. By varying the power of the gate laser, the absorption and emission of light from a dye molecule can be modulated.

Following are some of the advantages of an optical transistor:

1. Photons are better candidates for long distance communication.

2. Unlike electronic signals, photonic signals do not perturb each other.

3. Coherence of photons can be maintained at a relatively higher temperature than electrons, which make them better candidates for quantum computation.

This recent report is indeed a breakthrough, and it is worth prusuing further research on the same lines. Ultimate goal can be an OPTICAL COMPUTER……

2 comments:

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  2. Interesting article...optical computer is exciting stuff! I have been looking out for a few ideas in this field..like the Dye based optical transistor...If we can integrate some of theses prototypes and integrate them as in todays Integrated circuits...It would be interesting to see how they perform!
    I was also interested in looking for things that would carry the light signals from one end of the optical circuitry to the other with all the optoelectronic manipulations in the middle. The dimensions of the tracks to carry the photonic signals surely is challenging.But dont you think the resolution and diffraction limit is a problem with photonic signals when clubbed with optoelectronic circuitry?

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