Optical image processing by an atomic vapour

Ivan Biaggio*, Jouni P. Partanen, B. Ai, R. J. Knize, Robert W. Hellwarth

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

17 Citations (Scopus)


ATOMIC vapours can exhibit large optical nonlinearities1. When laser light is tuned in resonance with an atomic transition, the absorption cross-section of the atom can become very large, typically seven orders of magnitude larger than the cross-sectional area of its electron cloud 2. Because of these strong nonlinearities different laser beams can interact with one another in an atomic vapour, even at intensities as low as a few milliwatts per cm2. This raises the question1 of whether atomic vapours can be used as nonlinear optical elements for parallel optical image processing. A well-known example of an all-optical image processor is the optical correlator: laser beams with imprinted images interact in a nonlinear medium to produce a signal beam, the intensity distribution of which is related to the correlation integral of (and hence the degree of similarity between) the input images. Here we demonstrate the use of a caesium-atom vapour as the active medium in such an optical correlator. We show that this system compares favourably with others currently in use particularly with regard to its power requirements.

Original languageEnglish
Pages (from-to)318-320
Number of pages3
Issue number6495
Publication statusPublished - 22 Sep 1994
MoE publication typeA1 Journal article-refereed

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