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(21) Propagation-invariant fractal beams
¡¡¡¡¡¡Technical Digest of Fifth Finland-Japan Joint Symposium on Optics in Engineering, pp.G3, 2003-8
It is known that propagation-invariant or nondiffracting waves can be generated using several types of optical systems such as one involving an annular aperture of small width illuminated by a coherent plane wave. In this case, a Bessel beam of order zero, the most fundamental propagation-invariant beam, appears in the region behind a lens placed in the focal distance from the annular aperture. More complicated propagation-invariant waves or beams are generated by modulating the transmittance of the annular aperture. It is shown in this report that propagation-invariant beams with regular fractal property can be produced by employing fractal functions as the modulation function.
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