DETAILS OF THE ACHIEVEMENT
| Holographic Gaussian to flat-top beam shaping | ||
| Prof. Miroslav Miler, DSc.; Ivo Aubrecht, Ph.D.; Jan Pala, Ph.D. | ||
| Year: 2003 | ||
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Spatially uniform illumination or irradiation of particular surface
areas by a coherent optical beam is required in many different
information processing and printout technological processes, in
industrial and medical applications, etc. The profile of a standard
coherent beam is Gaussian, with a rounded top. For more uniform
illumination the beam must be expanded and only its central part can
be utilised. The surface density of illumination is considerably
reduced, however. Another possibility is to re-shape the beam profile
so as to get a more flat top. Formation of such beams represents
presently a hot research topic in many research laboratories in the
world. A viable way to this goal consists in the implementation of a
nonuniform holographic optical element, the surface profile of its
diffraction efficiency acts to suppress the central part and to boost
the peripheral parts of the incident beam. Our research in this
direction has resulted in the development of a holographic filter in
the form of a matrix of non-uniform grating structures. A suitable
near-optimum element of this matrix that possesses the required beam
uniformity can then be selected experimentally, without any
preliminary measurements and/or calculations.
Left – the matrix of realised holographic filters. Right – the profile of a flattened beam obtained by the transition of a Gaussian beam by a filter in a suitably chosen matrix element. |
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