7.4.2. Generation of a Bessel beam with an axicon.
Using an annular slit is of course not very efficient because most of the incoming (laser) beam is not used. A much more efficient way to generate a Bessel beam is the use of an axicon. With such an element in principle all the incoming light is converted. Although all the light is converted most applications are only interacting with the central lobe of the beam, which only carries a small fraction of the total beam power.
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