Holographic formation of a diode laser nondiffracting beam.

We report for the first time, to our knowledge, the characteristics of a so-called nondiffracting beam produced by illumination of a binary-phase reflective holographic optical element with light from a diode laser. The Bessel beam has an intensity profile whose pattern changes little over distances of order 1 m and has a 1/e amplitude radius for the central lobe of ∼100 µm. This beam may have application for alignment of integrated optic elements in which unguided diffraction-free beams are used to align glass-slab elements containing interconnection holograms to a computer board. The aligning Bessel beam would be produced on reflection from a hologram on the glass-substrate interconnecting element. A single hologram may be used for different substrates having different lengths and functionality because of the large depth of field of the Bessel beam.