Paper
Fractional Axicon as a New Type of Diffractive Optical Element with Conical Focal Region
- Authors:
- Andrey V. Ustinov; Sergey G. Volotovsky; Svetlana N. Khonina
- Abstract
- We theoretically investigated the transverse parameters and the depth of the focal region formed by a lensacon (a tandem of a lens and an axicon). In this case the focal spot size becomes variable and it can be smaller than when optical elements are used separately. The concept of a new phase diffractive optical element (DOE) – fractional axicon – is introduced. It has a fractional dependence on the radial coordinate. Depending on the value of the power the fractional axicon allows to form either a decreasing scale or an increasing scale Bessel beams with a corresponding field depth extension. In the former case the fractional axicon is similar to the lensacon and in the latter case it is similar to the logarithmic axicon but there is no singularity in the centre. Thus, the offered element expands a set of the optical elements forming “light strings” actively used in metrology.
- Keywords
- Linear Axicon; Lensacon; Fractional Axicon; Focal Spot Size; Field Depth
- StartPage
- 132
- EndPage
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