Title

Diffractive optical elements for pitchfork beam shaping

Authors

Authors

C. Zhang; N. R. Quick;A. Kar

Abbreviated Journal Title

Opt. Eng.

Keywords

laser beam shaping; diffractive optics; lens design; pitchfork beam; laser microvia drilling; FOCAL-PLANE IRRADIANCE; PHASE PLATES; ALGORITHM; DESIGN; PROFILE; Optics

Abstract

A set of laser beam shaping optics is designed by an iterative method using an adaptive additive algorithm to transform a Gaussian beam into a pitchfork beam. Two diffractive optical elements are designed based on Fresnel diffraction to reduce the amount of energy in the first-order diffraction ring and to increase the depth of focus for the optical system. These two beam properties are found to depend on the diameter of the desired beam and the Airy disk diameter. If the diameter of the desired beam is large, then the optical system yields better results in achieving the above-mentioned two beam properties. The performance of the diffractive optical elements is compared to a previous laser beam shaping system designed by the ray-tracing technique. A pinhole scanning power meter is used to measure the laser irradiance profile at the focal plane to verify the existence of the pitchfork beam. The irradiance profile measurement shows that diffractive optical elements allow better control for reducing the amount of energy in the diffraction side lobes. (C) 2009 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3183919]

Journal Title

Optical Engineering

Volume

48

Issue/Number

7

Publication Date

1-1-2009

Document Type

Article

Language

English

First Page

9

WOS Identifier

WOS:000268489400039

ISSN

0091-3286

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