Beam homogenizers based on chirped microlens arrays

Wippermann, Frank; Zeitner, U. D.; Dannberg, Peter; Bräuer, Andreas; Sinzinger, Stefan

doi:10.1364/oe.15.006218

Cited by 76 publications

(25 citation statements)

References 7 publications

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“…The goniophotometer measurements with a monomode laser source showed that the linear diffuser generate a non periodic far field intensity distribution that was also observed by Wippermann et al [6] for chirped fly's eye condenser based beam homogenizers.…”

Section: Inspection and Characterizationsupporting

confidence: 74%

Fabrication and characterization of linear diffusers based on concave micro lens arrays

Bitterli¹,

Scharf²,

Herzig³

et al. 2010

Opt. Express

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Abstract:We present a new approach of beam homogenizing elements based on a statistical array of concave cylindrical microlens arrays. Those elements are used to diffuse light in only one direction and can be employed together with fly's eye condensers to generate a uniform flat top line for high power coherent light sources. Conception, fabrication and characterization for such 1D diffusers are presented in this paper.

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Section: Inspection and Characterizationsupporting

confidence: 74%

Fabrication and characterization of linear diffusers based on concave micro lens arrays

Bitterli¹,

Scharf²,

Herzig³

et al. 2010

Opt. Express

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“…In other words: every lenslet on the wafer can be designed to have its own position, orientation, size (mask #1), and focal length (mask #2). We used this enhanced design freedom in the randomization of arrays for homogenization [17], the channel-wise aberration correction of multichannel imaging optics [18] or simply the lateral arrangement of elements with different parameters on the same wafer [19]. A means to simulate -generalized‖ chirped or stochastic lens arrays in the ray tracing design and routines to calculate the corresponding mask data for each lenslet were implemented in our fabrication process [20].…”

Section: Mastering By Photolithographymentioning

confidence: 99%

Wafer-Level Hybrid Integration of Complex Micro-Optical Modules

et al. 2014

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A series of technological steps concentrating around photolithography and UV polymer on glass replication in a mask-aligner that allow for the cost-effective generation of rather complex micro-optical systems on the wafer level are discussed. In this approach, optical functional surfaces are aligned to each other and stacked on top of each other at a desired axial distance. They can consist of lenses, achromatic doublets, regular or chirped lens arrays, diffractive elements, apertures, filter structures, reflecting layers, polarizers, etc. The suitability of the separated modules in certain imaging and non-imaging applications will be shown.

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“…These peaks can only be avoided if the illumination is partly coherent or if the periodicity is avoided. Wippermann et al [10] described a solution for avoiding the periodic structure with the help of a so called chirped microlens array. Another way to temporally smooth the spiked profile is to use rotating random diffusers.…”

Section: Diffraction and Grating Effectsmentioning

confidence: 99%

Randomly varying micro-optical elements for the generation of uniform intensity profiles in coherent laser sources

et al. 2008

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A wide range of lasers from the UV to the IR are selected based on their optical power and spectral characteristics to match the particular absorption behavior for the material to be processed. Periodic microlens arrays are often used as multi-aperture integrators to transform the Gaussian or non-uniform beam profile into a homogenized intensity profile either in 1-D or 2-D distribution. Each microlens element samples the input inhomogeneous beam and spreads it over a given angular distribution. Incoherent beams that are either temporally or spatially incoherent can produce very uniform intensity profiles. However, coherent beams will experience interference effects in the recombination of the beams generated by each individual microlens element. For many applications, for example pulsed laser sources, it is not possible to use a rotating or moving element, such as a rotating diffuser, to circumvent the interferences resulting from the beam coherence. Micro-optical elements comprised of a randomly varying component can be used to help smooth out the interference effects within the far-field intensity profile.

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Beam homogenizers based on chirped microlens arrays

Cited by 76 publications

References 7 publications

Fabrication and characterization of linear diffusers based on concave micro lens arrays

Fabrication and characterization of linear diffusers based on concave micro lens arrays

Wafer-Level Hybrid Integration of Complex Micro-Optical Modules

Randomly varying micro-optical elements for the generation of uniform intensity profiles in coherent laser sources

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