Improved homogenization of fly's eye condenser setups under coherent illumination using chirped microlens arrays

F. C. Wippermann; P. Dannberg; A. Bräuer; S. Sinzinger

doi:10.1117/12.700127

22 January 2007 Improved homogenization of fly's eye condenser setups under coherent illumination using chirped microlens arrays

F. C. Wippermann, P. Dannberg, A. Bräuer, S. Sinzinger

Author Affiliations +

Proceedings Volume 6466, MOEMS and Miniaturized Systems VI; 64660R (2007) https://doi.org/10.1117/12.700127
Event: MOEMS-MEMS 2007 Micro and Nanofabrication, 2007, San Jose, California, United States

Abstract

Fly's eye condensers are commonly used for the beam shaping of an arbitrary input intensity distribution into a top hat. The setup usually consists of a Fourier lens and two identical regular microlens arrays - often referred to as tandem lens array - where the second one is placed in the focal plane of the first microlenses. Due to the periodic structure of the regular arrays the output intensity distribution is modulated by equidistantly located sharp intensity peaks. In a chirped array, the inflexibility of a regular structure has been overcome. Hence, an array can be formed which is non-periodic and consequently the equidistantly located intensity peaks can be suppressed. A far field speckle pattern results with more densely and irregularly located intensity peaks leading to an improved homogeneity of the intensity distribution. In contrast to stochastic arrays, chirped arrays consist of individually shaped lenses defined by a parametric description of the cells optical function which can be derived completely from analytical functions. This gives the opportunity to build up tandem array setups enabling to achieve far field intensity distribution with an envelope of a top hat. We propose a new concept of a fly's eye condenser incorporating a chirped tandem microlens array for the generation of a top hat far field intensity distribution with improved homogenization under coherent illumination. Considerations for the design of the irregular micro lens arrays and measurements of far field intensity distributions obtained from first prototypes generated by reflow of photoresist are presented.

Citation Download Citation

F. C. Wippermann, P. Dannberg, A. Bräuer, and S. Sinzinger "Improved homogenization of fly's eye condenser setups under coherent illumination using chirped microlens arrays", Proc. SPIE 6466, MOEMS and Miniaturized Systems VI, 64660R (22 January 2007); https://doi.org/10.1117/12.700127

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available