Optimization-based Techniques for Laser Shaping Optics

Previous efforts have shown that optimization-based techniques, particularly genetic algorithms, can be used to effectively design beam shaping systems for several classes of problems. These techniques have used external programs to perform the optimization, which allow a great deal of optimization flexibility. However, the external program must be understood and tuned for beam shaping applications. For many problems, the flexibility of an external program is not required. This work shows that the internal optimization routines in a typical lens design program can perform effective optimization of several classes of beam shaping systems. In addition, previous beam shaping merit functions have used a large number of rays, typically 200, to perform the optimization. Several pieces of data must be recorded for each ray. This results in a fairly lengthy merit function evaluation by the lens design program. This work shows that by setting up certain problems using upfront geometrical considerations, reasonable optimizations can be obtained with as few as 20-40 rays being traced. Example problems are presented, including the merit functions used. Guidance is provided for the designer interested in picking appropriate parameters and optimization routines for some typical problems.

Section: Previous Optimization-based Methodsmentioning

confidence: 99%

Section: Previous Optimization-based Methodsmentioning

confidence: 99%

<title>Laser beam shaping via conventional design software</title>

Holswade¹,

Dickey²

2001

“…Genetic algorithm (GA) optimization methods have been shown to work well designing laser beam shaping systems, when the merit function contains both discrete and continuous parameters. 42 As an example of a more complex problem-one difficult to solve using more conventional methods-the GA technique has been used to design a gradient index (GRIN) laser beam shaping system. Wang and Shealy 59 solved this problem using a differential-equation design method.…”

Section: Genetic Algorithm Optimization Methodsmentioning

confidence: 99%

“…Optimization-based techniques, such as, genetic algorithms (GA), have also been shown to be effective methods for design of laser beam shaping systems. 42 Three applications -a two-plano-aspheric lens system for shaping a rotationally symmetric Gaussian beam, a two-mirror system with no central obscuration for shaping an elliptical Gaussian input beam, and a three-element GRIN system with spherical surfaces for shaping a rotationally symmetric Gaussian beamare discussed. These applications have been selected to illustrate how the geometrical methods for optical design of laser beam shaping systems are applied to a range of configurations.…”

mentioning

confidence: 99%

Historical perspective of laser beam shaping

Shealy

2002

An overview of the history and current practices of laser beam shaping is presented. When diffraction effects are not important, geometrical methods for laser beam shaping (ray tracing, conservation of energy within a bundle of rays, and the constant optical path length condition) can be used to determine system configurations, including aspheric elements and spherical-surface GRIN lenses, which are required to transform an input laser beam profile into a more useful form of illumination. This paper also summarizes applications of these techniques to the optical design of a two-planoaspheric lens system for shaping a rotationally symmetric Gaussian beam, a two-mirror system with no central obscuration for shaping an elliptical Gaussian input beam, and a three-element spherical surface GRIN system for shaping a rotationally symmetric Gaussian beam.

“…Optimization-based techniques, such as, genetic algorithms (GA) have also been shown to be effective methods for design of laser beam shaping systems. 19 Section 3 summarizes three applications of this theory to the design of laser beam shaping systems -a two plano-aspheric lens system, a two-mirror configuration with no obscuration, and a threeelement GRIN lens system.…”

Section: Introductionmentioning

confidence: 99%

Optical design of laser beam shaping systems

Shealy

2002

An overview of the history and current practices of laser beam shaping is presented. When diffraction effects are not important, geometrical methods for laser beam shaping (ray tracing, conservation of energy within a bundle of rays, and the constant optical path length condition) can be used to determine system configurations, including aspheric elements and spherical-surface GRIN lenses, which are required to change the intensity profile into a more useful form. Geometrical optics-based design methods are presented for shaping both rotationally and rectangular symmetric laser beam profiles. Applications of these techniques include design of a two-plano-aspheric lens system for shaping a rotationally symmetric Gaussian beam, a two-mirror system with no central obscuration for shaping an elliptical Gaussian input beam, and a three-element GRIN system for shaping a rotationally symmetric Gaussian beam.