SC157 - Laser Beam Analysis, Propagation, and Spatial Shaping Techniques
Sunday, 15 May
08:30 - 12:30
Short Course Level: Advanced Beginner
James Leger; Univ. of Minnesota, USA
Short Course Description:
The propagation and focusing properties of real laser beams are greatly influenced by beam shape, phase distortions, degree of coherence, polarization, and aperture truncation effects. The ability to understand, predict, and correct these real-world effects is essential to modern optical engineering. Attendees of this course will be introduced to a variety of techniques for measuring and quantifying the important characteristics of real laser beams, be able to calculate the effects of these characteristics on optical system performance, and explore a variety of beam shaping techniques to optimize specific optical systems.
The course starts with a basic and intuitive description of Gaussian beam characteristics from an ideal laser. These concepts are extended to non-Gaussian beams (e.g. high-order Hermite Gaussian beams, top-hat shapes, laser arrays, and non-diffracting beams) and the relative merits of various beam shapes are discussed. The properties of optical vortex beams, cylindrical vector beams, and orbital angular momentum are then explored. Beam characterization methods such as M2, Strehl ratio, and TDL are reviewed. Simple expressions for estimating the effects of laser aberrations and coherence on beam focusing and propagation are developed. Coupling of light into single and multi-mode fibers, as well as far-field light concentration limits are explored as real-world examples. The constant radiance theorem and étendue are employed as engineering tools to optimize optical design, and simple analytical tools are presented to estimate the effects of spatial beam shape, phase aberrations, and coherence on beam concentration. The course ends with a description of internal and external cavity beam shaping techniques using phase and polarization modulation.
Short Course Benefits:
This course will enable participants to:
- measure the quality of a laser beam using several methods
- interpret the meaning of various laser specifications
- understand Gaussian laser beam properties from an intuitive standpoint
- predict the propagation and focusing properties of non-ideal and aberrated laser beams
- determine the concentration limits of a light field
- design optimal beam concentration optics
- compare different beam profiles for specific applications and calculate ideal performance
- design beam shaping optics using polarization and phase manipulation
Short Course Audience:
This course is designed to provide laser engineers, optical system designers, and technical management professionals with a working knowledge of laser beam characterization, analysis, and modification. Physical and intuitive explanations of most topics are designed to make the concepts accessible to a wide range of participants.
James Leger is the Cymer Professor of Electrical and Computer Engineering at the University of Minnesota. His previous work at MIT Lincoln Laboratory and current research concerns diffractive and microoptics applied to lasers and electro-optic systems. Prof. Leger is a fellow of OSA, IEEE, and SPIE, and winner of the 1998 OSA Fraunhofer award. He is also a member of the academy of distinguished teachers, and has been awarded several honors for his teaching. He is currently the Editor-in-Chief of Optics Express and has previously served in the Director at Large position on the OSA Board of Directors.