NEW! SC318 Laser Beam Combining: Theory and Methods

Tuesday, May 6, 8:30 a.m. - 12:30 p.m.
James R. Leger; Univ. of Minnesota, USA

Level: Beginner (no background or minimal training is necessary to understand course material)

Course Description
The performance of conventional high power lasers is often compromised by one or more physical effects, limiting the maximum power obtainable from a single lasing element. To increase the radiance from these individual elements, laser beam combining can be employed to convert the output light from several lower-power modules into a single, high-power, high radiance beam.

This Short Course emphasizes general beam combining principles relevant to all laser systems, and analyzes performance characteristics from several beam combining approaches. The practicing engineer and technical manager will be introduced to a wide variety of beam combining methods. Incoherent beam combining attempts to maximize the radiance of an array of incoherent sources. The theoretical limits of this approach will be derived, and a design methodology developed to achieve maximum radiance. Spectral and polarization beam combining employ wavelength or polarization sensitive elements to sum laser power. Several practical issues of this technique will be discussed, and specific systems described. Coherent beam combining is introduced by exploring methods of establishing mutual coherence across laser arrays. The properties and characteristics of these coherent techniques are quantitatively analyzed using simple modal theories. Methods of converting arrays of coherent beams into a single beam are explored, and the sensitivity of these approaches to path length errors investigated. Finally, nonlinear approaches to beam combining are described.

Benefits and Learning Objectives
This course should enable you to:

• Describe the requirements for laser beam combining of all types.
• Estimate the optimum brightness enhancement achievable from incoherent combining.
• Design an ideal incoherent beam combiner.
• Design fiber optic spectral beam combiners and estimate performance limitations.
• Compare different architectures for establishing mutual coherence across laser arrays.
• Determine the effects of path length errors on beam combining performance.
• Design optical systems to convert coherent arrays of laser beams into a single beam.
• Describe the performance characteristics of several laser systems that utilize beam combining.

Intended Audience
The course is designed for students, engineers, scientists, and technical managers who are interested in understanding the basics of laser beam addition. No advanced knowledge of laser systems is assumed.

Instructor Biography
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, metrology and imaging systems. Leger is a fellow of the OSA, IEEE and SPIE, and winner of the 1998 OSA Fraunhofer Award. He is a former topical editor for Optics Express and Applied Optics, and is a past member of the Board of Directors of OSA. He is currently on the Steering Committee of CLEO.