Beamshaping for high-power lasers using freeform refractive optics

Roy McBride; Natalia Trela; Matthew O. Currie; Duncan Walker; Howard J. Baker

doi:10.1117/12.2040660

20 February 2014 Beamshaping for high-power lasers using freeform refractive optics

Roy McBride, Natalia Trela, Matthew O. Currie, Duncan Walker, Howard J. Baker

Proceedings Volume 8963, High-Power Laser Materials Processing: Lasers, Beam Delivery, Diagnostics, and Applications III; 89630C (2014) https://doi.org/10.1117/12.2040660
Event: SPIE LASE, 2014, San Francisco, California, United States

Abstract

High power laser beamshapers based on lens arrays are widely used to generate square, rectangular or hexagonal flat-top far-field beam profiles. These devices can provide high efficiency and excellent brightness preservation, but offer a limited range of far-field profiles and can suffer from diffraction-related artefacts when used with spatially-coherent beams. Diffractive optical elements (DOE) offer a far wider range of far-field profiles, and better speckle behavior, but bring performance trade-offs in terms of brightness, efficiency, scattered power and residual zeroth-order power. Freeform refractive optics offer additional choices in the design of high power laser beamshapers. Freeform lens arrays offer a wider range of beam profile options than that available from catalogue lens array parts. Freeform field mapping beamshapers can generate a wide range of application-specific beam profiles with high efficiency and, where required, minimal reduction in brightness. More complex quasi-random freeform surfaces can act as a pseudorandom refractive intensity mapping element (PRIME), providing a level of beamshaper design flexibility closer to that of DOEs, but without the related high-order scatter and zeroth order leakage. We describe the design and implementation of these different types of refractive beam shaper in fused silica, using PowerPhotonic’s direct-write freeform fabrication process. This is ideal for use in high-power laser systems, where high damage threshold and low loss are essential. We compare and contrast the performance, benefits and limitations of these types of beamshaper, and describe how to select the ideal beamshaper type based on source coherence properties and application beam profile requirements.

Citation Download Citation

Roy McBride, Natalia Trela, Matthew O. Currie, Duncan Walker, and Howard J. Baker "Beamshaping for high-power lasers using freeform refractive optics", Proc. SPIE 8963, High-Power Laser Materials Processing: Lasers, Beam Delivery, Diagnostics, and Applications III, 89630C (20 February 2014); https://doi.org/10.1117/12.2040660

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