Integrated Double-Sided Random Microlens Array Used for Laser Beam Homogenization.

Area of Science:

• Optics and Photonics
• Laser Technology
• Materials Science

Background:

• Traditional double microlens arrays (MLAs) create periodic lattice distributions in homogenized laser spots, reducing uniformity for high-coherence beams.
• The periodicity of conventional MLAs leads to reduced uniformity in homogenized laser spots, particularly for high-coherence applications.

Purpose of the Study:

• To develop a monolithic and highly integrated double-sided random microlens array (D-rMLA) for improved laser beam homogenization.
• To overcome the uniformity limitations of traditional MLAs in high-coherence laser beam homogenization.

Main Methods:

• Fabrication of a D-rMLA by disturbing MLA periodicity with random apertures using a double-sided exposure technique for precise alignment.
• Integration of random microlens structures on both sides of a single substrate to form a monolithic D-rMLA.
• Experimental testing of the D-rMLA for laser beam homogenization at 650 nm (R), 532 nm (G), and 405 nm (B).

Main Results:

• The D-rMLA achieved high uniformity for RGB homogenized spots, reaching approximately 91% (R), 89% (G), and 90% (B).
• Energy utilization rates for the homogenized spots were approximately 89% (R), 87% (G), and 86% (B).
• The D-rMLA demonstrated effective laser beam homogenization across a wide wavelength range.

Conclusions:

• The developed D-rMLA structure significantly enhances laser beam homogenization and energy utilization.
• The monolithic and integrated design of the D-rMLA avoids alignment issues associated with discrete MLA installations.
• The D-rMLA is a promising solution for wide-wavelength laser beam homogenization applications.