Monolithic optical components for splitting of high-power beams

Abstract

Highly efficient beam splitters are important for a variety of high power laser applications. We prove different approaches like aperture and amplitude splitting for practicability for single- and multimode laser sources. Combining of micro- and macro-optical fabrication technologies allows novel monolithic free form splitting components with implemented segmented or stepless diffractive optical surfaces. The monolithic components are robust, compact and low weight and easy in handling. Here, we present two monolithic components: a segmented free form 1-to-17 beam splitter for fibre coupled lasers and a diffractive 1-to-11 beam splitter for single mode lasers with peak-to-peak pitch of 1.25mm and 0.8mm, respectively. The optical designs, the manufacturing of the prototypes as well as surface and performance measurements are reported. The prototypes from Fused Silica and Calcium Fluoride are designed for 532nm and 1064nm wavelength. Simulations show efficiencies larger than 98% and peak-to-peak non-uniformity below±3.2%. First laboratory results confirm efficiencies of < 95% and peak-to-peak non-uniformity of less than ±5%

Sensitivity analysis and optimization method for the fabrication of one-dimensional beam-splitting phase gratings

“…Binary phase gratings [4][5][6], continuous phase gratings [6][7][8], and refractive lenslet arrays [9] also accomplish phase beam-splitting. Continuous phase gratings are of interest, since they yield the highest efficiencies out of all beam-splitting methods [10].…”