Optical system for efficient tunable acousto-optic filtering of unpolarized supercontinuum radiation

Abstract

Subject of study. This study investigates the transmission and radiation power at the output of a tunable acousto-optical filtering system designed for unpolarized supercontinuum radiation. Aim of study. The primary aim is to develop a compact, highly efficient optical system that combines the ±1st diffraction orders of a tunable acousto-optical filter for filtering unpolarized supercontinuum radiation. Method. A novel approach is proposed for combining the two diffraction orders of an acousto-optical filter. This method employs a fiber pump combiner and chromatic shift compensator wedges. The proposed optical system was modeled and experimentally tested, with efforts made to minimize the impact of radiation instability and stray light on measurement accuracy. Main results. The results demonstrated the efficiency of the proposed optical system for filtering unpolarized supercontinuum radiation over a broad spectral range. The optical power at the system’s output increased by a factor of 2.2 compared with the use of a single diffraction order combined with a linear polarizer. Additionally, the system’s transmittance for combining the diffraction orders of the acousto-optical filter was measured at 78%. Practical significance. This optical setup offers a versatile solution for applications requiring tunable spectral filtering across a wide spectral range while minimizing power and polarization losses. The system is compact, easy to adjust, and can be integrated with the multi-frequency mode of an acousto-optical filter, enabling the transmission of complex spectral compositions, such as those required in colorimetry.