Diamond Brillouin vortex beams

First free-space high-order vortex

Raman-assisted pumping generates single-frequency Brillouin lasing in a diamond cavity; an external mode converter yields vortex beams with topological charges 1–4 and linewidths of 4.5–4.9 kHz, offering a new source of highly coherent structured light.

Chen, Hui · 77114696 · Zhu, Zhihan · Wang, Yulei · Lü, Zhiwei · Omatsu, Takashige · Mildren, Richard P.

APL Photonics 2025

Specifications

Vortex beam linewidth

{'zh': '4.5–4.9', 'en': '4.5–4.9'} kHz

Topological charge

{'zh': '1–4', 'en': '1–4'}

Brillouin laser wavelength

{'zh': '1240', 'en': '1240'} nm

Advantages

Single-frequency output

The vortex beam linewidth is only 4.5–4.9 kHz, more than 1.3 times narrower than the fundamental, providing a highly coherent source.

High-order vortex

Using an extra-cavity astigmatic mode converter, topological charges up to 4 are obtained, marking the first free-space high-order Brillouin vortex beam generation.

Cascaded pumping

The first-order Stokes field from stimulated Raman scattering serves as an intermediate pump to drive Brillouin lasing, eliminating the need for direct external pumping.

Applications

• Optics and Photonics：Provides a highly coherent vortex source for structured light research.
• Precision Measurement：Narrow linewidth enables high-resolution interferometric measurements.
• Optical Communication：Vortex beams add an extra degree of freedom to enhance communication capacity.
• Optical Tweezers and Micromanipulation：Orbital angular momentum can trap and rotate microscopic particles.