Proposed use
The invention can be used to create new bespoke vortex lasers and could retrofit existing lasers (e.g. solid-state, fibre) to provide vortex output. Higher-order vortices and mode superposition can be generated if the laser operates itself on an internal mode that is vortex: useful for optical trapping, levitation and manipulation of micro- and macro-particles.
Vortex beams can enhance the efficiency of laser manufacturing processes, provide advantages in free-space communications being more robust to atmospheric turbulence and offer improved data encryption.
Problem addressed
Relatively little progress has been made for high power vortex generation and even less for high efficiency, robust and compact systems. The generation of vortex beams is predominantly done by converting a Gaussian beam externally to the laser using mode conversion techniques. The spatial light modulator (SLM) has become a primary technology for generating almost any light pattern one could want, but they have very low power-handling capability and high expense which are major limitations.
Technology overview
The invention is a low-cost, high-power and high efficiency new methodology for vortex creation: an interferometric output coupling methodology that spatially transforms the output of the laser.
Benefits
- Vortex laser beam generation at much higher power and pulse energy than most commonly used mode transformation elements (SLMs, Q-plates)
- Direct generation from a laser with high efficiency
- Enables the creation of new bespoke vortex lasers
- Allows existing non-vortex (Gaussian) laser systems to be directly retro-fitted into a vortex laser with little adaptation
- Handedness of the vorticity can be controlled, selected or switched
- Output transmission of the laser into the vortex mode can be continuously controlled allowing optimisation of power and efficiency of system
- Selectivity of the interferometric output coupler can “clean-up” the quality of the internal laser mode during the vortex generation
- Low-cost vortex output coupler
Intellectual property information
Patent : PCT/GB2019/052729
Links to published papers
Geberbauer, J. W. T., Kerridge-Johns, W. R., & Damzen, M. J. (2020). Q-switched laser with self-mode-filtering interferometric vortex output coupler. OSA Continuum, 3(2), 204-213.
Damzen, M. J., Kerridge-Johns, W. R., & Geberbauer, J. W. T. (2019). Vortex mode transformation interferometry. Journal of Optics, 22(1), 015604.
Kerridge-Johns, W. R., Geberbauer, J. W. T., & Damzen, M. J. (2019). Vortex laser by transforming Gaussian mode with an interferometric output coupler. Optics express, 27(8), 11642-11650.
