AI Article Synopsis
- A new method for generating orbital angular momentum (OAM) modes using a fiber Bragg grating (FBG) was both proposed and tested, utilizing off-axis beam incidence.
- The FBG, created with a femtosecond laser, allows the input beam to be transformed into high-order modes, which can then be shaped into ring-shaped OAM modes by adjusting the beam’s off-axis position.
- Experimental results showed that the OAM mode order depends on the FBG resonant wavelength, while the topological charge's sign is influenced by the beam’s displacement, achieving high purity OAM modes of orders ±1 and ±2.
Article Abstract
In this Letter, a method for orbital angular momentum (OAM) mode generation is proposed and experimentally demonstrated using a fiber Bragg grating (FBG) and off-axis incidence. The FBG fabricated by a femtosecond laser was used to couple the incidence beam into backward high-order modes. The generated modes were then reformed into ring-shaped OAM modes by adjusting the off-axis displacement of the input beam. The intensity distribution, phase vortex, and mode purity of the output light were experimentally investigated. Results indicates that the order of the generated OAM modes is dependent on the resonant wavelength of the FBG, and the sign of the OAM topological charge is determined by the displacement value of the off-axis incident light. In the experiment, ±1- and ±2-order OAM modes were achieved and confirmed, with purities as high as 90%, 91%, 89%, and 88%, respectively.
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| http://dx.doi.org/10.1364/OL.410277 | DOI Listing |
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