Owing to the intriguing diffraction-free, self-accelerating, and self-healing properties, Airy beams have enormous potential in photonics applications, such as micromanipulation, microscopy, and optical interconnection. Either customary or flat optical methods for generating Airy beams, require that spatial beams pass through the optical elements, which thus requires long optical paths and precise alignment of the optical elements along the optical axis.
The team of Prof. Lin Chen from Wuhan National Laboratory for Optoelectronics proposes a silicon-integrated platform to generate Airy beams. By introducing the related concepts of holographic technology into integrated photonics, a physical model of the silicon-integrated holography enabled Airy beam emission is built with regarding the guided waves and Airy beams as grazing incident reference beams (RBs), and +1 order diffractive object beams (OBs), respectively. Considering that the amplitude profile of the TE0mode in the strip waveguide decays from the center to the edge, and the RB decays along the propagation direction due to the scattering, which somewhat follows the amplitude profile of the Airy beam, the hologram can be simplified as a pure-phase form.
The binary interferogram of the OB and the RB can serve as a shallow-etched holography grating and scatter guided wave into spatial waves by recovering the wavefront distributions of Airy beam. Within the telecommunication wavelengths, 2D Airy beam is demonstrated with a 20 μm×20 μm holography grating on strip waveguide. High-quality Airy envelop can be generated within the wavelength of 1490-1570 nm, and the broadband self-bending property of emitted Airy beam is demonstrated. Besides, the quality of the emitted Airy beam is robust to the etching depth error of grating. This result may inspire the design of compact and robust photonic components for special beam generation.
Recently, this work, titled as “Compact broadband silicon-integrated Airy beam emitter”, was published inOptics Letters.
Paper link:
https://www.osapublishing.org/ol/abstract.cfm?uri=ol-46-17-4084
Fig.1 The scheme of the silicon-integrated Airy beam emitter.
Fig.2 Bandwidth property of the proposed Airy beam emitter. (a) The normalized electric field intensity distribution of the generated 2D Airy beam for the different propagation distance z at the different wavelengths. (b, c) The coordinates of the electric field intensity peaks for the different wavelengths and z along the (b) x and (c) y directions.
