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ABSTRACT Ince‐Gaussian (IG) modes are a complete and orthogonal set of solutions to the paraxial wave equation in elliptic coordinates representing a continuous transition between Hermite‐Gaussian modes and Laguerre‐Gaussian modes. Chip‐scale platforms to generate IG beams have great significance for various applications, including optical trapping and micromanipulation of particles, optical communication, and quantum optics. On the other hand, materials with high optical anisotropy are crucial for building polarization‐sensitive optical devices. In this context, niobium oxide dihalides are a new class of ferroelectric materials exhibiting strong, tailorable, and highly anisotropic second‐harmonic generation responses. Here, we report the generation of highly anisotropic second‐harmonic IG beams using binary grating holograms patterned on ultrathin niobium oxide dibromide (NbOBr2) flakes. Both even and odd IG beams with different mode indices are generated by encoding the phase profiles of the beams into the holograms. According to the polarization‐dependent second‐harmonic generation responses, the relative magnitudes of the second‐order nonlinear susceptibility elements of NbOBr2crystal are extracted. The results presented here provide new directions for generating complex optical beams with potential applications in classical and quantum photonic integrated devices.
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This content will become publicly available on December 1, 2026
Anisotropic Second‐ and Third‐Harmonic Hermite–Gaussian Beam Generation with NbOI 2 Holograms
Hermite–Gaussian (HG) modes are an orthogonal set of solutions to the paraxial wave equation possessing distinct spatial intensity variations, which are important in many optical applications. Here, anisotropic second‐ and third‐harmonic HG beam generation is demonstrated with ultrathin niobium oxide diiodide (NbOI2) grating holograms to produce the nonlinear HG01and HG10modes. It is shown that the generated second‐harmonic HG modes exhibit a high anisotropy ratio reaching a large value of 14.95, while the simultaneously generated third‐harmonic HG modes have an anisotropy ratio up to 4.85. The relative magnitudes of the second‐ and third‐order nonlinear susceptibility tensor elements of NbOI2crystal are extracted by analyzing the polarization‐dependent nonlinear emission. These demonstrations provide new opportunities for building functional polarization‐sensitive nonlinear optical devices used for future integrated photonic chips, optical computing, and optical communication.
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- PAR ID:
- 10684368
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Advanced Photonics Research
- Volume:
- 6
- Issue:
- 12
- ISSN:
- 2699-9293
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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