Chiral Lead‐Free Hybrid Organic‐Metal Halides for Thermally Switchable Nonlinear Optics

Why It Matters

The lead‑free platform removes toxic materials while delivering superior damage resistance, accelerating adoption of nonlinear optics in sustainable integrated photonics. Its thermally switchable SHG opens new avenues for dynamic on‑chip light modulation.

Key Takeaways

• Lead-free antimony chiral microplates replace toxic lead
• Drop-casting yields orientation‑controlled, highly crystalline plates
• Laser damage threshold exceeds 133 mJ cm⁻²
• Thermally induced reversible SHG switching demonstrated
• Enables chip‑scale nonlinear photonic integration

Pulse Analysis

The rapid expansion of optoelectronic technologies has long relied on hybrid organic‑inorganic metal halides for their strong nonlinear optical response. However, the majority of high‑performance compounds contain lead, raising environmental and health concerns and limiting their laser‑damage thresholds. Recent research has turned to antimony as a non‑toxic alternative, leveraging its similar electronic configuration to maintain the desirable band structure while improving material stability. By eliminating lead, these new chiral halides align with stricter regulatory standards and broaden the commercial viability of nonlinear photonic components.

The study introduces a solvent‑assisted drop‑casting technique that exploits surface‑energy gradients to grow substrate‑supported microplates with precise orientation control. This approach yields highly crystalline chiral antimony halides that preserve bulk second‑harmonic generation efficiency and exhibit an unprecedented laser‑damage threshold exceeding 133 mJ cm⁻². Moreover, the material undergoes a reversible lattice phase transition near ambient temperatures, enabling thermally induced switching of the SHG signal on the micro‑nano scale. Such dynamic control combines static optical performance with active modulation, a rare combination in current nonlinear materials.

These capabilities position antimony‑based chiral halides as strong candidates for next‑generation chip‑scale nonlinear photonic circuits, where high damage tolerance and reconfigurable functionality are critical. Integrated frequency‑doubling modules, on‑chip optical switches, and quantum light sources can now be designed without the liability of lead, simplifying manufacturing and reducing waste. As the industry pushes toward greener photonics, the demonstrated thermal SHG switch offers a low‑power route to dynamic light routing, potentially accelerating adoption in telecommunications, sensing, and computing platforms. Continued scaling of the drop‑casting process will be key to commercial deployment.