High-performance dichroic dye-doped flexible cholesteric polymer film optical filter for laser protection application

High-performance optical filters are quite useful in laser protection application that is critical in military and civilian fields for protection of human eyes and photonic devices. However, most existing technologies are often angle-dependent and complicated, which hinder the useful range of real-time application. Here, we report the development of a dichroic dye-doped flexible cholesteric polymer film optical filter with double-layer structure consisted of two films with opposite handedness for laser protection application. The fabricated films exhibit high and stable optical density (>4.6) in large angle range from 0 to 70°, indicating a good angle-independence. The proposed films show excellent stability in a broad temperature range from -100 °C to 100 °C, and high mechanical stress up to 9.8 × 105 Pa. As a laser protection, the optical filter can resist pulse pump energy up to 110 mJ/pulse, showing a high damage threshold. The flexible and free-standing film optical filters as laser protection device are integrated by simple fabrication, excellent stability to temperature and mechanical stress, angle-independence, high optical density, and good visibility simultaneously, showing dramatically application potential in laser protection and other flexible photonic devices.