Chirped surface gratings on azopolymers from digital holographic photomorphing

Azomaterials are a powerful class of photoactive materials capable of surface morphing under structured light, enabling fully reprogrammable micro-optical elements. We demonstrate the fabrication and dynamic reconfiguration of linearly chirped diffraction gratings via azopolymer-based photomorphing using digital holographic lithography. This method allows continuous control over the spatial distribution of the grating vectors, encoding a wide range of periodicities within a single exposure, an achievement typically hampered by conventional two-beam interference techniques. Real-time monitoring of diffraction efficiency also boosts direct optimization of lithographic parameters, ensuring agreement with theoretical predictions of scalar diffraction theory. The full reconfigurability of the azopolymer surface also allows dynamic tuning of the diffraction orders, including both the angular and spectral distribution as well as the power ratio of the diffracted light. These capabilities further establish our approach as a versatile platform for advancing azopolymer-based reconfigurable diffractive optics.