Ultra‐Small Birefringence Continuous‐Tuning and Full‐Band Zero‐Order Waveplate Devices (Advanced Optical Materials 7/2026)

Zero-Order Waveplate Waveplates have attracted increasing attention due to their irreplaceable role in polarization optics. For a long time, zero-order waveplates exhibited ultra-thin machining and application difficulties because the birefringence of the crystal was not small enough. Through non-principal axis cutting, even materials with large birefringence can achieve appropriate birefringence values by adjusting the incident direction, thereby expanding the selection range of waveplate materials and achieving precise phase control of light waves in a wide spectral range, breaking the limitations of the inherent birefringence and transmittance band of a single material. More details can be found in the Research Article by Lijuan Chen, Zeliang Gao, and co-workers (DOI: 10.1002/adom.202502910).