Abnormal Linear Dichroism in Anisotropic Van der Waals Crystal CrOCl Revealed by Phase‐Dependent Polarized Raman Scattering

Within angle‐resolved polarized Raman spectroscopy (ARPRS) experiments, ensuring accurate configurations is crucial for obtaining reliable results, especially when dealing with anisotropic materials like CrOCl with anisotropic crystal structure and phonon properties. However, comprehensive understanding of phase‐dependent ARPRS and the calibration of phase angle on anisotropic phonon modes from a crystallographic perspective are still lacking. Herein, detailed investigation on phase‐dependent ARPRS and looked into the anisotropic photo‐phonon interaction in CrOCl through in situ ARPRS is conducted. The Raman tensors and crystal orientation are acquired under two typical configurations. Phase‐dependent ARPRS are thoroughly analyzed for the calibration of analyzer deviation. The anomalous anisotropic response in phase‐dependent ARPRS is closely related to the intrinsic linear dichroism (LD) effect in CrOCl, which is further confirmed by angle‐resolved polarization absorption. Moreover, the strong localized rules for various parallel energy bands of CrOCl have generated anomalous LD conversion effect near 470 nm, which expands the potential application of CrOCl in polarization‐wavelength selected devices. This findings can offer in‐depth comprehension on the anisotropic phonon physics of CrOCl and a feasible approach to utilize phase‐dependent ARPRS for probing the undiscovered abundant photo‐induced effects in low‐symmetry 2D materials. Angle‐resolved polarized Raman spectroscopy (ARPRS) of CrOCl under two typical and accurate configurations is systematically investigated for reliable crystal orientation. The phase‐dependent ARPRS analysis emphasizes the importance of eliminating the analyzer angular deviation. 3D ARPRS reveals the high sensitivity of phase‐dependent ARPRS in detecting LD‐related effects. These results offer in‐depth comprehension on precise controlling configurations for probing the photo‐induced effects.