Photoaligned twisted nematic liquid crystal elements for multi-channel polarization and electro-optical encryption

Liquid crystals (LCs) with anisotropic nanostructures can modulate amplitude and polarization of beam simultaneously, making them essential for displays, optical devices, and particularly in photoalignment-driven optical encryption. In this work, a multi-channel polarization and electro-optical encryption based on photoaligned twisted nematic liquid crystal (TNLC) elements is proposed. Multi-channel image encryption is achieved by controlling the polarization distribution through TNLC. The two plaintexts are converted into ciphertexts and record with their corresponding secret keys in the same channels. To further enhance security, a distributed encryption approach was also employed, with the ciphertext and secret key recorded separately in different channels. The optical encryption system utilizes a dual encryption: polarization acts as the first key to decrypt the ciphertext, while the corresponding decryption method serves as the second key to fully unlock the encrypted information. In addition, the electro-optic effect of LC molecules enables dynamic switching between different encryption channels, which providing a new degree of freedom for optical encryption. The proposed photoalignment-driven encryption offers enhanced security, robust performance, and broadband working windows, paving the way for innovation and broader applications in optical encryption.