Improved single-random-phase holographic encryption using double-phase method

• Published in: Optics communications 2019-07, Vol.443, p.19-25
• Main Authors: Chang, Ke-Ming, Chen, Chun, Wang, Jun, Wang, Qiong-Hua
• Format: Article
• Language: English
• Subjects: Double-phase method; Holographic encryption; Phase-only hologram
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2019.03.016

An improved single-random-phase holographic encryption (SRPHE) is proposed by using double-phase method and demonstrated by a spatial light modulator (SLM). Different from the conventional SRPHE using Fresnel diffraction and the bidirectional error diffusion method, the proposed SRPHE employees the angular spectrum diffraction and double-phase method to generate a phase-only hologram, and the phase-only hologram is encrypted into ciphertext by multiplying a single random phase mask. When the ciphertext is modulated by the conjugate of the random phase mask and loaded to a SLM, the decrypted image can be achieved successfully. The improved SRPHE has two advantages of better quality of the decrypted image, and lower time-cost of hologram generation, which is compared with the conventional SRPHE. Numerical simulations and optical reconstruction results have been carried out to verify the validity of the proposed SRPHE. •Proposing an improved single-random-phase holographic encryption (SRPHE).•Hologram generating by the double-phase method in the proposed SRPHE.•Good quality of decrypted image and low time-cost of hologram generation in the proposed SRPHE.•The easy optical reconstructing of source image without complex optical equipment.