One-step real-virtual combined reflection hologram: a 4f relay approach

The production of conventional optical reflection holograms can be classified into the one-step method or the two-step method. In the one-step method, only the diverging light of an object can be recorded, and the reconstructed scene is a virtual one behind the recording medium. In the two-step method, the diverging light or the converging light can be recorded alternatively. However, the process is complicated considering double exposures. The object is first imaged by a 4f system, and then the interference patterns are recorded by single exposure. The reconstructed image can be either a virtual image behind the recording medium or a real image in front of the recording medium. The ideal imaging property of a 4f system has been demonstrated theoretically, and the proposed method has been verified experimentally.