We propose what we believe is a new method for color image encryption by use of wavelength multiplexing based on lensless Fresnel transform holograms. An image is separated into three channels: red, green, and blue, and each channel is independently encrypted. The system parameters of Fresnel transforms and random phase masks in each channel are keys in image encryption and decryption. An optical color image coding configuration with multichannel implementation and an optoelectronic color image encryption architecture with single-channel implementation presented. The keys can be added by iteratively employing the Fresnel transforms. Computer simulations are given to prove the possibility of the proposed idea.

A new method is proposed in this paper for the synthesis and encryption of information with digital holography technique and virtual optics. By using a three-step phase-shifting interferometry, the fused or subtracted digital hologram can be calculated from different interference patterns. To protect the digital data that can be transmitted through communication channel, an encryption approach based on virtual optics is also proposed. The encryption method proposed is based on extended fractional Fourier transforms. Both the encryption and decryption processes are performed in all-digital manner. The encrypted data and the synthesized data reconstructed numerically also can be stored and transmitted in the conventional communication channel. Numerical simulation results are given to verify the proposed idea.

Nano-carbon as lighting source is demonstrated in this paper. The characterized nano-radiation from nano-carbon, excited by different lasers in vacuum, is observed when laser intensity is over a threshold. With lower excitation threshold and smaller white light source, nano-carbon is more applicable to be as lighting system than the others in scientific experiments. White light emission of nano-carbon induced by more practicable electromagnetic excitation (microwave) is also demonstrated, which is caused by the faradic heating of the metal substrates, with molecular spectra and better color rendering. Lighting systems comprised of nano-carbon may become one of the considerable directions in optics.