Significance With the advancement of information technology, humans have entered the mobile Internet age. Moreover, surging communication services have resulted in an exponential growth of the capacity and rate of communication systems, spurring the research and development of an ultrahigh-speed and ultralarge-capacity optical communication system. However, high-speed optical signals are susceptible to channel dispersion and nonlinearity, increasing the bit error rate at the receiver and limiting further improvement of the communication rate. Furthermore, as the signal rate increases, the bandwidth demand for the transmitter and detector in the communication system also increases, increasing the overall system cost. To address these challenges, conventional optical communication transmission and detection methods must be improved further to enhance the efficiency of optical communication.
Ghost imaging is a novel dual-arm imaging technology, which has attracted considerable research attention. A correlation algorithm between two spatially separated light beams can be used to reconstruct the spatial intensity information of the target object. The object is illustrated by one beam called the object beam, and the transmitted or reflected light is collected using a bucket detector with no spatial resolution, yielding the total light intensity value. The other beam called the reference beam does not interact with the target object and is directly received using a detector with spatial distribution. Neither of the detectors can produce an image of the object on their own; however, the object will appear after correlation operation for these two beams. Ghost imaging has aroused great interest of researchers because of its unique nonlocality, which has a significant potential application value in noisy and turbulent scenarios where the application of conventional imaging methods is limited.
Ghost imaging has recently been extended from the spatial domain to the temporal domain by investigating the duality of light propagation in space and time, i.e., the correspondence between the diffraction of a light beam and the dispersive propagation of a short optical pulse. Temporal ghost imaging has been proposed in theory and verified in experiment. To reconstruct a temporal object by correlating operation, different temporal sequences must be illuminated and the cumulative energy of the illuminated light must be collected using a bucket detector. Temporal ghost imaging uses a slow-speed detector to detect high-speed optical signals and is insensitive to the damage between the signal and detection. Therefore, it is a promising method for optical signal detection and recovery.
Progress Since the implementation of temporal ghost imaging in an optical fiber-based system (
Further, we proposed a dual encryption scheme based on the micro-light-emitting diode (micro-LED) operating ultra bandwidth and a computational temporal ghost imaging algorithm, which was verified in a visible light communication system (
Conclusions and Prospect In conclusion, temporal ghost imaging opens novel perspectives for dynamic imaging of ultrafast signals in various scenarios; however, it still needs further research and improvement. The development of hardware devices and improvement of the calculation algorithms will promote the development and application of temporal ghost imaging in optical communication, information security and transmission, equipment performance improvement, and other fields.