Light Beams With Phase Modulated And Their Applications

In recent years, phase-modulated light beams have been drawn considerableattention due to the unique feature compared with normal light beams. Vortex beamsand Airy beams are typical phase-modulated light beams. Each photon of vortexbeams carries orbital angular momentum (OAM). Vortex beams have importantapplications in many fields, such as optical information encoding and transmission,particle manipulation and trapping, etc. Airy beams are extremely specialnon-diffracting beams due to their freely acceleration during propagation. Airy beamshave the ability to remain diffraction-free during long distances while they tend tofreely accelerate during propagation. Phase-modulated light beams have been widelyused in many fields. Partially coherent light beams are a kind of phase-modulatedlight beams whose phase and amplitude change over time. Partially coherent lightbeams not only have high brightness as coherent light beams, but they are lessinfluenced during propagation in turbulent atmosphere and random media. Therefore,for the investigation on generation and propagation properties of thesephase-modulated beams have important theoretical and practical significance.In this paper, we investigate the properties of vortex beams, Airy beams andpartially coherent beams. The influences on vortex beams and Airy beams ofcoherence degree are also studied. Moreover, we can generate non-uniformlycorrelated partially coherent light beams in experiment. To the best of our knowledge,there is no experimental investigation on non-uniformly correlated partially coherentlight beams before this.1. We report the experimental realization of non-uniformly correlated partiallycoherent light (NUCPCL) beams by passing laser beams through a phase-only spatiallight modulator (PSLM). The characteristics of NUCPCL beams whose coherence is ofGaussian distribution as well as inverse Gaussian distribution are studied theoreticallyand experimentally. It is shown that the experimental observations are in agreementwith our theoretical analysis. NUCPCL beams may have some applications in opticalmanipulation etc. 2. Based on the cross-spectral density function of Gaussian-Shell Model andHuygens integral, the expression of partially coherent Airy beam was derived. Thenon-diffraction and acceleration characteristics of partially coherent Airy beam weretheoretical studied and experimental observed. The experimental observation wasconsistent with the theoretical prediction. Furthermore, the non-diffraction distance andthe transversal acceleration decrease with decreasing coherent length.3. Partially coherent vortex beams are generated by the illumination of high-powerred-color light-emitting diodes. We investigate the influence of correlation property ofpartially coherent vortex beams on intensity distribution. The correlation property ofpartially coherent vortex beams are modulated by adjusting the propagation distanceof the incident light. Effects of the topological charge and propagation distance ofvortex beams on the intensity are also studied. Experiment results are consistent withtheoretical simulations.