含负折射率平板介质中艾里高斯光束的传输特性

Propagation Properties of Airy Gaussian Beam Through Slab System Contained Negative Index Materials

摘要:

基于光学传输矩阵,结合柯林斯光学衍射公式,研究了艾里高斯光束在无损和有损含负折射率平板介质中传输时,其侧面光强分布图景演化特征。结果表明,当右手材料和双负材料折射率值恰好相反,并且左、右两侧右手单元长度之和等于双负单元长度时,可以实现输出面光强的完美还原;当双负材料折射率绝对值增大时,实现光强还原所需中间双负单元长度也越长,反之,绝对值减小时,长度越短;对于有损介质,电、磁振荡因子越小,输出光波性能越良好。进一步探究了ζ因子和指数截断因子a对这类光波传输特性的影响,其中,ζ因子不会影响艾里高斯光束的固有性质,但ζ越小,自弯曲特性越明显,并且主、旁瓣的径向尺寸都随ζ的减小而成倍减小;a因子可以调控光波的传输轮廓,使其在a<0.2时为艾里光束,而当a逐渐增大到0.7时,光波的外形轮廓已和高斯光束无异。

Abstract:

Based on light transfer matrix and Collins integral equation, the evolution of Airy Gaussian beam intensity side view in double negative material (DNM) with and without loss was discussed. Results show that the renewed original Airy Gaussian beam can be achieved perfectly by using lossless slab system contained negative index material as long as the negative refractive index nl=-nr and DNM unit length equals to the sum of two RHM units length on both sides of DNM unit; while nl≠-nr, the larger abs(nl) is, the longer DNM is needed to achieve beam reconstruction,and vice versa. As to losses situation, the smaller collision factors are, the better output Airy Gaussian beam quality is formed. It is further explored the propagation properties of Airy Gaussian beam changed with ζ factor and exponential truncation factor a, it is found that the beam self-bend is more obvious, and main lobe and side lobes are multiple decreased with the smaller ζ, even though the intrinsic nature of Airy Gaussian beam can not be affected by ζ factor. The exponential truncation factor a can control Airy Gaussian beam’s outline that likes an Airy beam when a＜0.2, but transforms into Gaussian beam profile while a=0.7.