Mohagheghian Maryam, Ghavami Sabouri Saeed
Opt Express. 2022 Mar 14;30(6):9494-9504. doi: 10.1364/OE.453618.
We propose the use of an intensity technique to decompose superpositions consisting of two, three, or four basis Laguerre-Gaussian (LG) modes, and measure the orbital angular momentum (OAM) of such superpositions. The mode generation and decomposition are both accomplished only on a 2f optical imaging system. We demonstrate numerically and experimentally that the squared amplitudes of superpositions can be determined by recording a single frame of the intensity distribution. This is accomplished by measuring the intensity along certain circles and solving a linear set of equations relating the sampled intensities to squared amplitudes. The accuracy of better than 98% for composite beams consisting of two, and about 90% for composite beams consisting of more than two basis modes are achieved. Finally, we report the value of the measured OAM of the superpositions with excellent accuracy regarding theoretical values, for small and large integer and non-integer OAM.
我们提出使用一种强度技术来分解由两个、三个或四个基拉盖尔 - 高斯（LG）模式组成的叠加态，并测量此类叠加态的轨道角动量（OAM）。模式生成和分解仅在一个2f光学成像系统上完成。我们通过数值和实验证明，叠加态的平方振幅可以通过记录强度分布的单帧来确定。这是通过沿着某些圆周测量强度并求解一组将采样强度与平方振幅相关联的线性方程组来实现的。对于由两个基模式组成的复合光束，精度优于98%；对于由两个以上基模式组成的复合光束，精度约为90%。最后，我们报告了对于小整数、大整数和非整数OAM叠加态，测量得到的OAM值与理论值相比具有极高的精度。
