Mode spectrum of misaligned Hermite Gaussian beam
We analyze the mode spectrum of a Hermite-Gaussian (HG) beam projected with lateral misalignment from the principal axis. Due to the misalignment of the beam, the weight of information in the mode spectrum of the corresponding projection is distributed to different mode orders. This will lead to loss of retrieved information, specifically for applications in optical communication and image reconstruction, since the methods only capture few mode orders. We then present a method to determine the mode orders where the weight of information loss are distributed by analyzing the mode spectrum of the misaligned beam. We utilize the method of mode projection of different misaligned beams to construct a mode spectrum for analysis. By inspecting the mode spectrum and locating the significant mode orders, this will pave the way to retrieve the lost information due to the misalignment.