Frequency-resolved measurement of the orbital angular momentum spectrum of femtosecond ultra-broadband optical-vortex pulses based on field reconstruction

作者：Keisaku Yamane, Zhili Yang, Yasunori Toda, Ryuji Morita · 发表于：New Journal of Physics · 年份：2014 · DOI：10.1088/1367-2630/16/5/053020 · 被引用次数：34 · 研究领域：Orbital Angular Momentum in Optics、Laser-Matter Interactions and Applications、Optical Polarization and Ellipsometry

We propose a high-precision method for measuring the orbital angular momentum (OAM) spectrum of ultra-broadband optical-vortex (OV) pulses from fork-like interferograms between OV pulses and a reference plane-wave pulse.It is based on spatial reconstruction of the electric fields of the pulses to be measured from the frequency-resolved interference pattern.Our method is demonstrated experimentally by obtaining the OAM spectra for different spectral components of the OV pulses, enabling us to characterize the frequency dispersion of the topological charge of the OAM spectrum by a simple experimental setup.Retrieval is carried out in quasi-real time, allowing us to investigate OAM spectra dynamically.Furthermore, we determine the relative phases (including the sign) of the topological-charge-resolved electric-field amplitudes, which are significant for evaluating OVs or OV pulses with arbitrarily superposed modes.