Liu Houquan, Teng Chuanxin, Yang Hongyan, Deng Hongchang, Xu Ronghui, Deng Shijie, Chen Ming, Yuan Libo
Opt Express. 2018 May 28;26(11):14792-14799. doi: 10.1364/OE.26.014792.
In this letter, a quadratic phase plate (QPP) whose thickness increases quadratically with azimuthal angle φ is proposed. When a beam with initial topological charge m (m could be an arbitrary integer) is passed through the plate, quadratic phase modulation can be expected to expand the initial single orbital angular momentum (OAM) mode to a superimposed OAM state. The obtained multi-OAM state exhibits a comb-like OAM spectrum, which shows a flat region. The power variation of the OAM modes within the flat region is less than 3 dB, while the power for the OAM modes with charge numbers out of the flat region decays rapidly. Moreover, the number of OAM modes within the flat region can reach dozens. This may have potential applications in the field of communication, quantum information and optical manipulation, etc.
在这封信中，提出了一种厚度随方位角φ呈二次方增加的二次相位板（QPP）。当具有初始拓扑电荷m（m可以是任意整数）的光束穿过该板时，预计二次相位调制可将初始的单轨道角动量（OAM）模式扩展为叠加的OAM状态。所获得的多OAM状态呈现出梳状的OAM光谱，该光谱显示出一个平坦区域。平坦区域内OAM模式的功率变化小于3 dB，而电荷数超出平坦区域的OAM模式的功率则迅速衰减。此外，平坦区域内的OAM模式数量可以达到数十个。这可能在通信、量子信息和光学操控等领域具有潜在应用。
