Izadi Mohammad Amin, Nouroozi Rahman
Department of Physics, Institute for Advanced Studies in Basic Sciences, Zanjan, 45137-66731, Iran.
Sci Rep. 2018 Oct 19;8(1):15495. doi: 10.1038/s41598-018-33831-y.
The adjustable propagation length enhancement of the surface plasmon polariton (SPP) mode under the effects of the initial relative phase (ψ) between interacting waves in difference frequency generation (DFG) based optical parametric amplification (OPA) are numerically considered. The waveguide is a silver coated PPLN planar waveguide. Obtained results indicate ultra long propagation length for the SPP mode could be achieved via manipulation of ψ in exact quasi phase matching (QPM) case up to 30 mm for initial pump intensity about 66 MW/cm for degenerate DFG (dDFG). For chirped QPM by mitigating the high depletion of the pump intensity, it is possible to enhance the SPP propagation length up to 43 mm for initial pump intensity about 135 MW/cm. In this case ψ does not affect the SPP propagation length except around a narrow range of unsuitable phases. The unsuitable phase is [Formula: see text] for exact QPM but is pump dependent for chirped QPM case. Using this unsuitable phase is the key parameter to the SPP propagation length enhancement via controlling ψ. In this case with a high pump intensity, the pump and the SPP modes interact at longer distances which leads to the SPP propagation length enhancement.
数值研究了基于差频产生（DFG）的光学参量放大（OPA）中，相互作用波之间的初始相对相位（ψ）对表面等离激元极化激元（SPP）模式可调传播长度增强的影响。该波导是镀银的周期极化铌酸锂（PPLN）平面波导。所得结果表明，在精确准相位匹配（QPM）情况下，通过控制ψ，对于简并DFG（dDFG），当初始泵浦强度约为66 MW/cm²时，SPP模式的传播长度可达到30 mm。对于啁啾QPM，通过减轻泵浦强度的高损耗，当初始泵浦强度约为135 MW/cm²时，有可能将SPP传播长度提高到43 mm。在这种情况下，除了在一个狭窄的不合适相位范围内，ψ不影响SPP传播长度。对于精确QPM，不合适相位为[公式：见原文]，但对于啁啾QPM情况，它与泵浦有关。利用这个不合适相位是通过控制ψ增强SPP传播长度的关键参数。在这种高泵浦强度情况下，泵浦和SPP模式在更长距离上相互作用，这导致了SPP传播长度的增强。
