【摘要】 针对"正折射率(PIM)/负折射率(NIM)/正折射率(PIM)"结构的材料,研究了对信号光是负折射率而抽运光和闲频光都是正折射率时,在三波非共线参变放大的基础上,根据匹配条件,对于给定的信号光和抽运光波长,非共线角α存在最大值即最大非共线角,并详细研究了最大非共线角随信号光波长的变化规律。利用泰勒级数将波矢按圆频率展开,在取一级近似的情况下,得到了带宽的解析表达式。利用该解析式,采用数值计算的方法,分别研究了带宽随信号光波长、抽运光波长和非共线角的变化规律。结果表明,对于同一抽运光,随着信号光波长的增加,参变带宽将先增加而后减小,即参变带宽存在着最大值;随着抽运光波长的减小,参变带宽将增大;对于同一信号光和抽运光,随着非共线角α的增大,参变带宽Δλ将逐渐增大。此外,随着抽运光强的增大,带宽也将增大。这为实验研究负折射率材料的光参变放大打下了基础。更多还原

【Abstract】 In negative-index materials(NIM) for signal wave and positive-index materials(PIM) for pump wave and idler wave in the structure of PIM/ NIM/PIM,based on three-wave mixing optical parametric amplification,according to the phase matching,there is a maximum noncollinear angle(MNA) when these wavelengths of signal wave and pumping wave are given.The curve of the MNA vs the signal wavelength has been discussed in detail.A analytical expression of spectral bandwidth is obtained through retaining term of first order(when expanding circular frequence of wave vector in Taylor series).Making use of the analytical expression,one has researched this laws of the parametric bandwidth vs the wavelength of signal light,pump light and the noncollinear angle through the method of numerical calculation.Results show that the parametric bandwidth first increased and later diminished with increase of the signal wavelength for the fixed pump wavelength,that is,the maximum parametric bandwidth existed;the parametric bandwidth gradually increased with increase of the noncollinear angle for the fixed pump wavelength and signal wavelength.Besides,the parametric bandwidth also increased with increase of the pump-light intensity.This study provides a basis for investigating optical parametric amplification of negative-index materials.更多还原