泵浦光激发下金刚石纳米柱内部光场的研究

金刚石纳米柱是实现色心单光子源增强的有效结构,而纳米柱结构尺寸决定泵浦光对色心的激发强度.本文为提高其激发效率,采用时域有限差分法(Finite Difference Time Domain, FDTD)研究金刚石纳米柱的光学性质.通过仿真分析了纳米柱直径和高度对内部电场强度的影响.结果表明,在泵浦光波长为532 nm时,纳米柱内部中轴线上场强受尺寸变化影响较大,当直径不变、改变高度时,场强最大值随高度周期性变化,周期约为150 nm;当高度不变、改变直径时,场强最大值也随直径周期性变化,周期约为150 nm.通过研究不同波长的泵浦光对金刚石纳米柱内部中轴线上电场分布的影响发现,不同波长的泵浦光对纳米柱内部中轴线上最强场强对应的纳米柱尺寸有较大影响,但对于纳米柱最大场强随纳米柱尺寸变化的趋势几乎没有影响.本文通过研究上述内容,较为全面地掌握了纳米柱尺寸及泵浦光对纳米柱内部电场强度的影响规律,找到了纳米柱内部中轴线上最强场强位置,确定了激发色心的效率最高值所在位置,为金刚石纳米柱单光子源的制备提供理论指导.

Study on the Internal Light Field of Diamond Nanocolumns Excited by Pumped Light

Diamond nanocolumns are effective structures for color center single photon source enhancement, and the size of the nanocolumns determines the excitation intensity of the pumped light to the color center. In order to improve the excitation efficiency, the optical properties of diamond nanocolumns were studied by Finite Difference Time Domain (FDTD) method. The effect of diameter and height on the internal electric field intensity was analyzed by simulation. The results show that when the wavelength of pumping light is 532 nm, the field intensity of the inner axis of the nanometer column is greatly affected by the size change. The maximum field intensity changes periodically with the diameter or the height, in a magnitude of 150 nm. Focusing on the electric field distribution on the inner axis of diamond nanocolumns, it is found that the pump light with various wavelengths has a significant influence on the size of the nanocolumns. However, the influence can be minimal with regard to the trend of the maximum field intensity. This paper thoroughly investigated the influence of the nanocolumns'' size as well as pump light on the internal electric field intensity. It also found the position where the internal field strength and the efficiency of the excitation color center reach the peak. This would provide sufficient theoretical guidance for the preparation of nanometer column single photon source in the future.