Dynamics of low-threshold random laser based on TiO2 nanoparticle films
-
摘要: 本文利用共轭聚合物(MEH-PPV)覆盖TiO2纳米粒子薄膜制作随机激光器。随机TiO2纳米粒子薄膜的激光辐射阈值比平面MEH-PPV薄膜的放大自发辐射阈值缩小了9倍。这是由于TiO2纳米粒子诱导的多重散射造成的。进一步的飞秒荧光上转换实验表明,随机激光器中,光在增益介质里的停留时间有所增加,这直接证实了光在随机激光器结构中的多重散射引起光的传播路径增加。因此,这会促进更多的光发生辐射,从而降低随机激光器的阈值。Abstract: We have prepared random lasers with conjugated polymer(MEH-PPV) coated on TiO2 nanoparticle films. The threshold of the lasing based on random TiO2 nanoparticle film is significantly reduced by a factor of 9 in comparison with the amplified spontaneous emission(ASE) threshold of the flat MEH-PPV film, which is caused by multiple scattering induced by TiO2 nanoparticles. Further investigation by femtosecond fluorescence up-conversion experiment reveals that the dwell time of light inside the gain medium is increased in the random laser device, which directly confirms that light travels longer path due to the multiple scattering in the random structure. So it stimulates the emission of more light and the threshold of the random laser is lowered.
-
图 1 (a)随机激光器结构图；(b)TiO2纳米粒子薄膜原子力显微镜图像
Figure 1. (a)Schematic of the fabricated random laser; (b)AFM image of TiO2 nanoparticle film
图 2 在不同泵浦光强度下的发射光谱
Figure 2. Measured spectra of the output emission at different pump intensities of MEH-PPV on (a)FTO and (b)TiO2 nanoparticle film
图 3 发射光强度和随泵浦光强度的变化
Figure 3. Output intensity and FWHM as a function of the pump intensities
图 4 610 nm出射光的动力学随不同激发光强度的变化
Figure 4. Emission dynamics of 610 nm under varies excitation intensities of MEH-PPV on (a)TiO2 nanoparticle film and (b)flat FTO
-
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] -
下载:
计量
- 文章访问数: 1995
- HTML全文浏览量: 683
- PDF下载量: 687
- 被引次数: 0
