【作者】 胡兵；

【导师】 侯延冰；

【作者基本信息】 北京交通大学 ， 光学工程， 2011， 硕士

【摘要】 有机激光器存在着很多潜在的优点：加工制造工艺简单,制造成本较低,激光波长可调,可以在基片上实现大面积集成等。而有机半导体共轭聚合物由于具有较高的荧光效率,较大的受激发射截面,是一种很好激光器的增益介质,所以近年来,有机半导体共轭聚合物材料成为有机光电材料领域主要的研究方向之一。本论文主要研究了波导结构的有机共轭聚合物材料MEH-PPV的薄膜的放大辐射特性及其影响因素。在实验中我们利用旋涂法制作了以甲苯为溶剂的MEH-PPV溶液的三层非对称波导结构的器件,在500 nm的激光泵浦的条件下观察到了MEH-PPV薄膜的受激发射。并且我们发现当泵浦光光强较低时,受激发射的光强也相对较低,谱线的半高宽也比较大,但是随着泵浦光光强的增强,发射光强出现较大的增长,显现出阈值的特性,并且发射谱线的半高宽也有明显的窄化。通过对比测量我们发现随着器件薄膜的厚度的增加器件的阈值有明显的下降,当薄膜厚度为93.3 nm时器件的阈值为0.219μJ/pluse,厚度增加至279.3 nm时,阈值下降至0.162μJ/pluse,而且此时器件的净增益达到28.2 cm-1。因为厚度的增加还有可能使泵浦能量快速耗尽,以及材料具有较高的衰减系数,所以器件薄膜的厚度也不能无限扩大。为了进一步认识厚度与受激发射的关系及规律,我们通过提高溶液的浓度和自然扩散法设计制作了560 nm和微米级别的器件进行研究。最后对于不同的溶剂在相同的浓度下对波导结构的MEH-PPV薄膜器件的受激发射进行了研究。发现符合最适宜成膜的条件的氯苯溶剂所制作的器件的性能最佳,经过分析认为此器件的薄膜最为平整,通过原子力显微镜也证明此溶剂制作的波导的粗糙度最小。更多还原

【Abstract】 The organic laser has many potential advantages:easy fabrication, low costs, tunable emission wavelength, large-scale integration. In recent years, conjugated organic semiconductor polymers have been one of the main research directions in organic optoelectronic materials due to their high fluorescence efficiency, large excitation cross section. In this paper, we discuss the amplified spontaneous emission (ASE) characteristics in MEH-PPV film and factors to influence ASE.Under the pump of 500nm pulse laser, ASE of the MEH-PPV waveguide with asymmetric structures was investigated. We found that the output intensity is lower and the full width at half maximum (FWHM) is wider when the pump intensity is lower. However, with the increasing pump intensity, the quick increase in output intensity y and the FWHM narrowing shows threshold characteristics. The threshold is 0.226μJ/pluse when the film is 93.3 nm and with the increase of film thickness the threshold drop to 0.16μJ/pluse, and the gain increase to 28.2 cm-1. However the thickness can not increase unlimitedly because of high attenuation coefficient and the pump energy can be used up rapidly. So we make the micron and 560 nm film to find the connection between stimulated emission and thickness.We also study ASE with similar MEH-PPV films spin-coated for different solvent. Compared with the other solvent, chlorobenzene is proper solvent because of it’s specifics such as:boiling points, surface tension etc. After the AFM measurement, I confirm that the chlorobenzene film has the most smoothly surface, so chlorobenzene film has the best threshold and gain.更多还原