吸收率可控上转换纳米颗粒对激光的吸收与散射

The research on the multiply diffraction and absorption of the laser in the transmission of the atmosphere was blocked due to the lack of stable experimental model. Here, we try to build a 3D space model of particles distribution based on upconversion nanoparticles with controllable size and absorptivity, to simulate the the multiply diffraction and absorption of the laser in the transmission of the atmosphere, which is valuable to reveal the decay mechanism and deviation of wave facets of the transmission laser in the atmosphere. The normal distribution function was introduced into the Fraunhofer approximation to describe the particle size and absorptivity differences among particles for optimizing the deviation between theoratical simulation and practical results. to pre-caculate the experimetnal model by Fraunhoder approximation which is compared to the expertimental data for optimizing the theoretical model. To verify the Fraunhofer approximation model containing the normal distribution function by the experimental data and in the practical atmosphere environment. The results present theoretical support for revealing the absorption and scattering mechanisms of laser by the particles in the atmosphere and to enhance the precision of not only the laser communication but also the laser counting of particles.

由于缺乏稳定可靠的实验模型，激光在大气中传输时发生的多重光散射与吸收机制的理论模拟研究受到了限制。本项目拟基于尺寸和吸收率可控上转换纳米颗粒构建颗粒三维空间分布模型，模拟大气中颗粒物对激光的吸收与散射，对于深入揭示大气通道对激光的衰减机制及产生的波形畸变具有重要的理论价值。在原有Fraunhofer-近似模型中引入正态分布函数描述各种颗粒的尺寸和吸收率差异，使模型条件更接近实际情况。通过含正态分布函数的Fraunhofer-近似模型对实验模型进行预计算，并与实验测试结果对比，利用实验结果修正理论模型。利用含正态分布函数的Fraunhofer-近似模型模拟实际大气中颗粒对激光的吸收与散射，验证其实际可行性及精确度。本项目的研究成果可望为揭示大气中颗粒物对激光的吸收与散射机制，并由此提高激光通信和激光粒子计数的精度提供理论依据。

激光在介质中传输时发生的多重光散射与吸收机制的研究由于受实验条件的限制，且存在多重非理想因素的干扰，理论模拟与实验结果往往难以精确匹配。本项目基于尺寸和吸收率可控上转换纳米颗粒构建颗粒三维空间分布模型，揭示了纳米颗粒对激光吸收与散射过程中的一些重要规律，具有较重要的科学价值。利用外加磁场会导致发光中心离子的能级发生分裂，以致于亚能级上的电子数显著减少，从而引起荧光效率的降低这一原理，探索了上转换纳米颗粒对980nm红外激光的吸收、散射。利用上转换纳米颗粒本身的荧光特性标定吸收与散射效率；利用磁场调控上转换纳米颗粒对980nm红外激光的吸收与散射比，从而揭示纳米颗粒尺寸、折射率、介电常数等关键因素对红外激光的吸收与散射规律，并与FDTD模拟结果对比，获得了有价值的研究成果，构建了折射率（或介电常数）对光的吸收与散射的重要规律，并观测到了纳米尺度非金属光限制现象。此外，发现利用表面等离子体产生的能量波可以补偿能级分裂引起的能量失配，从而抵消磁场对上转换发光过程的影响。探索了无机纳米颗粒与有机分子之间共振能量传递的有效距离，研究无机纳米颗粒在有机分子共存条件下的光子吸收与能量交换机制。该项目的研究成果对于揭示其它类型纳米颗粒（比如金属纳米颗粒、半导体纳米颗粒）对激光的吸收与散射规律及机制具有较重要的指导价值；同时该项目的研究成果在超灵敏光学传感器、红外探测、磁光效应传感器等领域有相当好的应用前景，对于推动相关领域的基础理论研究的进步和产业化发展具有一定的参考价值。

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