球形银纳米颗粒去极化光谱特性的理论研究

Theoretical study of depolarization spectral characteristics of silver nanoparticles

对球形银纳米颗粒在均匀散射场中的去极化行为进行了研究,测量了其去极化光学吸收光谱.结果表明,去极化场的相对透射光强度会随着粒子尺寸的增加而红移,也会随着外部介质的改变,即介电常数的增加而红移,并且粒子尺寸越大,外部介质介电常数越大,相对透射光强度也越大.这是由于去极化场的存在改变了金属表面等离子体共振的情况.

The depolarization behavior of spherical silver nanoparticles in a uniform scattering field is studied, and its depolarization optical absorption spectrum is measured.The spectrum shows that the depolarization field of relative intensity of transmitted light will red shift with the increase of particle size,and with the increase of dielectric constant surround the particle.The large of the particle size and the dielectric constant,the greater of the relative intensity of transmitted light.This is due to the existence of the depolarization field,which changes the surface plasmon resonance of metal.