基于带通滤波片的激光二极管自混频纳米颗粒干涉测量技术

激光二极管自混频技术可用于纳米颗粒的测量,采用多通道带通滤波技术分别测量了180,100,60nm三种纳米颗粒,获得自混频信号的频带功率谱(PS-BPF)。作为比较,对实时提取的自混频信号进行傅里叶变换得到功率谱密度(PSD)函数。分别对PSD函数和PS-BPF反演计算得到颗粒粒径分布。结果显示:两种方法得到的颗粒粒径分布基本一致,并与商用仪器测试结果吻合。对两种处理方式的模式矩阵分析表明,多通道带通滤波技术明显优于PSD函数处理方式。

Measurement Technique on Nanoparticles with Laser-Diode Self-Mixing Interferometry Based on Bandpass Filters

The laser-diode self-mixing interferometry can be employed to measure the sizes of nanoparticles. The standard nanoparticles whose sizes are labeled as 180, 100 and 60 nm are measured and the corresponding power spectra of the self-mixing signals are obtained with a series of bandpass filters. As a comparison, the power spectral densities (PSD) are achieved from the Fourier transform of the self-mixing signals which are recorded in real time. With the inversion algorithm, the particle-size distributions are extracted from either the PSD or the power spectra with bandpass filters (PS-BPF). It is showed that the particle-size distributions obtained from these two methods agree with each other and consist satisfactorily with those measured by the commercial particle-size analyzer. The analysis on the illness condition of modal matrices of these methods indicates that the technique based on bandpass filters is better than that based on the PSD.