激光自混频技术可用于纳米颗粒和纳米流体的探测。在纳米流体自混频信号自相关函数的基础上,理论推导了功率谱函数的表达式。结果表明,纳米流体的激光自混频信号功率谱是洛伦兹线型和高斯线型的卷积,即佛赫特(Voigt)线型。通过数值计算研究了各种典型情况下激光自混频信号功率谱的频谱特征,颗粒定向运动速度决定了多普勒频移和高斯线宽,颗粒粒度决定了洛伦兹线型的宽度,颗粒粒度和速度与功率谱之间的对应关系为纳米流体的测量提供了理论基础。 Laser self-mixing technology can be used for the detection of nanoparticles and nanofluids. Based on the autocorrelation function of nanofluid self-mixing signal, the expression of power spectrum function is derived theoretically. The results show that the laser self-mixing signal power spectrum of nanofluids is a Lorentz-Gaussian line type convolution, ie Voigt line type. The spectral characteristics of the laser self-mixing signal power spectrum under various typical conditions are studied numerically. The directional velocity of particle determines the Doppler shift and the Gaussian linewidth. The particle size determines the width of the Lorentz line, The correspondence between particle size and velocity and power spectrum provides a theoretical basis for the measurement of nanofluids.