Numerical simulations on the formation of speckles when illuminating nanofluids with laser

A computational model is established to do the numerical simulations on the formation of speckles when nanofluids are illuminated by laser. The intensities of 121 points that are evenly distributed on a 1 cm × 1 cm square area in the center of the screen are calculated by incoherent addition of the amplitudes and coherent addition of the complex amplitudes of the scattering lights from multiple nanoparticles. Numerical results show that speckles can not be formed by incoherent addition of amplitudes of the scattering lights from multiple nanoparticles. However, the speckle pattern that consists of few bright speckles and much dark speckles can be formed by coherent addition of the scattering lights from multiple nanoparticles.