Multiwavelength ghost imaging

In this paper, we analyze the multiwavelength thermal ghost imaging with the spatial light modulating system (SLMS) and rotating ground glass plate (RGGP), respectively. We find that the multiwavelength ghost imaging dramatically enhances the signal-to-noise ratio (SNR) of ghost imaging for all types of objects. The $N$-wavelength ghost imaging with SLMS produces ${N}^{2}$ ghost images incoherently added together to form one ghost image whose SNR is ${N}^{2}$ times the one of single-wavelength ghost imaging. The $N$-wavelength ghost imaging with RGGP produces $N$ ghost images incoherently added together to form one ghost image whose SNR is $N$ times the one of single-wavelength ghost imaging. We find that a quantum effect is involved in the thermal light, although in a specific scenario at present. Moreover, the color ghost image obtained by the multiwavelength ghost imaging is better than the monochromatic ghost image in our observation.