The existence of Majorana fermions in hybrid semiconductor/superconductor heterostructures was studied, and an all-optical method to probe the Majorana fermions by using coherent optical spectra was presented. A strong pump laser and a weak probe laser were acted on semiconductor quantum dot, and the coherent optical spectra were derived by the Hamiltonian of system. The numerical results indicate that the coherent optical spectra present a distinct signature of the coupling between the semiconductor quantum dot and the Majorana fermions in the optical detection method. The characteristic of non-contact between the semiconductor quantum dot and the Majorana fermions can make the detection process avoid introducing noises. The coupling strength between the semiconductor quantum dot and the Majorana fermions is proportional to the distance of two the peaks in the probe absorption spectrum, so that the coupling strength can be obtained by measuring the distance of two the peaks, which presents a straight forward means to determine the coupling strength.MOURIK V, ZUO K, FROLOV S M, et al. Signatures of Majorana fermions in hybrid superconductor-semiconductor nanowire devices［J］. Science, 2012, 336(6084): 1003-1007.