An original in-situ experimental approach is proposed to estimate the absorption function of soot particles in flames: the two Separated Pulses Laser-Induced Incandescence technique (SP-LII). The SP-LII technique is based on measuring the peak temperature of soot particles heated by laser pulses at two different fluences. From these two temperature measurements, the absorption function is estimated by solving the energy equation applied to soot particles during laser energy absorption once the product of soot density and specific heat is known. In order to solve the energy equation, two methods are considered here. The first method, called the "absorption model" (AM), solves the energy equation when all loss terms are neglected during absorption. The second method uses a look-up table (LUT) generated with an LII code in which the main loss terms are modelled. Both methods also provide information on the gas temperature T 0 , assuming that gas and solid phases are at equilibrium. First, the SP-LII technique's accuracy and limits are theoretically explored using peak temperatures from simulations done with an LII code. Overall, the AM method is efficient but is restricted to soot primary particles diameter >∼ 10 nm and low fluences. By contrast, the LUT method has an extended operational range, but it requires more information than the AM method, and its accuracy depends on the validity of the power loss models used to generate the look-up table. It is then concluded that the AM method represents the best compromise between the complexity of the methods and the expected accuracy of the results. Then, the feasibility of the SP-LII technique is proven by performing measurements in a laminar diffusion methane/air sooting flame and post-processing them with the AM method. Results for the absolute value and for the spatial evolution of E(m λ) are coherent with the literature. Finally, a possible extension of the SP-LII technique to turbulent flames is discussed.