Research On Laser Radar Linear Array Illumination Based On Darman Grating

Linear array scanning imaging laser radar is the key sensor of autonomous vehicle and its important development directions are miniaturization,low power consumption and low cost under the premise of ensuring the detection performance. In this paper, the design of the optical system of linear array laser radar is introduced, which is based on the principle of Dammann grating. The aim is to improve the illumination efficiency and beam splitting uniformity of the laser radar emission lighting system and to offer a new approach to the miniaturization and low power design of the vehicle borne laser radar.On the basis of thorough investigation and research, this paper completes the overall structure of the line array lighting system of Dammann grating laser radar and discusses the requirement of the components. The numerical calculation and analysis of the principle of the Dammann grating and the beam splitting are discussed.Then,the relationship between the intensity distribution of the light beam and the incident light intensity distribution of the Dammann grating array is presented. On this basis,this paper designs a Dammann grating which wavelength is 1.06μm and the splitting ratio is 13 by hybrid optimization algorithm. Its diffraction efficiency is more than 80%, and the uniformity is less than 15% through calculation and evaluation of beam splitting performance in diffraction theory. In the experiment, the Chengdu photoelectric Institute of the Chinese Academy of Sciences has made one dimensional Dammann grating which wavelength is 1.06μm and the splitting ratio is 13. In the paper,a laser radar array illumination experiment device based on one dimensional Dammann grating is built. Results show that the linear array laser radar array by the combination of the Dammann grating and the Kepler inverted telescope is an effective scheme for the illumination design based on contrast experiments of 532nm,905nm and 1.06μm wavelength. The overall diffraction efficiency of the optical system is close to 70%, and the non-uniformity of the illumination beam is less than 20%　on the wavelength of 1.06μm. The whole optical system is still the diffraction efficiency is higher than 65%, in addition to the 0 level illumination light beam between the non-uniformity of less than 20%　when the wavelength is off to 905nm.The research work in this paper has a certain reference value for the miniaturization and low power design of the vehicle linear array scanning imaging laser radar array.