THE STUDY ABOUT RELATIONSHIP BETWEEN CO-APERTURE SPLITTING RATIOS AND LASER FAR-FIELD SPOT MORPHOLOGY AND POWER

Abstract

To address the problem of difficult to determine the beam splitting ratio of the spectroscopic system which results from the overlapping optical paths for laser emission and imaging in laser countermeasure shared aperture system, this paper conducts a field experiment which investigates the relationship between laser spot size control and the far-field spot morphology and the energy density magnitude at the central spot using the 3.7𝝁𝒎 mid-wave infrared laser band as the light source. After setting up the field test conditions the laser pattern and energy in the far field is measured steadily by changing the stop size at the front of the laser near the conventional 86.5% laser energy. By analysis in the case of 30% to 70% laser energy outer ring blocking light, the maximum change in spot size is 1/3, the energy in the centre of the spot is affected considerably, in a non-linear relationship, especially after the blocking of light in more than 30% energy drops sharply.