Emission enhancement of femtosecond-laser-excited voxels using adaptive pulse shaping for volumetric display

Laser-excited volumetric displays render 3D volumetric images by focusing ultrashort laser pulses, whose intense electric fields ionize molecules to generate emission voxels. The image visibility and scale depend on the efficiency of laser excitation. However, generating emission voxels, particularly in the air, requires high pulse energy, making it essential to develop efficient voxel generation techniques to achieve images that can be experienced by users under typical lighting conditions. In this study, we propose a method using an optical pulse shaping system to adjust the temporal profile of femtosecond laser pulses for efficient voxel generation. A genetic algorithm was used to optimize the phase modulation pattern applied to the spatial light modulator, thereby exploring the optimal pulse shape to enhance voxel emission. As a result, a 1.82-fold enhancement in the emission intensity was achieved compared to the unshaped pulse condition.