Spatial limit of two-beam interference patterning with ultrashort laser pulses

Two-beam interference patterns generated with ultrashort laser pulses are essential for applications such as direct laser interference patterning. Here, coherent beams are made to interfere by overlapping on the processed surface. The area of the generated interference pattern can be adjusted by the transverse beam dimensions. The present study investigates the spatial limit of interference patterns. The results demonstrate that the boundaries of the interference pattern depend solely on the spectral energy distribution of the laser pulse, and the angle between the interfering beams. The variation in pulse duration, which arises in the non-bandwidth-limited case while maintaining the same spectral energy distribution, has no effect.