UV photoablation of materials is recorded for both the near and far fields after transmission through a Dammann grating. The fused silica Fourier lens used for far-field imaging was damaged by a near-field intensity pattern with the same periodicity as the Dammann grating. The lens was located inadvertently at one eighth of the Talbot distance Z T behind the Dammann grating. Patterns recorded in copper film at the even-fractional Talbot planes compare qualitatively with calculated intensities. On the basis of these findings, a near-field intensity pattern was used to ablate vias in copper and polyimide films. The pattern at a distance of ZT/8 was used for via ablation because it is the pattern with the most fluence per spot.
© 1997 Optical Society of America
Karim Tatah, Akira Fukumoto, Thomas J. Suleski, and Donald C. O’Shea, "Photoablation and lens damage from fractional Talbot images of Dammann gratings," Appl. Opt. 36, 3577-3580 (1997)