We report on precise two-photon ablation with 110fs laser pulses at 1278nm, emitted from a Cr:forsterite laser. Selective two-photon ablation of Muntjac deer chromosomes is demonstrated. The two-photon absorption at 639nm was enhanced by using Methylene blue dye as a photosensitizer. This stain has a strong absorption in the region around 650nm but 100% transmission around 1300nm, allowing increased specificity: material that has absorbed the dye is ablated but undyed material is left unaffected. The low group velocity dispersion in glass at 1278nm led to negligible pulse broadening in the focusing objective where the 100fs pulses stretched to 110fs. This contrasts to the 100fs pulses at 780nm that were measured to stretch to 300fs under the same conditions.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics