Sub-diffraction limited structuring of solid targets with femtosecond laser pulses

Abstract

Possibilities to produce sub-diffraction limited structures in thin metal films and bulk dielectric materials using femtosecond laser pulses are investigated. The physics of ultrashort pulse laser ablation of solids is outlined. Results on the fabrication of sub-micrometer structures in 100-200 nm chrome-coated surfaces by direct ablative writing are reported. Polarization maintaining optical waveguides produced by femtosecond laser pulses inside crystalline quartz are demonstrated.

Spectral broadening in femtosecond laser written waveguides in chalcogenide glass

“…When viewed in units of absorbance it is clearer to see that the band edge of GLS lies at around 500 nm [25]; however, units of transmission make the band edge shifts more apparent. Other authors have suggested a color-center model to explain index modification in glasses after fs-laser exposure [3,23,26]. This model stipulates that fs-laser pulses introduce color centers in sufficient numbers and strength to alter the index through a Kramers-Kronig mechanism.…”

“…These include the reduction of collateral damage [1] and the ability to achieve subdiffraction limited ablation [2][3][4]. In gold films, 800 nm fs lasers have been used to ablate holes roughly 10% of the focus spot size [5].…”

Influences of the Filter Effect on Pulse Splitting in Passively Mode-Locked Fiber Laser with Positive Dispersion Cavity

“…High-repetition-rate and large energy ultra-short laser pulses are very important for applications of nonlinear frequency conversion, ultrafast dynamics exploration, and optical precision procession [1][2][3]. Rare-earth doped silica-based fibers are very good gain media for building mode-locked lasers generating such ultra-short pulses [4][5][6][7][8].…”

Femtosecond laser ablation of metals and crater formation by phase explosion in the high-fluence regime

“…Accordingly, several models were proposed for numerical simulation of the fs ablation of metals [2][3][4]. However, predicting the topography generated by femtosecond (fs) laser pulses is a challenging task since there are many ambiguities as to the physical mechanisms of material ablation and most of the previously suggested numerical models are one-dimensional for simplicity of computation.…”

“…In this work, a twodimensional computational model is presented for theoretically predicting the femtosecond laser ablation and crater formation. The model is based on the two-temperature description of the nonequilibrium state [2] and material removal by phase explosion. Accordingly, the model is effective for predicting relatively high-power ablation of metals.…”