Microstructuring using Short-Pulse Lasers

Photonic glass devices can be produced by femtosecond lasers exposure [228]. To produce such devices ablation should be avoided but photochemical effects are desired to modify the refractive index. Femtosecond laser 

the change of valency of dopants, e.g. Ag+ in doped glasses, and also the generation of optical images are described by Shimotsuma et al. [464]. They used a pulsed femtosecond Ti Sapphire laser and different silicate and tellurite glass. 

The photo-induced microcrystallisation in photosensitive glasses was also investigated [304]. The crystallisation is induced by multi-photon absorption of a fs-laser beam operating in the non-resonant wavelength range. 

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Another technological breakthrough in optical hber technology, however, allows one to upgrade established 100 fs-class laser systems for broadband applications and even surpass the bandwidth of dedicated short-pulse Ti sapphire lasers. Key to this is the use of novel microstructured optical hbers, which are designed to exhibit extremely high optical nonlinearities. If nanojoule femtosecond laser pulses are launched into such a hber, the combination of different nonlinear optical processes leads to the creation of new frequency components. Therefore, the laser bandwidth can be increased dramatically by orders of magnitude. 

Consequently such a microvaporizer uses a glass-silicon-glass stack with a microstructured silicon evaporator. This evaporator is heated up by a pulsed NIR-laser diode. Thus, the liquids which are in contact with the evaporator within a very short period of time are heated beyond their evaporation temperature. This arrangement not only requires a low energy to evaporate in comparison to the commonly used resistive heating, but the very rapid heating of the silicon vaporizer also allows for simultaneous evaporation of sample mixtures with components of different evaporation temperatures and partial pressures, respectively. Furthermore,... 

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