Micromachining of transparent materials with super-heated liquid generated by multiphotonic absorption of organic molecule

Micromachining of transparent materials with a well-defined pattern of lines and spaces was carried out by laser-induced backside wet etching LIBWE.. The etch rate of a fused silica plate ranged from 5 to 25 nmrpulse with a KrF laser irradiation from 400 to 1300 mJrcm2, using an acetone solution containing pyrene at a concentration of 0.4 molrdm3. Threshold fluences for etching of fused silica and calcium fluoride plates were 240 and 740 mJrcm2, respectively, which are remarkably lower than those with conventional KrF laser ablation. The mechanism for etching is explained by the attack of super-heated molecules generated by laser ablation of a pyrene–acetone solution during cyclic multiphotonic absorption. q2000 Elsevier Science B.V. All rights reserved