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We investigated a simple and productive micromachining method of silica glass by ablation using a TEA CO laser (10.6 μm) with a spatial resolution down to sub-wavelength scale. The silica glass was irradiated by the TEA CO laser light through a copper grid mask with square apertures of 20×20 μm attached to the silica glass surface. After the irradiation, circular holes with a diameter of several μm were formed on the silica glass surface at the centers of the apertures due to the Fresnel diffraction effect. The minimum diameter of the holes was 3.4 μm. The characteristics of the micromachining are discussed based on the electric field distributions of the CO laser light under the mask using a three-dimensional full-wave electromagnetic field simulation. [ABSTRACT FROM AUTHOR]

The laser-induced back-side wet etching of fused silica with aqueous solutions of pyranine (8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt) is reported. KrF and XeF excimer lasers were employed as light sources. Well-defined line-and-space and grid micropatterns, free of debris and microcracks, were obtained. Compared with other organic solutions, the aqueous pyranine etching medium etches more slowly but produces a higher quality etched surface. With the KrF laser, the etch rate ranged from 0.02 to 0.12 nm pulse[sup -1] , depending on the dye concentration and the fluence of the laser. The etch rate decreased dramatically when the XeF laser was employed, which was partially attributed to the lower absorption efficiency of the aqueous pyranine solution at the XeF laser wavelength. [ABSTRACT FROM AUTHOR]

Abstract. We have developed a one-step technique to fabricate a well-defined pattern of lines and spaces in fused silica with micro-sized features, using laser-induced backside wet etching (LIBWE). The etch rate ranged from 5 to 25 nm/pulse with KrF laser irradiation from 400 to 1300mJ/cm[sup 2] and an acetone solution containing pyrene at a concentration of 0.4 mol/dm[sup 3]. The threshold fluence was 240 mJ/cm[sup 2], which is about one-fortieth lower than that obtained with conventional KrF laser ablation. [ABSTRACT FROM AUTHOR]

Abstract. We fabricated a well-defined pattern of lines and spaces on the surface of a quartz crystal plate (c-SiO[sub 2]) with micron-sized features, using laser-induced backside wet etching (LIBWE). The line patterns obtained using LIBWE showed a high aspect ratio of about 3. The etch rates of fused silica (a-SiO[sub 2]) ranged from 5 to 25 nm/pulse with KrF laser irradiation from 0.4-1.3 J/cm[sup 2]. Threshold fluences for a-SiO[sub 2] and c-SiO[sub 2] were 0.23 and 0.34J/cm[sup 2], respectively. The single-pulse etch depth was not affected by the repetition rates of laser pulses from 1-50 Hz. [ABSTRACT FROM AUTHOR]