An improved method for producing fiber tips for scanning near-field optical microscopy is presented. The improvement consists of chemically etching quartz optical fibers through their acrylate jacket. This new method is compared with the previous one in which bare fibers were etched. With the new process the meniscus formed by the acid along the fiber does not move during etching, leading to a much smoother surface of the tip cone. Subsequent metallization is thus improved, resulting in better coverage of the tip with an aluminum opaque layer. Our results show that leakage can be avoided along the cone, and light transmission through the tip is spatially limited to an optical aperture of a 100-nm dimension.

We introduce powder blasting using a pressurised nozzle and a metallic mask as a new promising technology for microsystem fabrication. We study basic parameters of this powder blasting erosion process as well as mask-geometry effects on the erosion rate. We Ž . demonstrate the application potential of this technique in three important fields of microsystems research: i the realisation of Ž . microfluidic chips for biochemical separations, ii the micropatterning of composite hard magnetic layers for mechatronic and magnetic Ž . sensor applications, and iii the realisation of inertial sensors in glass. We present for the first time a mechanical and electrical characterisation of powder-blasted accelerometer devices. q

We demonstrate the feasibility of a powder blasting micro-erosion process for the micromachining of accelerometer devices in glass. Using high-speed abrasive microparticles and a metal contact mask, we structure millimeter-size cantilever beams from simple glass slides. By metalizing one side of the glass substrate, we demonstrate both capacitive and piezoresistive/strain gauge detection of the vibrating cantilever mass and measure the frequency response of mechanically excited cantilever beams. We think that our approach opens new perspectives for manufacture of inertial sensing devices in a technology alternative to Si.[664]

We introduce powder blasting for the fabrication of glass microchips. Powder blasting is a fast and cheap technique with which we pattern channels in sodalime and pyrex glass with a width down to 100 mm. We combine the technique with appropriate bonding procedures to realise sealed microchannel structures. We study the transport of¯uorescent dye solutions and¯uorescent beads within channels made by powder blasting and in`classical' channels made by HF-etching. We ®nd a remarkable difference in sign of the electric ®eld induced¯ow for both types of channels and explain the observed strong plug broadening effects in the powder blasted channels. #

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