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The specific conical shape of the axicon makes them well suited for the generation of so-called Bessel beams. We present here a technological micro-glass blowing platform developed for miniaturization of micro-optical components. This employs the glass-blowing process, silicon micromachining and heterogeneous bonding. Here, we focus on the unconventional fabrication methods of micro-optical components in borosilicate glass. As an example, an original concept of a micro-machined micro-axicons for generation of Bessel beams is demonstrated and experimentally validated.

As intracardiac signal amplitudes fluctuate due to patient activity, drug intake, and other factors, it is imperative that an adequate sensing safety margin in an implanted pacemaker be used to compensate. We studied an investigational autosensing feature that automatically adjusts the device's sensitivity. Data were collected from 55 patients, with Intermedics model 292-03 or 294-03 pacemakers, upon inclusion of the study (Visit 1); 1 month postinclusion (Visit 2); 1 month, 1 day postinclusion (Visit 3); then 1 month, 2 days postinclusion (Visit 4). Atrial (N = 45) and/or ventricular (N = 54) thresholds were assessed at each visit; during Visit 2, myopotential tests were performed at two sensitivity settings. Autosensing was activated following Visit 1, then programmed on randomly at Visit 2 or Visit 3. From Visit 2-Visit 4, patients were monitored during daily activities (D), exercise (E), and sleep (S) with 24-hour Holter. With Autosensing on, atrial undersensing episodes were D = 33 (P > 0.2), and S = 28 (p 0.5). Ventricular oversensing episodes were S = 2; atrial oversensing episodes were S = 34 (p > 0.5), D = 2, and E = 3. Comparing Autosensing adjusted sensitivity with the recommended 2:1 safety margin, 4 patients (p = 0.15) experienced atrial myopotential oversensing, and 2 patients (p = 0.15) ventricular. No unanticipated clinical events occurred. Compared with the recommended 2:1 sensing safety margin, the Autosensing feature performed equal to manual programming in preventing episodes of under/oversensing, and was better for atrial undersensing during sleep. Autosensing obviates the need for periodic reprogramming of a fixed sensitivity value.

The large bandgap of SiC makes the recombination mechanism the main process in determining the forward current in a large range of temperature. We have added the Poole-Frenkel effect to the conventional Shockley-Read-Hall (SRH) term of the numerical device simulator MEDICI. This paper shows the influence of this effect on SiC. >