International Journal of Infrared and Millimeter Waves. Vol. 20, No. 11. 1999 QUASI-OPTICAL SENSORS FOR INVESTIGATION OF ACOUSTO-ELECTROMAGNETIC PHENOMENA OF POPOCATEPETL VOLCANO M. Tecpoyotl-T,1 S. V. Koshevaya,1,2 E. A. Gutierrez-D,1 A. Torres-J, 1 and D. O. Solovjov1 1 National Institute for Astrophysics Optics and Electronics, INAOE P.O. Box 51 & 216 Z. P. 72000, Puebla, Mexico 2Autonomous University of Morelos CIICAp, Av. Universidad No. 10001, Z. P. 62210, Morelos, Mexico Received August 18, 1999 ABSTRACT This article focuses on meteorological electronics based on the space research of acoustic-electromagnetic phenomena caused by Popocatepetl volcano (Mexico). The main purpose is to present two different types of quasi-optical sensors, one of them is formed by a modulator based on a surface oriented p,i,n structure with "deep" junctions; and by a silicon detector (avalanche photodiode with separated regions of absorption and multiplication: APDSAM). This system guarantee both good sensibility and wide range of sensing, sub-millimeter and millimeter range. This sensor has the advantage that can be realized as a planar array. On the other hand, for the remote measurement of basic meteorological parameters and chemical state by means of radiobrightness temperatures (radiometer systems) a low noise receiver on the base of dielectric waveguide and Schottky diodes cooled by means of cryoelectronic element is used. Keywords: meteorological electronics, acousto-electromagnetic phenomena, surface oriented p,i,n structure. I. INTRODUCTION First quasi-optical sensor: the p, i, n modulator and the APDSAM with the following characteristics form it. 1889 0195-9271/99/1100-1889$16.00/0 C 1999 Plenum Publishing Corporation