PROBING AND MONITORING AEROSOL AND ATMOSPHERIC CLOUDS WITH AN ELECTROOPTIC OSCILLATOR

Monitoring, probing, and sensing characteristics of aerosol clouds is difficult and complicated. Probing the characteristics of aerosols is most useful in the chemical and microelectronic industry for processin g control of aerosols and emulsion, decreasing bit error rate in adapt ive optical communication systems, and in acquiring data for atmospher ic science and environment quality. We present a new mathematical and optical engineering model for monitoring characteristics of aerosol cl ouds. The model includes the temporal transfer function of aerosol clo uds as a variable parameter in an electro-optic oscillator. The freque ncy of the oscillator changes according to changes in the characterist ics of the clouds (density, size distribution, physical thickness, the medium and the particulate refractive indices, and spatial distributi on). It is possible to measure only one free characteristic at a given time. An example of a practical system for monitoring the density of aerosol clouds is given. The frequency of the oscillator changes from 1.25 to 0.43 MHz for changes in aerosol density ti om 2000 to 3000 par ticulates cm(-3). The advantages of this new method compared with the transmissometer methods are (a) no necessity for line-of-sight measure ment geometry, (b) accurate measurement of high optical thickness medi a is possible, (c) under certain conditions measurements can include c haracteristics of aerosol clouds related to light scatter that cannot be or are difficult to measure with a transmissometer, and (d) the clo ud bandwidth for free space optical communication is directly measurab le. (C) 1996 Optical Society of America