MINIATURIZED MAGNETIC SENSOR

A NOVEL MINIATURIZED MAGNETIC SENSOR IS PROPOSED WHICH OPERATES ON A MOLECULAR LEVEL. RATHER THAN USING A MAGNETIC FIELD TO MODULATE CONDUCTIVITY OR CURRENT FLOW, THE PROPOSED SENSOR MODULATES OPTICAL TRANSMISSION. THE MAGNETIC RESPONSE OF A LIQUID CRYSTALLINE MEDIUM IS GREATLY INCREASED BY THE ADDITION OF CERTAIN SMALL PARTICLES. IN THE LIQUID CRYSTAL MEDIUM THESE PARTICLES SPONTANEOUSLY ALIGN TO FORM SMALL CHAINS. THE MOTION OF THESE CHAINS AFFECTS THE LIQUID CRYSTAL OPTICAL PROPERTIES. THE DEVICE, TO A CERTAIN EXTENT, MIMICS BACTERIA WHICH SENSE THE DIRECTION OF THE EARTH'S MAGNETIC FIELD. THE EFFECT OF THE MAGNETIC FIELD ON THE COMPOSITE OPTICAL MEDIUM CAN BE COUNTERBALANCED BY AN ELECTRIC FIELD SUCH THAT NO CHANGE IN OPTICAL PROPERTIES TAKES PLACE. THE VOLTAGE NECESSARY TO MAINTAIN THIS BALANCE IS A DIRECT MEASURE OF THE MAGNETIC FIELD STRENGTH. BECAUSE OF THIS BALANCING MECHANISM, THE MEASURED MAGNETIC FIELD STRENGTHS CAN BE QUITE LARGE OR SMALL, AND INTERFEROMETRIC METHODS CAN BE APPLIED TO ACHIEVE VERY HIGH SENSITIVITIES. FABRICATION IS COMPATIBLE WITH CURRENT INTEGRATED CIRCUIT AND MICROMINIATURIZATION TECHNOLOGIES.