| 摘要 |
PURPOSE:To convert the intensity of a magnetic field to an electric signal easily and accurately, by using the effect which is produced when the magnetic field is applied to a magnetic fluid. CONSTITUTION:The angle of the oscillation direction of the vector of a linearly polarized light, which is transmitted through a polarizer 6, to the (y) axis is denoted as phi. A vector H of the magnetic field applied to a magnetic fluid 7 is in the plane on (x) and (y) axes, and the vector projected to the (y) axis is denoted as H'. The magnetic fluid through which the light can be transmitted has a property of double refraction when this magnetic fluid is exposed to the magnetic field; and if lights oscillating in (z) and (x) directions are called an ordinary light and an extraordinary light respectively, a phase difference delta is generated between the ordinary light and the extraordinary light transmitted because of the double refracting property of the magnetic fluid 7, and this value is proportional to the difference between respective refractive indexes of the ordinary light and the extraordinary light and becomes a function of the absolute value of the vector H'. When these lights are transmitted through an analyzer 8, they become a light having the intensity proportional to cos<2>(psi-psi')- sin2psi.sin2psi'.sin<2>(delta/2) (psi' is the oscillation direction of the light transmitted through the analyzer 8), and this light is converted to an electric signal by a photodetector 12, and thus, the magnitude of the vector H' is converted to that of the electric signal in 1:1. |
