| 摘要 |
PURPOSE:To enable the detection of any fine magnetic field with a larger output efficiency by forming a medium with a Faraday rotational capacity of a magnetic garnet thin film magnetized in the light transmitting direction. CONSTITUTION:Outputs of an LED1 enters an optical fiber 2 to be introduced to a magnetic field detecting section A and made parallel with a lens 3. The detecting section A includes a polaroid element 4, a magnetic parnet thin film 5 and a Wollaston prism 6, in such a manner that the vibration direction of light from the polaroid element 4 is set at 45 deg. to the main axis of the prism 6. The prism 6 separates the incident light into two linear polarized waves, which are converged with lenses 3-1 and 3-2 and then, enters optical fibers 2-1 and 2-2. The emitted light is detected with a photo diode to be monitored by a specified computation. The thin film 5 are composed of n layers of thin films stacked in the area which meets the requirement of m(1-R)<2(n-1)>>1 and the thickness thereof in the light transmitting direction is so set to maximize the figure of merit. |
