| 摘要 |
PURPOSE:To enhance the reliability of result of measurement for an optical audio signal by detecting an elastic vibration which generates on the surface of a sample through irradiation of exciting light thereto as a variation in tunnel current, at a position different from a position at which the light is irradiated. CONSTITUTION:When exciting light 3 whose intensity s modulated is irradiated to a sample 2, the sample 2 repeats expansion and contraction which are caused by heat, so as to generate an elastic wave. This means that the distance between the sample 2 and a probe 4 periodically varies. By the way, a tunnel current A exponentially changes in accordance with a variation in the distance between the probe 4 and the sample 2. Accordingly, an elastic vibration of the sample can be obtained by measuring a variation in the tunnel current A. That is, since the elastic vibration can be obtained at any position on the sample 2 with no affection, the reliability of the result of measurement may be enhanced, thereby it is possible to obtain a highly reliable optical characteristic of the sample 2. |
