| 摘要 |
PURPOSE:To measure light absorption characteristics with high precision and high sensitivity by irradiating a measurement position of a thin film on a liquid surface with exciting light and also irradiating the measurement position with probe light from below the liquid surface at such an angle that it is reflected totally by the liquid surface. CONSTITUTION:The exciting light 5 from an exciting light source 6 is intensity-modulated 7 to illuminate the measurement position of the thin film 2 on the liquid surface 1. The probe light 8 from a probe light source 9, on the other hand, is irradiated from below the liquid surface 1 at the angle of incidence at which it is reflected totally by liquid surface 1 and the quantity of deflection of the probe light 8 passed through the measurement point is detected 10. Thus, the probe light 8 is reflected totally by the liquid surface 1 without being transmitted through the measurement position of the thin film 2 irradiated with the exciting light 5, so the light is affected by neither the liquid phase nor the vapor phase in which the reflective index varies owing to the absorption of the exciting light 5 by the thin film 2. Further, the center part of the probe light 8 which has the highest light intensity contacts the measurement position where the variation in refractive index is largest, so the quantity of deflection of the probe light 8 is easily detected by the detector 10 and a measurement is taken with high precision and high sensitivity. |
