Sensor utilizing attenuated total internal reflection

A sensor that utilizes attenuated total internal reflection, comprising:

• a light source, for emitting a light beam;
• a measuring unit, constituted by:
• a dielectric block which is transparent with respect to the light beam;
• a thin film layer, which is formed on a surface of the dielectric block;
• and a sample holding mechanism, for holding a sample on the thin film layer;
• an optical system, for causing the light beam to enter the dielectric block at various angles of incidence, such that total internal reflection conditions can be obtained at an interface between the dielectric block and the thin film layer;
• two dimensional imaging means, constituted by a plurality of photoelectric converting elements which are arranged in the vertical and horizontal directions, for detecting the intensity of the light beam, which is totally reflected at the interface;
• and
• measuring means, for measuring the state of attenuated total internal reflection, based on the output from the two dimensional imaging means;
• the photoelectric converting elements of the two dimensional imaging means being arranged such that a first direction in which they are arranged, from between the vertical and horizontal directions, is parallel to a plane that includes the light incident on the interface and reflected light;
• and
• the two dimensional imaging means only outputting the sums of charges of the photoelectric converting elements which are arranged in a second direction, from between the vertical and horizontal directions, not parallel to the plane that includes the incident light and the reflected light.