New type of photothermal spectroscopic technique

We propose a new type of photothermal spectroscopic technique. The experimental setup is simple and the experiment can be readily carried out, even in the difficult environments that are often required for opticaland surface studies of materials. Features of the method proposed here are nondestructive and noncontact; in addition, the simplicity of our design enables us easily to make the system resistant to vibration and drift, which leads to a high signal-to-noise ratio of the photothermal signal. A few experiments have been conducted to demonstrate the utilization of the method, e.g., a quantum-radiative efficiency of surface polaritons in an air-Ag film-BK-7 prism geometry has been evaluated.