PHOTO-THERMAL SENSOR

摘要

The invention relates to a photo-thermal sensor in which a thermal lens is produced in a sample (11) by an exciting light source (4); the change in the refractive index is recorded via detectors (5, 6) by a detecting laser beam (3). According to the invention, the detecting laser beam is applied to a lens (8) and is broadened so that its radius at the sample (11) is at least five times as great as the radius of the throat in the exciting light source (4).