| abstract |
In a fiber-optical sensor used for measuring the Doppler broadening of scattered laser light by the principle of quasi-elastic light scattering (QELS), the scattered light originating from particles in movement, the emergence surface (7) for the laser light at the end of a single-mode or multimode light guide (3) used as an immersion probe is inclined at an angle 0<φ≦15°, preferably 1°≦φ≦6°, the angle of inclination being de-fined by the optical axis (8) of the light guide (3) and the normal (9) of the emergence surface (7). |