The detection system (100) also comprises optical means (112) adapted for guiding said excitation radiation aside the at least one detector element (106).

The sensor comprises an excitation radiation source (1) for irradiating the sample (4) and exciting the optically variable molecule (9), thus generating a luminescence signal (7).

The results calculated show: collisional excitation radiations emitted are more important than chemiluminescent radiations; infrared radiations are more important than visible radiation.