An optics unit (12) serves to direct radiation produced by the illuminating unit (10) toward the specimen (18) and to direct the radiation emitted by the specimen toward a detector unit (20).

The said blotting element can be moved towards the sample or carrier in a controlled manner.

A light beam is transmitted toward the fluid sample to induce a oscillation frequency in the piezoelectric substrate.

The first light source device radiates first illumination light to the sample through the insertion section.