Device for investigating non-linear optical behavior of a layer formed from first and second reactants

A device for ascertaining one of:

• a presence and absence of a binding of a first reactant and a second reactant, wherein upon binding, the first and second reactants form a dipolar layer which displays a non-linear optical behavior at an interface formed between the mutually bound first and second reactants, the device comprising:
• a rectangular housing,
• a transparent sample holder disposed on a wall of said rectangular housing to accommodate the first and the second reactant,
• a radiation source for supplying a radiation beam having at least one discrete frequency, to irradiate the transparent sample holder,
• a detection system for detecting radiation returned from the transparent sample holder having a frequency which differs essentially from said at least one discrete frequency indicating the presence of said dipolar layer, which presence is a result of said binding, wherein the wall of the rectangular housing, within which said radiation source and detection system reside, includes a transparent section which faces the radiation source and detecting system whereupon said transparent sample holder is disposed to be irradiated by said radiation beam.