Surface Enhanced Infrared Absorption Spectroscopy is a variation of infrared spectroscopy where signal enhancement is achieved by functionalization of the crystal with a metal film.
The Molecules adsorbed on this metal layer show an infrared absorption which is 10-1000 times higher. This effect is calles Surface Enhanced Infrared Absorption (SEIRA) and results from the electromagnetic interactions of the incident photon field with the metal and the molecules.
These crystals have recently been tested by researchers in Canada. You can read more about this in their publication on Electrochemical ATR-SEIRAS.
Please note that these crystals come without the gold layer.