Method of identification of petroleum compounds using frequency mixing on surfaces

A computer-readable medium comprising machine-executable instructions for estimating a chemical composition of a material in a borehole penetrating the earth by performing a method comprising:

• placing an analysis unit into the borehole;
• placing a sample of the material onto an enhanced surface of the analysis unit, the enhanced surface comprising a feature configured to increase the electric susceptibility of the sample at an interface between the sample and the enhanced surface;
• illuminating the sample at the interface with a first light beam and a second light beam;
• measuring sum frequency light generated from the illuminating;
• and
• analyzing the sum frequency light to estimate the chemical composition of the material.

An apparatus for estimating a chemical composition of a material in a borehole penetrating the earth, the apparatus comprising:

• a carrier;
• and
• an analysis unit disposed at the carrier, the analysis unit comprising an enhanced surface, a first light source and a second light source, and a light detector, the enhanced surface comprising a feature configured to increase an electric susceptibility of the sample at an interface between the sample and the enhanced surface;
• wherein the analysis unit is configured to receive a sample of the material from a downhole environment onto the enhanced surface, illuminate the material at the interface with the light sources, and measure a characteristic of sum frequency light generated from the illumination with the light detector to estimate the chemical composition.