Sensor system with plasmonic nano-antenna array

A method of preparing a plasmonic nano-antennae array structure by performing the following steps:

• a. pretreating a solid substrate having a solid substrate surface with a 3-Mercaptopropyltrimethoxysilane vapor (MPS vapor) to form a self-assembling monolayer (SAM) on the solid substrate surface, the pretreating comprised of exposing the solid substrate surface to the MPS vapor followed by a dehydration process;
• b. acquiring a water-filled Langmuir-Blodgett trough system having a water/air interface, at least one barrier, each barrier being movable, at least one surface pressure sensor, and a dipping device that lowers or raises the solid substrate through the water/air interface that controls dipping time;
• the barrier movements and dipping rates being coordinated to maintain precision control over the dehydration process;
• c. preparing a plurality of capped nanoparticles by combining a plurality of nanoparticles with a plurality of capping molecules, the capping molecules being selected from the group consisting of donor ligands, linear polymer, surfactants and polyelectrolytes, and a combination thereof, and the nanoparticles being selected from the group consisting of gold (Au), Silver (Ag), Rhodium (Rh), Palladium (Pd), Osmium (Os), Iridium (Ir), Platinum (Pt), Titanium (Ti) and Aluminum (Al), and a combination thereof;
• d. spreading a monolayer of the capped nanoparticles on the water/air interface;
• e. depositing the self-assembling monolayer (SAM) of the capped nanoparticles onto the solid substrate surface using the Langmuir-Blodgett trough by precisely controlling the dipping time in coordination with each surface pressure sensor and a movement of at least one barrier thereby producing a plurality of capped nanoparticles wherein the capped nanoparticles deposited on the solid substrate surface having a well-defined structure with a predetermined size, thickness and nano-gap dimensions between the capped nanoparticles;
• f. drying the solid substrate in air, the solid substrate thereby creating a strongly bonded, stable and uniform monolayer array of the capped nanoparticles.

A sample collection and analysis system comprising:

• a precision sensing unit that includes a 3D plasmonic nano-antenna array structure that is uniformly deposited on a surface of an optical fiber bundle;
• a Raman-Scattering gas sensor system with a uniquely designed vapor sampling device;
• system software;
• a unit comprising a laser, a Ramon spectrometer, a microcomputer and an air vacuum pump;
• the database having a plurality of molecular spectrum profiles;
• a wand attached to the unit, the wand having a suction head and a special head gas flow channel;
• the optical fiber bundle being secured with a frame such that when one or more air samples are drawn into the suction head's gas flow, the air samples passing through the optical fiber bundle-thereby producing scattered laser light;
• the scattered laser light is guided through optical lenses and filters back through optical fibers in the wand and into the unit's Ramon spectrum analyzer which produces spectrum data, the spectrum data being fed to the microcomputer, the microcomputer analyzing and comparing the plurality of molecular spectrum profiles with a spectrum of data profiles stored in memory and outputs a best match.