An embodiment of the invention is a remote sensor that has an optical fiber terminating in a tip. A thin film porous particle having a characteristic optical response that changes in the presence of an analyte is optically coupled and physically attached to the tip of the optical fiber. The optical response of the particle changes in the presence of analyte, and the particle also serves to concentrate analyte. The thin film porous particle can be functionalized toward sensitivity for a predetermined analyte or analytes. A method of remote sensing exposes the remote sensor to an environment to be monitored for analyte. The thin film porous particle is probed with a beam of light. Reflected light is monitored through the optical fiber for a shift in frequency or intensity.