Biosensors are disclosed which include a surface for binding to sample molecule to the biosensor in the form of a porous, thin film of dielectric material, e.g., TiO2. In one example the porous, thin film is in the form of a multitude of sub-micron sized rod-like structures (“nanorods”) projecting therefrom. In one embodiment, the biosensor is in the form of a photonic crystal biosensor. The approach of depositing a thin film of dielectric nanorods may be applied to any enhanced fluorescence biosensor surface structure, including 1-dimensional photonic crystals, 2-dimensional photonic crystals, 3-dimensional photonic crystals, surface plasmon resonance surfaces, planar waveguides, and grating-coupled waveguides. The dielectric nanorod structures can be fabricated on the surface of a biosensor by the glancing angle deposition technique (GLAD).