The methods and applications of a surface plasmon resonance-enhanced
marking technique are disclosed. The technique uses surface plasmon
resonance (SPR) excited nanoparticles and a surface plasmon resonance
source in nonlinear interactions with nearby chemical substances and
medium for marking purposes. The SPR-enhanced absorption and fluorescence
rates of chemical substances or medium and nonlinearity of SPR
interactions with chemical substances or medium make the proposed method
suitable for marking fragile materials including biomaterials, such as
writing on thin plastic foils or DNA-protein crosslinking. The marking
method can also be applied to a three-dimensional recording and read out
information system with subwavelength resolutions, coding information of
secrete documents, drug delivery, tissue surgery, tattoo writing or
removal, photodynamic therapy, cosmetic and dermatological treatment.