Soft lithography was invented in Professor George M. Whitesides group in 1990s.  It represents a conceptually different approach to rapid prototyping of various types of micro- and nanostructures and devices on planar, curved, and flexible substrates at low cost. A number of patterning techniques -- micro-contact printing, replica molding, micro-transfer molding, micro-molding in capillary, solvent-assisted micro-molding, and phase shifting edge lithography form the basis of soft lithography; all are based on printing, molding, and embossing with an elastomeric stamp. New techniques are also emerging. All these techniques share one thing in common: the use of organic materials and polymers - soft matter in the language of physicists.

A typical soft lithography procedure includes four major steps: (1) design of the pattern; (2) fabrication of the mask and the master structure; (3) fabrication of the PDMS stamp; and (4) fabrication of micro- and nanostructures with this stamp by printing, molding, embossing, decal transfer, phase shifting edge lithography, and other procedures. The fabrication of patterned copies using the PDMS stamp is what is usually referred to as soft lithography; the overall process from design of the pattern to fabrication of functional structures is sometimes (when the convenience of the method for rapid generation of functional structures is the feature emphasized) referred to as rapid prototyping.
 
We aim to undertake our research pathway to identify the physical origin of SERS and fabricate reproducible plasmonic nanochips for biological and chemical sensing. Specifically, our fundamental studies on important parameters of SERS effect will serve as the basis to direct engineering efforts on the development of SERS as the ultrasensitive analytical platform for chemical, biological and environmental trace detection.