Abstract: A lateral to free flow assay device is provided for analysis of a fluid sample. The device comprises: a sample collection unit configured to introduce the sample into the device; an optical element configured to facilitate TIR for the analysis of the sample; a fluid pathway configured to provide fluid communication between the sample collection unit and a free flow region adjacent the optical element; a wicking pad defining a lateral flow section of the fluid pathway or provided in the sample collection unit to collect the sample; wherein at least one surface of the optical element defines at least part of the free flow region of the fluid pathway; and wherein the fluid pathway is configured to enable fluid flow from the lateral flow region to the free flow region of the fluid pathway to facilitate the analysis of the sample.

Abstract: A method of obtaining spectral information comprises initiating at least a first excitation at a first excitation frequency and a second excitation at a second frequency in a surface enhanced sample. The method further comprises varying one of said first and second excitation frequencies, detecting an output signal having an output signal strength and identifying an output signal peak. In addition the method includes correlating the identified output signal with the first and second excitation frequencies to obtain spectral information, in which the surface enhanced sample substrate is configured to enhance the field corresponding to at least one of the first and second excitation, or output fields initiated in this sample.

Abstract: A method of obtaining spectral information comprises initiating at least a first excitation at a first excitation frequency and a second excitation at a second frequency in a surface enhanced sample. The method further comprises varying one of said first and second excitation frequencies, detecting an output signal having an output signal strength and identifying an output signal peak. In addition the method includes correlating the identified output signal with the first and second excitation frequencies to obtain spectral information, in which the surface enhanced sample substrate is configured to enhance the field corresponding to at least one of the first and second excitation, or output fields initiated in this sample.