Spectro-temporal optical encoding of information using a time-gated fluorescence resonance energy transfer (FRET)

A method of using a FRET relay assembly, the method comprising:

• providing a FRET relay assembly comprising:
• a long lifetime FRET donor,
• a semiconductor quantum dot (QD) configured as an intermediate acceptor/donor in FRET and assembled to the long lifetime FRET donor in sufficient proximity thereto so as to allow for a first FRET process between the long lifetime FRET donor and the QD and
• a fluorescent dye configured as a terminal FRET acceptor and assembled to the QD in sufficient proximity thereto so as to allow for a second FRET process between the QD and the fluorescent dye,
• wherein the long lifetime FRET donor has an excited state lifetime of at least one microsecond and the QD and fluorescent dye each have excited state lifetimes of less than 100 nanoseconds;
• spectrally exciting the FRET relay assembly;
• and
• receiving a spectral emission from the FRET relay assembly.