Patent ID: 7576334

Claim:
A method of measuring fluorophore excited state lifetimes comprising: initiating a first excitation pulse at a dye at a first time point to excite dye molecules of said dye from a ground state to an excited state; initiating a first probing pulse at said dye molecules thereby generating first photoacoustic waves at a second time point; collecting said first photoacoustic waves after said initiation of said first probing pulse; analyzing said first photoacoustic waves relative to a first time delay between said first time point and said second time point to determine a first intensity point; initiating a second excitation pulse at said dye at a third time point to excite dye molecules of said dye; initiating a second probing pulse at said dye molecules thereby generating photoacoustic waves at a fourth time point; collecting said second photoacoustic waves after said initiation of said second probing pulse; analyzing said second photoacoustic waves relative to a second time delay between said third time point and said fourth time point to determine a second intensity point; and determining a slope between said first intensity point and said second intensity point.