Lifetime imaging with optical fibers

Abstract

Lifetime-imaging has quickly become a standard tool for many applications in biology, medicine, and engineering. Luminescence lifetime is dependent on the chemical environment surrounding the lumiphore so lifetime images give scientists far more chemical information than traditional images. Most lifetime imaging systems require the sample to be brought to the sample stage of a fluorescence lifetime microscope or other lifetime imaging set-up. We are developing lifetime- based fiber-optic imaging systems and sensors for a variety of in-situ measurements. In this work, small diameter optical imaging guides are used to carry light from an excitation source to a remote, or in-situ, sample and also to return the resulting luminescence image through the same image guide to a time-resolved imaging detector. For example, we have developed lifetime-based fiber-optic water and oxygen imaging sensors with the sensing chemistry directly attached to the distal tip of an image guide. These sensors use a pulsed excitation source and a gated camera (ICCD) to collect the images. In addition, we are developing a dual-pulse lifetime imaging system for remote imaging without a gated detector. This paper will report on the current status of our lifetime- based fiber-optic imaging sensors, dual-pulse methods and potential applications.