Flexible hollow optical fiber bundle for infrared thermal imaging

A flexible and coherent bundle of hollow optical fibers was fabricated for infrared thermal imaging. For acquisition of thermal images, differences in the transmission efficiency among the fibers were numerically compensated to obtain high temperature resolution of 1°C for measuring body temperature. In a lens system with 10-fold magnification and hollow fibers of 320-μm inner diameter, the spatial resolution is around 3 mm. The hollow-fiber bundle enables observation of the surface temperature of inner organs and blood flow of the surfaces when the bundle is introduced into the human body with an endoscope.