Design of a confocal holography microscope for three-dimensional temperature measurements of fluids in microgravity

Abstract

The design of a Confocal Scanning Laser Holography (CSLH) microscope applied to microgravity studies of fluids is described. This microscope generates a hologram for each three-dimensional point describing an object and offers a new, non-intrusive means to determine the three-dimensional temperature and composition of objects, which is useful information for heat and mass transfer studies. The holograms are created from the interference of a ‘known’ reference beam to an ‘unknown’ object beam, which contains the phase information from which the object’s index of refraction is determined. The key feature of the microscope for microgravity experimentation is the object remains stationary as the beam is rastered through the object, ensuring a quiescent environment. Additional vibration disturbances due to the motion of optical components are minimized by applying counter balances and by using the Motion-vibration Isolation System (MIM).