3D imaging is traditionally acquired by constructing an image from a series of 2D planes of the object, shot from different angles. Some techniques for producing 3D holograms of objects rely on analyzing a number of incoherently illuminated images of the input. However, the scientists say these holographic technologies are not feasible enough to be widely used. “This is a slow process that is restricted to microscope objectives that have less than optimal resolving power. For this reason, holography currently is not widely applied to the field of 3-D fluorescence microscopic imaging” – said Brooker.
FINCH technology first records three sequential images of light reflected from the illuminated object. Before these holograms are captured, the reflected light is propagated through a diffractive optical element (DOE), which can be used in different phase factors. This enables a reliable reconstruction process of the object by super-positioning the three individual holograms and outputting a “Fresnel hologram”.
The FINCH method was demonstrated in an experiment that produced a hologram of three white letters written on a black background. Each letter was positioned differently with respect to a shared optical source. By using a different phase constant of the DOE, the scientists created the initial holograms in such way that each optimally focused on an individual letter – the final hologram was simply a superposition of the three images.
The scientists used the so-called “FINCHSCOPE”, a state-of-the-art 3D microscope capable of ‘photographing’ multiple planes at once, in order to capture 3D images of moving objects. “Researchers now will be able to track biological events happening quickly in cells,” – said Joseph Rosen, co-inventor and Professor of electrical and computer engineering at BGU. “In addition, the FINCH technique shows great promise in rapidly recording 3-D information in any scene, independent of illumination,” he said.
The research was funded by the National Science Foundation grant and “CellOptic” – a company founded by Brooker and Rosen, which owns the FINCH technology.
TFOT has previously covered a number of innovative holography technologies, such as MIT’s holographic video, and Actuality Systems’ Perspecta display – a true three-dimensional display that allows users to view moving objects from any angle with the unaided eye. You can also check out our article about the very first holographic keyboard.
More information about the FINCH technology can be found on Johns Hopkins University website.