Optical bandpass filters aid fast 3D imaging
Optical bandpass filters have been used in an experimental setup to demonstrate how volume holographic (VH) imaging can resolve images at different depths within a 3D target.
In biomedicine, this has important implications, enabling fine details on cells to be brought into focus without the need for scanning mechanisms.
A team at National Taiwan University worked on the project, which has been published by the SPIE Newsroom, the media site of the international society for optics and photonics.
They explain that scanning methods require moving parts and, despite ongoing efforts, introduce a delay due to the scanning speed.
Digital holographic microscopy is an alternative, but has always required complex computing to reconstruct images.
Now the team say their VH imaging method leverages Bragg filtering to capture multi-plane images in real time, with no need for scanning.
As an example, they report how optical bandpass filters centred on 500nm with a 40nm bandwidth were used to illuminate breast cancer cells, to test the detection of weak phase features.
“The spatial filter-coded VHs significantly enhance the image contrast of the fine structures and enable detailed weak phase features on different planes to be visualised,” the researchers report.