Contact: Angela Stark
Optical Society of America
Caption: In transmission mode, the holographic microscope has a wider field of view than in reflection mode. While in this orientation, the device can be used to search for pathogens in large volumes of see-through materials, such as blood or water. (a) The beam cube, which splits the laser into two beams in reflection mode, is removed. Laser light from a laser diode (“LD”) is projected through a pin hole (“PH”) and passes directly through a see-through sample. Light that hits individual cells or particles in the sample is scattered; this scattered light forms an interference pattern with light that has not encountered any obstacles on its path through the sample. The interference pattern formed by the encounter between these two sources of light is then recorded on a CMOS image sensor and sent to a computer for analysis. (b) This photograph shows the microscope in transmission mode, with its cover removed. (The inset shows what the microscope looks like with its cover on.)
Credit: Ozcan BioPhotonics Group at UCLA/Biomedical Optics Express.
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