Holographic microscopy allows the observation of objects in three dimensions, including the internal structures of cells or tissues. Unlike traditional microscopes, it also analyzes the phase of light, revealing invisible details.
Thanks to a 3D printer, Japanese researchers have designed a low-cost, easy-to-use digital microscope. Everything revolves around a smartphone that reconstructs holograms in real time.
This technology was previously bulky, requiring powerful computers for the necessary calculations. Now, a smartphone is enough thanks to an innovative calculation method, dual-step Fresnel diffraction.
A light beam illuminates a sample and interacts with a reference beam. This light pattern, or hologram, is captured by a camera connected to a smartphone via USB. The phone then reconstructs a 3D image.
A laser beam illuminates the sample, while a second beam, called the reference beam, serves as a comparison. The interference between these two beams creates a complex light pattern, or hologram, which is captured by a camera connected to the smartphone via a USB port. With a dedicated app, the smartphone analyzes and processes this data to reconstruct a detailed 3D image of the sample, allowing observation of both its internal and external structures.
This new method allows for rapid processing of holograms, reaching almost two frames per second. The speed is sufficient to observe stationary objects in near real-time. The smartphone app, easy to use, allows zooming in on the image with a simple gesture. This advancement could make 3D microscopy accessible to everyone, even outside laboratories.
Medical applications are being considered, particularly in developing countries where infrastructure is lacking. This microscope could help diagnose diseases such as sickle cell anemia in the field.
Researchers are already working on improving the system. Deep learning, a form of artificial intelligence, could soon eliminate parasitic images, making observations even more precise.
Article author: Cédric DEPOND