The world’s smallest silicon LED microscope turns your phone camera into a portable 3D microscope
Researchers have created the world’s smallest silicon LED microscope and 3D microscope, opening up a wide range of potential applications, which would turn a smartphone camera into a high-resolution portable microscope, New Atlas reports, citing the journal Nature Communications.
Photon Science
Photonics is the field of technology concerned with the transport and properties of photons, which has led to advances in photonics and thus innovations across a broad range of fields, including optical data communications, imaging, life sciences, healthcare, lighting and displays.
While photonic chips, which are microchips containing two or more photonic components that make up a working circuit, have come a long way in the field of illumination, integrating a small, bright light emitter on a chip has remained elusive. Manufacturers typically use an off-chip light source, which has low power efficiency and limits the scalability of optical chips.
light emitting diode
Now thanks to researchers from Singapore, in collaboration with MIT Research and Technology, the world’s smallest silicon LED at less than a micrometer wide has been developed, with an intensity comparable to larger silicon LEDs.
Previous emitters were difficult to integrate onto the chip into standard complementary metal semiconductor platforms CMOS, which is an integrated circuit built on a printed circuit board, the semiconductor technology used in most chips today. In cell phones, CMOS is used as the “eye” of the camera.
To achieve the revolutionary innovation, LED researchers placed a tiny silicon LED light emitter in a 55-nm CMOS node, along with other photonic and electronic components, on a single chip.
Reality test
To test how the tiny light emitter could be used in real-world situations, the researchers placed it in a lensless 3D microscope. Lensless microscopes are smaller than standard microscopes and are less expensive because they do not require complex and precise lens systems. The researchers used a light source to illuminate a sample. The light is then scattered onto a CMOS digital image sensor, creating a digital hologram that a computer processes to produce an image.
Overcoming difficulties
There can be difficulties with the lensless stereomicroscope in image reconstruction. Accurate reconstruction usually requires detailed knowledge of the aperture, wavelength of the light source, and sample-to-sensor distance. To address this difficulty, the researchers used a neural network algorithm to reconstruct the objects seen by a holographic microscope. Neural networks are computer systems that mimic the networks of the human brain, and rely on training data to learn and improve their accuracy over time.
Ultimate accuracy
The researchers discovered that their 3D lens provided high-resolution images that were much more accurate than an ordinary light microscope. The researchers calculated and measured its accuracy, and found it to be about 20 micrometers (microns). For context, a human skin cell is 20 to 40 microns in diameter; A white blood cell is about 30 microns across.
Extensive applications
The researchers anticipate many applications for the next generation of microLEDs and neural networks integrated with CMOS, including the reconstruction of microscopic objects such as human tissue samples and plant seeds, bioimaging, biosensing applications such as near-field microscopy, and implantable CMOS devices. The researchers say it could be used in existing smartphone cameras by simply modifying the phone’s silicon chip and software, turning the phone into a high-resolution microscope.