Researchers develop world's smallest silicon-based LED

Researchers have created the world's smallest silicon LED and holographic microscope, further improving smartphone applications and turning cameras into easy-to-carry high-resolution microscopes.

Although photonic chips have made progress in the field of lighting, it is difficult to integrate a small, bright on-chip light emitter, so manufacturers generally use off-chip light sources. However, this light source has low energy efficiency and limits the expansion of photonic chips. sex.

Now researchers from the Singapore-MIT Alliance for Research and Technology (SMART) have developed the world's smallest silicon LED, less than 1 micron wide and rivaling the intensity of larger silicon LEDs, making off-chip emitters possible A product of the past.

The researchers placed their mini silicon LEDs in 55-nanometer CMOS on a chip along with other optoelectronic components.

To test how the LEDs might work in the real world, they placed them in a lensless holographic microscope, which is smaller and less expensive than a regular microscope. The researchers use a light source to illuminate the sample, allowing the light to scatter onto a CMOS digital image sensor to form a digital hologram, which is then processed by a computer to generate the image.

However, reconstructing images with this microscope can be somewhat difficult because you need to know the aperture of the light source, its wavelength, and the distance from the sample to the sensor. For this, the researchers used a neural network algorithm to reconstruct the objects observed with the holographic microscope.

The researchers found that the holographic lens provides more precise, high-resolution images than ordinary light microscopes, with a resolution of about 20 microns, which is smaller than human skin cells (20 to 40 microns in diameter) and white blood cells (30 microns).

The researchers believe these studies could help reconstruct microscopic objects, such as human tissue samples and plant seeds, and could also be used with existing smartphone lenses to convert the phone into high-resolution images by simply modifying the phone's silicone chip and software. rate microscope.

Study author Rajeev Ram said that the new LED is expected to become an ideal choice for bioimaging and biosensing applications due to its wavelength relationship, coupled with its high intensity and nanoscale emission area.