Chinese researchers develop new photonic chips for high-contrast image

Chinese researchers have developed a planar photonic chip with tailored angular transmission to obtain high-contrast optical microscopic images.

Researchers from the University of Science and Technology of China have discovered that using a planar photonic chip with tailored angular transmission as the sample substrate, a standard bright-field microscopy can provide both darkfield and total internal reflection (TIR) microscopy images with one experimental set-up.

Bright-field microscopy is one of the simplest optical microscopy, which uses light rays to produce a dark image against a bright background. However, the limitations of bright-field microscopy include low contrast for weakly absorbing samples and low resolution due to the blurry appearance of out-of-focus material.

Although darkfield microscopy and TIR microscopy can solve the problem of low contrast, they need complex optical elements which are difficult to integrate and operate due to their large size.

The new planar photonic chip eliminates the need for a bulky condenser or special objective to realize darkfield or TIR illumination. Thus, it can work as a miniaturized high-contrast-imaging device for the development of versatile and compact microscopes, according to the research article published in the journal Nature Communications.

The photonic chip is simple in structure, easy to integrate, low in cost and easy to operate, said Zhang Douguo, leader of the research team and a professor at the university, adding that it can be applied to produce the images of both specimens in the air and living cells in the liquid environment.