An international group of physicists from Far Eastern Federal University (FEFU), ITMO University, the Institute of Automation and Control Processes of the Far Eastern Branch of the Russian Academy of Sciences (IAPU FEB RAS), and universities in Hong Kong has achieved a breakthrough in infrared sensing, TASS reported, citing the Russian Ministry of Education and Science. The new laser printing technology for metasurfaces increases the sensitivity of photodetectors by 100,000 times compared to a smooth gold film.

The method is based on a femtosecond laser that does not evaporate but gently deforms a thin gold film, forming an array of microscopic bumps. These structures act as light traps: the incident beam is repeatedly reflected inside, which provides a colossal signal amplification. The device can be tuned to any wavelength from 1.3 to 8 micrometers simply by changing the size of the bumps.

Scientists printed the metasurface directly onto the electrodes of a field-effect transistor with mercury telluride quantum dots. The resulting hybrid photodetector, when cooled to –73 °C, showed record sensitivity for its class. This paves the way for compact IR sensors for medicine, security systems, and industrial diagnostics, as well as for replacing complex and expensive lithography in the production of optical chips. For the defense sector, the technology is particularly critical: highly sensitive infrared sensors are a key element of thermal imagers, homing heads, and drone detection systems.