Spaceplate testing shows great promise for miniaturization of optical systems

Optical systems typically require a lot of free space for incoming diffracting light to be redistributed. In an attempt to miniaturize optical systems, theorists have recently proposed an optical element called a spaceplate that could mimic free space diffraction in a much smaller space.

Mrnka et al. tested a spaceplate for the first time under real-world conditions. Their results showed the spaceplate was able to replicate the optics of a system six times longer.

“Spaceplates have a great potential to massively reduce the size of a plethora of not only optical systems such as cameras, microscopes, telescopes and spectrometers, but also microwave systems like communication antennas, radiometers, radars and more,” said author Michal Mrnka.

The researchers decided to test a spaceplate in a microwave optical system first, since the element’s fabrication requirements are easier at longer wavelengths. After fabrication, they set up an optical system with a transmitting microwave antenna to one side of the spaceplate.

Measuring the microwaves that passed through the spaceplate, the team found a vast compression in the space needed for the optical system. Additionally, they theoretically showed that changing the reflectivity of the mirrors that constitute the spaceplate can enhance the compression effect.

“We believe our work can be used as a steppingstone for future research in this new field of space compression optics,” Mrnka said. “More importantly, we hope real world applications will soon follow in higher frequency regions of the electromagnetic spectrum, including the visible range.”

Source: “Space squeezing optics: Performance limits and implementation at microwave frequencies,” by Michal Mrnka, Euan Hendry, Jaroslav Láčík, Rachel A. Lennon, Lauren E. Barr, Ian Hooper, and David B. Phillips, APL Photonics (2022). The article can be accessed at https://doi.org/10.1063/5.0095735 .