When we think about singularities, we tend to think of huge black holes in distant galaxies or a far-off future with runaway AI, however singularities are all around us. Optical singularities typically take place when the phase of light with a particular wavelength, or color, is undefined. Now, scientists from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have established a brand-new way to control and shape optical singularities. The singularity engineering treatment was likewise applied to creating more unique singularities, such as a polarization singularity sheet. The above image reveals scanning electron microscopic lense images of titanium dioxide nanostructures that were used to specifically form the wavefront of light in producing the singularity sheets.

Cross-section of the designed heart-shaped stage singularity sheet. The extended dark area in the center image is a cross-section of the singularity sheet.
When we consider singularities, we tend to believe of huge great voids in distant galaxies or a far-off future with runaway AI, however singularities are all around us. Singularities are just a place where particular criteria are undefined. The North and South Pole, for example, are whats called coordinate singularities since they do not have a defined longitude.
Optical singularities usually take place when the stage of light with a particular wavelength, or color, is undefined. These regions appear entirely dark. Today, some optical singularities, including optical vortices, are being checked out for usage in optical communications and particle adjustment however scientists are just beginning to comprehend the potential of these systems. The concern stays– can we harness darkness like we utilized light to develop powerful, new technologies?
Now, scientists from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have actually developed a brand-new method to control and form optical singularities. The strategy can be utilized to engineer singularities of many shapes, far beyond easy curved or straight lines. To demonstrate their method, the scientists created a singularity sheet in the shape of a heart.

The singularity engineering treatment was likewise used to developing more exotic singularities, such as a polarization singularity sheet. Here, the polarization properties (e.g. polarization azimuth, ellipticity angle, and strength) of the speculative structured light field is compared to the mathematical forecasts. Credit: Daniel Lim/Harvard SEAS
” Conventional holography methods are great at forming light, but struggle to form the darkness,” said Federico Capasso, the Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering at SEAS and senior author of the paper. “We have actually shown on-demand singularity engineering, which opens up a vast set of possibilities in extensive fields, from super-resolution microscopy methods to brand-new atomic and particle traps.”
The research study is published in Nature Communications..
Capasso and his group used flat metasurfaces with precisely-shaped nanopillars to form the singularities..
” The metasurface tilts the wavefront of light in a really precise manner over a surface so that the interference pattern of the transmitted light produces extended regions of darkness,” said Daniel Lim, a college student at SEAS and very first author of the paper. “This technique permits us to exactly engineer dark regions with incredibly high contrast.”.
Metasurfaces, which are nanostructured surfaces containing shapes like nanopillars (left) and nanofins (right), were utilized to recognize these singularity structures experimentally. The above image reveals scanning electron microscopic lense images of titanium dioxide nanostructures that were used to exactly form the wavefront of light in producing the singularity sheets. Credit: Daniel Lim/Harvard SEAS.
Engineered singularities might be utilized to trap atoms in dark areas. These singularities could also improve super high-resolution imaging. While light can only be focused to areas about half a wavelength (the diffraction limitation) in size, darkness has no diffraction limitation, indicating it can be localized to any size. This permits darkness to communicate with particles over length scales much smaller sized than the wavelengths of light. This could be utilized to offer info on not just the size and the shape of the particles but their orientation also.
Engineered singularities could extend beyond waves of light to other kinds of waves.
” You can likewise craft dead zones in radio waves or quiet zones in acoustic waves,” said Lim. “This research study points to the possibility of developing complicated geographies in wave physics beyond optics, from electron beams to acoustics.”.
Referral: “Engineering phase and polarization singularity sheets” by Soon Wei Daniel Lim, Joon-Suh Park, Maryna L. Meretska, Ahmed H. Dorrah and Federico Capasso, 7 July 2021, Nature Communications.DOI: 10.1038/ s41467-021-24493-y.
The Harvard Office of Technology Development has protected the intellectual residential or commercial property associating with this task and is checking out commercialization opportunities.
The research was co-authored by Joon-Suh Park, Maryna L. Meretska, and Ahmed H. Dorrah. It was supported in part by the Air Force Office of Scientific Research under award number FA9550- 19-1-0135 and by the Office of Naval Research (ONR) under award number N00014-20-1-2450.

By Harvard John A. Paulson School of Engineering and Applied Sciences
July 13, 2021