MSGID: 1:317/3 641932e7   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Ultrafast beam-steering breakthrough    
      
     Date:   
         March 20, 2023   
     Source:   
         DOE/Sandia National Laboratories   
     Summary:   
         n a major breakthrough in the fields of nanophotonics and ultrafast   
         optics, a research team has demonstrated the ability to dynamically   
         steer light pulses from conventional, so-called incoherent light   
         sources.   
      
      
         Facebook Twitter Pinterest LinkedIN Email   
   FULL STORY   
   ==========================================================================   
   In a major breakthrough in the fields of nanophotonics and ultrafast   
   optics, a Sandia National Laboratories research team has demonstrated the   
   ability to dynamically steer light pulses from conventional, so-called   
   incoherent light sources.   
      
      
   ==========================================================================   
   This ability to control light using a semiconductor device could allow   
   low- power, relatively inexpensive sources like LEDs or flashlight   
   bulbs to replace more powerful laser beams in new technologies such as   
   holograms, remote sensing, self-driving cars and high-speed communication.   
      
   "What we've done is show that steering a beam of incoherent light can   
   be done," said Prasad Iyer, Sandia scientist and lead author of the   
   research, which was reported in the current issue of the journal Nature   
   Photonics. The work was funded by the Department of Energy's Office   
   of Science.   
      
   Incoherent light is emitted by many common sources, such as an   
   old-fashioned incandescent light bulb or an LED bulb. This light is called   
   incoherent since the photons are emitted with different wavelengths   
   and in a random fashion. A beam of light from a laser, however, does   
   not spread and diffuse because the photons have the same frequency and   
   phase and is thus called coherent light.   
      
   In the team's research, they manipulated incoherent light by using   
   artificially structured materials called metasurfaces, made from   
   tiny building blocks of semiconductors called meta-atoms that can be   
   designed to reflect light very efficiently. Although metasurfaces had   
   previously shown promise for creating devices that could steer light   
   rays to arbitrary angles, they also presented a challenge because they   
   had only been designed for coherent light sources.   
      
   Ideally, one would want a semiconductor device that can emit light like   
   an LED, steer the light emission to a set angle by applying a control   
   voltage and shift the steering angle at the fastest speed possible.   
      
   The researchers started with a semiconductor metasurface that had embedded   
   tiny light sources called quantum dots. By using a control optical pulse,   
   they were able to change, or reconfigure, the way the surface reflected   
   light and steer the light waves emitted from the quantum dots in different   
   directions over a 70-degree range for less than a trillionth-of-a-second,   
   marking a significant success. Similar to laser-based steering, the   
   steered beam restrained the tendency of incoherent light to spread over   
   a wider viewing angle and instead produced bright light at a distance.   
      
   Taming light A feat previously considered impossible, the team's   
   proof-of-principle work paves the way for developments in the fields of   
   nanophotonics and ultrafast optics. The ability to dynamically control   
   incoherent light sources and manipulate their properties offers a wide   
   range of applications.   
      
   One low-power use would be to brighten military helmet screens used   
   to overlay maps or blueprints over ordinary vision. "In applications   
   where space is valuable," Iyer said, "steering light emission with   
   low-size-and-weight metasurface-LED displays could be made possible in   
   the future with this technology. We can use the light emitted in a better   
   way rather than just turning them off and on."  The technique could   
   also provide a new kind of small display that can project holographic   
   images onto eyeballs using low-power LEDs, a capability of particular   
   interest for augmented and virtual reality devices. Other uses could be   
   in self-driving cars where LIDAR is used to sense objects in the path   
   of the car.   
      
   In terms of expressions of interest, the team has had several inquiries   
   from commercial sources, said Sandia researcher Igal Brener, a paper   
   author and lead scientist on the project. "A commercial product could   
   be 5-10 years out, especially if we want to have all the functionality   
   on-chip," Brener said. "You wouldn't use a control optical pulse to   
   impart the changes in the metasurface needed to steer the light, but   
   rather you would do this control electrically.   
      
   We have ideas and plans, but it's still early. Imagine an LED light   
   bulb that can emit light to follow you. Then you wouldn't waste all that   
   illumination where there's nobody. This is one of the many applications   
   that we dreamed about with DOE years ago for energy efficiency for   
   office lighting, for example."  Similarly, tamed light may one day offer   
   benefits in scenarios where focused illumination is only needed in a   
   specific area of interest, such as surgery or in autonomous vehicles.   
      
   For incoherent light, the future is looking bright.   
      
   Sandia National Laboratories is a multimission laboratory operated by   
   National Technology and Engineering Solutions of Sandia LLC, a wholly   
   owned subsidiary of Honeywell International Inc., for the U.S. Department   
   of Energy's National Nuclear Security Administration. Sandia Labs   
   has major research and development responsibilities in nuclear   
   deterrence, global security, defense, energy technologies and economic   
   competitiveness, with main facilities in Albuquerque, New Mexico, and   
   Livermore, California.   
      
       * RELATED_TOPICS   
             o Matter_&_Energy   
                   # Optics # Graphene # Chemistry # Inorganic_Chemistry   
                   # Physics # Medical_Technology # Weapons_Technology #   
                   Energy_Technology   
       * RELATED_TERMS   
             o Optics o Solar_cell o Lighting o Wave-particle_duality o   
             Electromagnetic_spectrum o Electroluminescence o Photography   
             o Energy_development   
      
   ==========================================================================   
   Story Source: Materials provided by   
   DOE/Sandia_National_Laboratories. Note: Content may be edited for style   
   and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Iyer, P.P., Karl, N., Addamane, S. et al. Sub-picosecond steering of   
         ultrafast incoherent emission from semiconductor metasurfaces. Nat.   
      
         Photon., 2023 DOI: 10.1038/s41566-023-01172-6   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2023/03/230320143821.htm   
      
   --- up 1 year, 3 weeks, 10 hours, 50 minutes   
    * Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)   
   SEEN-BY: 15/0 106/201 114/705 123/120 153/7715 226/30 227/114 229/110   
   SEEN-BY: 229/111 112 113 307 317 400 426 428 470 664 700 292/854 298/25   
   SEEN-BY: 305/3 317/3 320/219 396/45   
   PATH: 317/3 229/426