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Title: Controlling the sign of chromatic dispersion in diffractive optics with dielectric metasurfaces

Diffraction gratings disperse light in a rainbow of colors with the opposite order than refractive prisms, a phenomenon known as negative dispersion. While refractive dispersion can be controlled via material refractive index, diffractive dispersion is fundamentally an interference effect dictated by geometry. Here we show that this fundamental property can be altered using dielectric metasurfaces, and we experimentally demonstrate diffractive gratings and focusing mirrors with positive, zero, and hyper-negative dispersion. These optical elements are implemented using a reflective metasurface composed of dielectric nano-posts that provide simultaneous control over phase and its wavelength derivative. In addition, as a first practical application, we demonstrate a focusing mirror that exhibits a five-fold reduction in chromatic dispersion, and thus an almost three-times increase in operation bandwidth compared with a regular diffractive element. In conclusion, this concept challenges the generally accepted dispersive properties of diffractive optical devices and extends their applications and functionalities.
 [1] ;  [2] ;  [1] ;  [1] ;  [1]
  1. California Inst. of Technology (CalTech), Pasadena, CA (United States)
  2. California Inst. of Technology (CalTech), Pasadena, CA (United States); Univ. of Massachusetts, Amherst, MA (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Additional Journal Information:
Journal Volume: 4; Journal Issue: 6; Related Information: LMI partners with California Institute of Technology (lead); Harvard University; University of Illinois, Urbana-Champaign; Lawrence Berkeley National Laboratory; Journal ID: ISSN 2334-2536
Optical Society of America
Research Org:
Energy Frontier Research Centers (EFRC), Washington, D.C. (United States). Light-Material Interactions in Energy Conversion (LMI)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
42 ENGINEERING; solar (photovoltaic); solid state lighting; phonons; thermal conductivity; electrodes - solar; materials and chemistry by design; optics; synthesis (novel materials); synthesis (self-assembly)
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