Latest Federico Capasso Stories

Harvard School of Engineering and Applied Sciences At a time when communication networks are scrambling for ways to transmit more data over limited bandwidth, a type of twisted light wave is gaining new attention. Called an optical vortex or vortex beam, this complex beam resembles a corkscrew, with waves that rotate as they travel. Now, applied physicists at the Harvard School of Engineering and Applied Sciences (SEAS) have created a new device that enables a conventional optical...

In Harvard's Pierce Hall, the surface of a small germanium-coated gold sheet shines vividly in crimson. A centimeter to the right, where the same metallic coating is literally only about 20 atoms thicker, the surface is a dark blue, almost black. The colors form the logo of the Harvard School of Engineering and Applied Sciences (SEAS), where researchers have demonstrated a new way to customize the color of metal surfaces by exploiting a completely overlooked optical phenomenon. For...

Harvard researchers create a light wave that propagates without spreading An international, Harvard-led team of researchers have demonstrated a new type of light beam that propagates without spreading outwards, remaining very narrow and controlled along an unprecedented distance. This "needle beam," as the team calls it, could greatly reduce signal loss for on-chip optical systems and may eventually assist the development of a more powerful class of microprocessors. Based at the Harvard...

Ultrathin wafer of silicon and gold focuses telecom wavelengths without distortion Applied physicists at the Harvard School of Engineering and Applied Sciences (SEAS) have created an ultrathin, flat lens that focuses light without imparting the distortions of conventional lenses. At a mere 60 nanometers thick, the flat lens is essentially two-dimensional, yet its focusing power approaches the ultimate physical limit set by the laws of diffraction. Operating at telecom wavelengths...

  Defying the laws of reflection and refraction Exploiting a novel technique called phase discontinuity, researchers at the Harvard School of Engineering and Applied Sciences (SEAS) have induced light rays to behave in a way that defies the centuries-old laws of reflection and refraction. The discovery, published this week in Science, has led to a reformulation of the mathematical laws that predict the path of a ray of light bouncing off a surface or traveling from one medium into...

Breakthrough elliptical cavity enables a wide range of applications in photonicsUtilizing a century-old phenomenon discovered in St. Paul's Cathedral, London, applied scientists at Harvard University have demonstrated, for the first time, highly collimated unidirectional microlasers.The result of a collaboration with researchers from Hamamatsu Photonics in Hamamatsu City, Japan, and the Institute of Theoretical Physics of the University of Magdeburg, Germany, the advance has a wide range of...

Advance in metamaterials leads to a new semiconductor laser suitable for security screening, chemical sensing and astronomyA collaborative team of applied scientists from Harvard University and the University of Leeds have demonstrated a new terahertz (THz) semiconductor laser that emits beams with a much smaller divergence than conventional THz laser sources. The advance, published in the August 8th issue of Nature Materials, opens the door to a wide range of applications in terahertz...

Scalable devices inspired by nature exhibit customizable optical properties suitable for applications ranging from highly sensitive sensors and detectors to invisibility cloaksImagine creating novel devices with amazing and exotic optical properties not found in Nature"”by simply evaporating a droplet of particles on a surface.By chemically building clusters of nanospheres from a liquid, a team of Harvard researchers, in collaboration with scientists at Rice University, the University of...

Self-assembly method yields materials with unique optical propertiesScientists from four U.S. universities have created a way to use Rice University's light-activated nanoshells as building blocks for 2-D and 3-D structures that could find use in chemical sensors, nanolasers and bizarre light-absorbing metamaterials. Much as a child might use Lego blocks to build 3-D models of complex buildings or vehicles, the scientists are using the new chemical self-assembly method to build complex...

Adaptable technology opens the door to a wide range of applications in chemical detection, climate monitoring and communicationsAn international team of applied scientists from Harvard, Hamamatsu Photonics, and ETH Zürich have demonstrated compact, multibeam, and multi-wavelength lasers emitting in the invisible part of the light spectrum (infrared). By contrast, typical lasers emit a single light beam of a well-defined wavelength. The innovative multibeam lasers have potential use in...