Science Daily May 2, 2019 A team of researchers (NIST, University of Maryland) has demonstrated how dielectric metasurfaces can be leveraged to shape the temporal profile of a near-infrared femtosecond pulse. Finely tailored pulse shaping operations, including splitting, compression, chirping and higher-order distortion are achieved using a Fourier-transform setup embedding metasurfaces able to manipulate, simultaneously and independently, the amplitude and phase of the constituent frequency components of the pulse. Exploiting metasurfaces to manipulate the temporal characteristics of light expands their impact and opens new vistas in the field of ultrafast science and technology…read more. TECHNICAL ARTICLE
Tag Archives: Photonics
A polariton filter turns ordinary laser light into quantum light
Phys.org February 19, 2016 An international team of researchers (Australia, France) used nanometre-thick films made of gallium arsenide and sandwiched them between two mirrors to manipulate the incoming photons. The photons interact with electron-hole pairs in the semiconductor, forming polaritons that carry properties from both the photons and the electron-hole pairs. The polaritons decay after a few picoseconds, and the photons they release exhibit distinct quantum signatures. While these quantum signatures are weak at the moment, the work opens a new avenue for producing single photons on demand. Once they are able to increase the strength of the quantum signatures, […]
Invisible tags: Physicists write, read and erase using light
Nanowerk February 1, 2019 Researchers in Germany introduced organic luminescent molecules plastic foils. In the beginning, these molecules are in an inactive, dark state. By locally using ultraviolet irradiation, it is possible to turn the dark state into an active, luminescent one. By mask illumination or laser writing, activated patterns can be printed and the imprinted information can be read. Ultraviolet radiation induces a chemical reaction which efficiently removes the oxygen from the layer activating the luminescent molecules. By illuminating with infrared light, the tag is erased completely, and new data can be written into it. The deactivation process is […]
Scientists design new material to harness power of light
Phys.org December 17, 2018 An international team of researchers (USA – MIT, University of Hartford, UK. France) found that several materials with poor nonlinear characteristics can be combined, resulting in a new metamaterial that can be “tuned” to change the color of light. The enhancement comes from the way the metamaterial reshapes the flow of photons. They describe the underlying physics, compare its predictions to the experimental results, and analyze the limits of its applicability. The work opens a new direction in controlling the nonlinear response of materials and may find applications in on-chip optical circuits, drastically improving on-chip communications…read […]
Shedding a new light on optical trapping and tweezing
Eurekalert November 27, 2018 While holographic optical trapping and tweezing is not new, an international team of researchers (South Africa, USA – MIT) found a way to optimally use the full force of light – including vector light to control and manipulate minute objects such as single cells in a human body, tiny particles in small volume chemistry, or working on future on-chip devices. They showed how to create and control any pattern of light holographically, and then used this to form a new optical trapping and tweezing device…read more. Open Access TECHNICAL ARTICLE
Light-bending tech shrinks kilometers-long radiation system to millimeter scale
Phys.org October 26, 2018 A team of researchers in the US (University of Michigan, Purdue University) used a laser to produce a pulse of visible light that lasts for one trillionth of a second. The array of antennae causes the light pulse to accelerate along a curved trajectory inside the crystal. The light pulse displaced electrons from their equilibrium positions to create dipole moments which accelerated along the curved trajectory of the light pulse resulting in the emission of synchrotron radiation much more efficiently at the terahertz range. The work demonstrates that synchrotron radiation could eventually help develop on-chip terahertz […]
U-M researchers develop small device that bends light to generate new radiation
University of Michigan October 25, 2018 Synchrotron radiation is usually generated at large-scale facilities. A team of researchers in the US (University of Michigan, Purdue University) developed a way to produce synchrotron radiation by printing a pattern of microscopic gold antennae on lithium tantalate metasurface. They use a laser that produces ultrashort pulses of light which last for one trillionth of a second. The array of antennae causes the light pulse to accelerate along a curved trajectory inside the crystal producing synchrotron radiation that contains many terahertz frequencies. They hope to refine their device so that the light pulse revolves […]
Novel optics for ultrafast cameras creates new possibilities for imaging
MIT News August 13, 2018 Researchers at MIT exploited time as an extra dimension in the optical design and demonstrated that by folding large spaces in time using time-resolved cavities, one can enable new camera capabilities without losing the targeted information. They demonstrated lens tube compression by an order of magnitude, together with ultrafast multi-zoom imaging and ultrafast multispectral imaging by time-folding the optical path at different regions of the imaging optics. They expect this technique to have a broad impact on time-resolved imaging and depth-sensing optics… read more. TECHNICAL ARTICLE
Trapping light using Tetris-like clusters of crystals
Nanowerk July 10, 2018 Lack of precision and control often produced photonic crystals that have inconsistent defects that jeopardise their commercial performance. Working under a project funded by the EU Future and Emerging Technologies (FET) programme, an international team of researchers (France, Sweden, Israel) has developed a new microfluidic set-up, where researchers can ‘bend matter’, enabling them to re-organise the colloidal droplet clusters used to fabricate the crystals into Tetris-like blocks. The clusters have sizes ranging between two to five monodispersed droplets with an average size of 400nm and are highly replicable. Using this technique allows researchers to easily construct […]
Sandia light mixer generates 11 colors simultaneously
Eurekalert June 28, 2018 An international team of researchers (USA – Sandia National Laboratories, Germany) has developed an optical mixer using an array of nanocylinders made from gallium arsenide laid out in a square pattern about 840 nanometers apart from one another. They selected two near infrared lasers with wavelengths tuned to the metamaterial’s resonant frequencies. The light from the two lasers — call them frequencies A and B — mix to produce 11 colors from different mixing products including A+A, A+B, B+B, A+A+B, and A+B+B, and so on. This was accomplished without the need to change angles or match […]