Researchers achieve extreme-ultraviolet spectral compression by four-wave mixing  January 25, 2021 Nonlinear optical techniques have made it possible to change the color of light and modify its spectral bandwidth without compromising the intensity. However, nonlinear optical techniques are not readily available in the XUV region of the electromagnetic spectrum. Researchers in Germany have demonstrated a concept for efficient spectral compression by four-wave mixing exploiting a phase-matching scheme based on closely spaced resonances. They compressed broadband radiation in the 145–130 nm wavelength range into a narrow-bandwidth XUV pulse at 100.3 nm wavelength in the presence of a broadband near-infrared pulse in a krypton gas jet. The narrowband XUV pulses has […]

Light from inside the tunnel

Nanowerk  June 30, 2020 In their experiment researchers in Germany focused two ultrashort light pulses with different wavelengths and slightly different propagation directions onto a thin slab of glass. A time- and frequency-resolved analysis of the emerging light emission showed that the current associated with the quantum mechanical tunneling process itself creates an optical non-linearity. The findings significantly expand both the fundamental understanding of optical non-linearity in dielectric materials and its potential for applications in information processing and light-based material processing…read more. TECHNICAL ARTICLE

Researchers catch light in a funnel  March 27, 2020 Rather than being an unavoidable nuisance, non-Hermiticity can be precisely controlled and used for sophisticated applications. Researchers in Germany implemented a non-Hermitian photonic mesh lattice by tailoring the anisotropy of the inter-site coupling. The appearance of an interface results in a complete collapse of the entire eigenmode spectrum, leading to an exponential localization of all modes at the interface. Consequently, any light field within the lattice travels toward this interface, irrespective of its shape and input position. Based on this topological phenomenon, they demonstrated a highly efficient funnel for light. The light accumulation achieved by the […]

New way to control the phase of light using 2D materials

Science Daily  February 24, 2020 Little is known about the effect of doping on the optical properties of TMDs at wavelengths far from excitonic resonances, where the material is transparent and therefore could be leveraged in photonic circuits. A team of researchers in the US (Columbia University, North Carolina State University, University of Chicago) has demonstrated the strong electro refractive response of monolayer tungsten disulfide (WS2) at near-infrared wavelengths (deep in the transparency regime) by integrating it on silicon nitride photonic structures to enhance the light–matter interaction with the monolayer. They showed that the doping-induced phase change relative to change […]

Nanoscale manipulation of light leads to exciting new advancement

Eurekalert  October 11, 2019 Researchers at the University of New Mexico studied arrays composed of silver nanoparticles placed in a repeating pattern. When the arrays are illuminated with light, each of the particles produces a strong response, which, in turn, results in enormous collective behaviors if all the particles can interact with one another. This happens at certain wavelengths of incident light, which are determined by the interparticle spacing of the array, and can result in electric fields that are thousands, or even tens of thousands, of times that of the light shined on the array. The strength of this […]

Light can scatter from light, CERN physicists confirm

Physics World  August 14, 2019 The quantum electrodynamic process of photon–photon scattering has for the first time been confirmed experimentally to a high degree of certainty. CERN’s ATLAS collaboration, which involves hundreds of physicists from around the world, made the breakthrough after analysing a large dataset of candidate scattering events using a neural network. Their discovery could fuel new research into a variety of theories beyond the Standard Model of particle physics. The discoveries of the ATLAS collaboration could inform future studies aiming to confirm and constrain these theories, potentially allowing much-anticipated updates to the Standard Model…read more. Open Access […]

Light may increase magnetic memory speeds 1000 times, decrease electricity consumption  July 11, 2019 To reduce energy consumption in magnetic memory devices and improve their speeds, a team of researchers in the US (NIST, University of Colorado, University of Oregon) has developed a method that uses optics through localized surface plasmon resonances to couple light to nanomagnets and produce faster spintronic devices switching speeds and potential lower energy consumption. The method could ultimately lead to memory writing speeds that are 1,000 times faster than current ones…read more. TECHNICAL ARTICLE 

How to bend waves to arrive at the right place

Science Daily  June 24, 2019 Electronic matter waves traveling through the weak and smoothly varying disorder potential of a semiconductor show a characteristic branching behavior instead of a smooth spreading of flow. By transferring this phenomenon to optics, researchers at Harvard University demonstrated numerically, how the branched flow of light can be controlled to propagate along a single branch rather than along many of them at the same time. The method is based on shaping the incoming wavefront and only requires partial knowledge of the system’s transmission matrix. They show that the light flowing along a single branch has a […]

Graphene sets a new record on squeezing light to one atom

Science Daily  April 20, 2018 An international team of researchers (Spain, France, Portugal, USA – MIT) has shown that a graphene-insulator-metal heterostructure can overcome energy loss and demonstrate plasmon confinement down to the ultimate limit of the length scale of one atom. This is achieved through far-field excitation of plasmon modes squeezed into an atomically thin hexagonal boron nitride dielectric spacer between graphene and metal rods. A theoretical model that takes into account the nonlocal optical response of both graphene and metal is used to describe the results. These ultraconfined plasmonic modes, addressed with far-field light excitation, enable a route […]

Generating energy from fluctuations of light  March 27, 2018 Researchers in Sweden have developed a method and a material that generates an electrical impulse when the light fluctuates from sunshine to shade and vice versa. They created a tiny optical generator by combining the small antennas consisting gold nanodiscs placed on a substrate and coated with a polymeric film to create the pyroelectric properties. The antennas generate heat that is then converted to electricity with the aid of the polymer. The degree of polarisation of the polymer affects the magnitude of the generated power, while the thickness not to have any effect at all. Applications […]