Phys.org October 24, 2022 A team of researchers in the US (University of Rochester, UC Santa Barbara, Caltech, Clemson University) has developed multi-color integrated laser that emits high-coherence light at telecommunication wavelengths allows laser-frequency tuning at record speeds and can be configured at the visible band. Using a hybrid integrated III-V/Lithium Niobate structure they demonstrated several essential capabilities that have not existed in previous integrated lasers. These include a record-high frequency modulation speed of 2 exahertz/s and fast switching at 50 MHz, both of which are made possible by integration of the electro-optic effect. The device co-lases at infrared and […]
Tag Archives: Lasers
Exploring quantum electron highways with laser light
Nanowerk August 18, 2022 The phase transition between non-trivial and trivial topological states is important for next-generation technology, such as dissipation-free electronics. A team of researchers in the US (SLAC National Accelerator Laboratory, Stanford University, Harvard University, the State University of New Jersey) has demonstrated that circularly polarized laser-field-driven high-harmonic generation is distinctly sensitive to the non-trivial and trivial topological phases in the prototypical three-dimensional topological insulator bismuth selenide. The phase transition is chemically initiated by reducing the spin–orbit interaction strength through the substitution of bismuth with indium atoms. The phase transition is chemically initiated by reducing the spin–orbit interaction […]
It’s a trap! Laser light ensnared by invisible bonds
Science Daily June 1, 2022 Anderson localization predicts that transport in one-dimensional uncorrelated disordered systems comes to a complete halt, experiencing no transport whatsoever. However, a disordered physical system is always correlated because it must have a finite spectrum. Localization is dominant only for wave packets whose spectral extent resides within the region of the wave number span of the disorder. An international team of researchers (Israel, Germany, Spain) has experimentally shown that Anderson localization can occur and even be dominant for wave packets residing entirely outside the spectral extent of the disorder. The team studied the evolution of wave […]
Breakthrough for efficient and high-speed spintronic devices
Science Daily April 25, 2022 How the spin evolves in the nanoworld on extremely short time scales, in one millionth of one billionth of a second, has remained largely mysterious. An international team of researchers (Austria, Canada, Germany, Switzerland, France, China) used a tabletop ultrafast soft X-ray microscope based on a high-energy Ytterbium laser to spatio-temporally resolve the spin dynamics inside rare earth materials. They recorded a series of snapshot images of the nanoscale rare earth magnetic structures providing rich information on the magnetic properties that are as accurate as those obtained using large-scale X-ray facilities. According to the researchers […]
Lasers trigger magnetism in atomically thin quantum materials
Science Daily April 20, 2022 Recently two-dimensional moiré superlattices have emerged as a promising platform for quantum engineering. The power of the moiré system lies in the high tunability of its physical parameters by adjusting the layer twist angle, electrical field, moiré carrier filling and interlayer coupling. An international team of researchers (USA – University of Washington, Oak Ridge National Laboratory, Pacific Northwest National Laboratory, Hong Kong, Japan) found that optical excitation can highly tune the spin–spin interactions between moiré-trapped carriers, resulting in ferromagnetic order in WS2 /WSe2 moiré superlattices. Near the filling factor of −1/3, as the excitation power […]
The perfect trap: a new way to control the polarization of light
Phys.org January 19, 2022 An international team of researchers (Germany, UK, Scotland, Switzerland) has demonstrated that the Kerr effect in a high-finesse Fabry-Pérot resonator can be utilized to control the polarization of a continuous wave laser. They showed that a linearly polarized input field is converted into a left- or right-circularly-polarized field, controlled via the optical power. The observations are explained by Kerr-nonlinearity induced symmetry breaking, which splits the resonance frequencies of degenerate modes with opposite polarization handedness in an otherwise symmetric resonator. According to the researchers in the future one could arrange many of these devices onto a photonic […]
Minimizing laser phase noise with machine learning
Phys.org January 3, 2022 One way of getting closer to an ultra-precise laser is to determine the phase noise and compensate for it. Researchers in Denmark have developed an algorithm that can analyze and find laser light patterns using machine learning, where a model for the noise is constantly being improved. On this basis they hope to develop a form of intelligent filter that continuously cleans the laser beam of noise. They were able to measure the noise up to very high frequencies, and the results contradicted the established understanding of laser noise. With the more detailed knowledge of the […]
Cracking open strong field quantum electrodynamics
Phys.org September 28, 2021 After theoretical and computer modeling studies an international team of researchers (France, USA – Lawrence Livermore National Laboratory) proposed a scheme to explore regimes of strong-field quantum electrodynamics (SF QED) otherwise unattainable with the currently available laser technology. The scheme relies on relativistic plasma mirrors curved by radiation pressure to boost the intensity of petawatt-class laser pulses by Doppler effect and focus them to extreme field intensities. They showed that very clear SF QED signatures could be observed by placing a secondary target where the boosted beam is focused. This may finally crack the elusive physics […]
Tiny lasers acting together as one: Topological vertical cavity laser arrays
Phys.org September 24, 2021 Vertical-Cavity Surface-Emitting Lasers (VCSEL) device has miniscule size of only a few microns, which sets a stringent limit on the output power it can generate. An international team of researchers (Israel, Germany) utilized the concepts of topological photonics with VCSELs that emit light vertically, while the topological process responsible for the mutual coherence and locking of the VCSELs occurs in the plane of the chip. It resulted in a powerful but very compact and efficient laser, not limited by a number of VCSEL emitters, and undisturbed by defects or altering temperatures. The topological principle of this […]
Electrons in quantum liquid gain energy from laser pulses
Phys.org July 13, 2021 Laser-assisted electron scattering (LAES), a light–matter interaction process that facilitates energy transfer between strong light fields and free electrons, has so far been observed only in gas phase. An international team of researchers (Austria, Japan) has detected LAES at condensed phase particle densities, for which they created nano-structured systems consisting of a single atom or molecule surrounded by a superfluid He shell of variable thickness. They observed that free electrons, generated by femtosecond strong-field ionization of the core particle, can gain several tens of photon energies due to multiple LAES processes within the liquid He shell. […]