Phys.org November 26, 2024 Supraparticles comprising semiconductor colloidal quantum dots as building blocks are a new class of microscopic lasers with a wide host of applications. Despite the recent advances in their fabrication, there have been no reports of their quantum dot components being recovered for use in a circular economy. Researchers in the UK demonstrated a novel method for the recycling of whispering-gallery-mode supraparticle lasers with a quantum dot recovery yield of 85%. The photoluminescence quantum yield of the recycled quantum dots was retained at 83 ± 16% from the initial batch of 86 ± 9%. The recycled quantum […]
Tag Archives: Lasers
Engineering perovskite materials at the atomic level paves way for new lasers, LEDs
Phys.org October 11, 2024 Layered hybrid perovskites (LHPs) have emerged as promising reduced-dimensional semiconductors for next-generation photonic and energy applications where controlling the size, orientation, and distribution of quantum wells (QWs) is of paramount importance. A team of researchers in the US (North Carolina State University, Brookhaven National Laboratory) revealed that bulky molecular spacers act as crystal-terminating ligands to form colloidal nanoplatelets (NPLs) during early stages of LHP formation. They proved that NPLs ripen and grow, playing a decisive role in the time evolution of QW size, population distribution, and orientation. They demonstrated that antisolvent drip interrupts NPL ripening and […]
Researchers develop technology to mass produce quantum dot lasers for optical communications
Phys.org June 28, 2024 To produce 75 °C continuous-wave operation research in South Korea investigated InAs/GaAs quantum dot laser diodes (QDLDs) on a GaAs substrate grown by utilizing all-metalorganic chemical vapor deposition technology with a p-AlGaAs cladding layer. The InAs quantum dots (QDs) in a dot-in-a-well (DWELL) structure formed by engineering the strained bottom InGaAs layer were successfully grown without detectable clusters, making it possible to increase the number of DWELL stacks effectively. The results of electron-channeling contrast imaging revealed that dislocations in the p-cladding layer were generated due to the accumulative strain of the DWELL and low-temperature growth. The […]
Researchers develop laser that could ‘reshape the landscape of integrated photonics’
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 […]
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 […]