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We study the low-energy conductivity dynamics after femtosecond perturbation of the stripe-ordered phase in a strongly-correlated nickelate. The experiments reveal ultrafast suppression and recovery of electron-phonon coupling that tracks the atomic-scale localization of correlated charges.
We track the collective terahertz free-carrier response of 1T-TiSe2 during femtosecond photo-induced melting and recovery of a charge density wave. The formation of charge order is highly sensitive to the transient excess carrier density, suggesting a strong excitonic influence.
We investigate deformations of fluid interfaces caused by small (∼nN) optical force of a low power laser beam under total-internal-reflection. For air-water interface deformations are undetectable, unlike recently claimed in ref. [3]. Using a critical fluid-fluid interface having weak surface tension large fluid-lens effects in the form of a bump are seen. Our observations support standard optofluidic...
We show theoretically that large modulation of the amplitude and phase of mid-infrared light can be achieved by dynamically shifting the resonance of graphene-metal plasmonic antennas via electrical tuning of the optical conductivity of graphene.
By leveraging the polarization-dependence of the Bloch-surface-wave-induced giant Goos-Hanchen shift, a novel polarization-modulation-based GH sensing scheme is demonstrated, which can suppress the common mode drift in the setup to ensure better system stability.
We demonstrate substrate-transferred crystalline coatings, based on epitaxial Bragg mirrors directly-bonded to fused silica, exhibiting an unprecedented tenfold reduction in Brownian noise. These mirrors promise a significant advancement in the performance of precision optical interferometers.
Plasmonics is an exploding new field of science and technology in which the flow of light can be molded at the nanoscale using metallic nanostructures. This newly found ability is rapidly impacting every facet of optics and photonics and is enabling a myriad of exciting new technologies. Semiconductor nanophotonics has also seen tremendous recent progress in the development of high performance light...
A multilayer dielectric coating deposited on the endface of a single-mode fiber is used as an optical sensor for high pressures. The reflectance of the coating decreases by 10% for a pressure of 710 MPa.
Nanostructured polymer surfaces with optical functionality are fabricated by up-scalable methods, nanoimprinting and injection moulding. The fabrication and performance of nanostructured polymer surfaces with anti-reflective functionality are discussed.
We report on our research in power scaling OPSL around 1μm to exceed 100W per chip by combining a rigorous quantum design of an optimized MQW epitaxial structure, highly accurate and reproducible wafer growth and an efficient thermal management strategy. Recently, we have utilized these state-of-the-art optimized OPSL chips to achieve a new record single frequency output power of 15W. The highly coherent...
An interferogram from a two-staged optical low-coherence Mach-Zehnder interferometer is demonstrated to double the sensitivity improvement for fiber strain sensing using the fiber Bragg grating based optical ruler through its narrow linewidth reflection spectrum.
We present an experimental demonstration of an optical metamaterial with a nearly isotropic low-index response, leading to angular selectivity of transmission and enhanced directive emission from quantum dots placed within the metamaterial.
We demonstrate multi-color DFB QCLs with separated electrical pumping for independent single-mode emission of several wavelengths from the same ridge. This will be implemented in our mid-infrared spectroscopy sensors for gases (CO2) and liquids (cocaine).
The quantum cascade laser, operates over an extremely wide wavelength range in the mid-infrared with high output power and low power consumption (<1W). A new generation of devices show enhanced wavelength multiplexing and tuning agility capabilities as well a frequency comb generation over more than 100cm−1.
We demonstrate the creation of a vortex beam by using a GaAs-based ring-shape Bragg reflector waveguide functioning as an angular diffraction element. A tunable ring-far field patterns can be clearly shown with wavelength tuning.
We present a new method for sensitive ultrasound detection using an open-cavity optoacoustic sensor. Our results have demonstrated significant enhancement of detection sensitivity when the open-cavity sensor is used in media with large isothermal compressibility.
The NIF laser pulse used for ignition experiments is tuned by direct observation of the shocks launched into the capsule during the initial phases of the pulse. Optical velocimetry is key to this task.
An imaging technique is presented that enables monitoring of the wet thermal oxidation of a thin AlAs layer embedded between two distributed Bragg reflector mirrors in a micropillar. After oxidation we confirm by white light reflection spectroscopy that high quality optical modes confined to a small volume have been formed. The combination of these two optical techniques provides a reliable and efficient...
We demonstrate a commercialization-ready metrology tool for electrical, optical, and thermal characterization of operating optoelectronic devices, with a spatial resolution of 250nm. Applications are demonstrated to a wide range of electrical and photonic devices.
We show, theoretically and experimentally, that the polarization of high-order harmonics driven by counter-rotating elliptically-polarized bichromatic lasers are completely controllable: from linear through elliptic to circular polarization. New selection rules are observed.
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