A5090404472- Transition Metal Oxide Nanomaterials
- Nonlinear Optical Materials Studies
- Gold and Silver Nanoparticles Synthesis and Applications
- Laser Material Processing Techniques
- Laser-Matter Interactions and Applications
- Laser-Ablation Synthesis of Nanoparticles
- Plasmonic and Surface Plasmon Research
- Advanced Memory and Neural Computing
- Laser Design and Applications
- Photonic and Optical Devices
- Ga2O3 and related materials
- Phase-change materials and chalcogenides
- Laser-induced spectroscopy and plasma
- Optical Wireless Communication Technologies
- Advanced Electron Microscopy Techniques and Applications
- Advanced X-ray Imaging Techniques
- Metamaterials and Metasurfaces Applications
- Near-Field Optical Microscopy
- Semiconductor Lasers and Optical Devices
- Optical Coatings and Gratings
- Solid State Laser Technologies
- Electronic and Structural Properties of Oxides
- Optical and Acousto-Optic Technologies
- Advanced Optical Imaging Technologies
- Mormonism, Religion, and History
Vanderbilt University
2002-2024
W. M. Keck Foundation
2008
Center for Nanoscale Science and Technology
2006
Optical phase change materials (O-PCMs) are being explored for a variety of photonic applications due to the extraordinarily large changes in optical properties that occur during electronic and/or structural transitions. Here, recent work integrating O-PCMs integrated silicon devices is presented. Conceptually proposed and experimentally realized thermo-optic, electro-optic, all-optical Si/O-PCM described perspectives on potential electro-optic modulators outlined.
Optical limiting is desirable or necessary in a variety of applications that employ high-power light sources sensitive photodetectors. However, the most prevalent methods compromise between on-state transmission and turndown ratio rely on narrow windows. We demonstrate metasurface-based architecture incorporating phase-change materials enables both high broadband (-4.8 dB) while also providing large (25.2 dB). Additionally, this design can be extended for multiwavelength due to off-resonance...
Using light to control transient phases in quantum materials is an emerging route engineer new properties and functionality, with both thermal non-thermal observed out of equilibrium. Transient are expected be heterogeneous, either through photo-generated domain growth or by generating topological defects, this impacts the dynamics system. However, nanoscale heterogeneity has not been directly observed. Here we use time- spectrally resolved coherent X-ray imaging track prototypical induced...
Abstract A growing class of nonlinear materials employ the localized surface plasmonic resonance (LSPR) nanoparticles to enhance harmonic generation. Material systems containing harmonically coupled metallic and semiconductor have been shown further increase performance. Here, we explore effect dual interactions in bilayer CuS Au nanoparticle films on third generation (THG). Detuning LSPR away from excitation frequency changes dominant upconversion pathway THG multiple photon...
Reconfigurable optical systems are the object of continuing, intensive research activities, as they hold great promise for realizing a new generation compact, miniaturized, and flexible devices. However, current reconfigurable often tune only single state variable triggered by an external stimulus, thus, leaving out many potential applications. Here we demonstrate multistate system enabled phase transitions in vanadium dioxide (VO2). By controlling phase-transition characteristics VO2 with...
Ultrafast phase transitions induced by femtosecond light pulses present a new opportunity for manipulating the properties of materials. Understanding how these transient states are different from, or similar to, their thermal counterparts is key to determining materials can exhibit that not found in equilibrium. In this paper, we reexamine case light-induced insulator-metal transition prototypical, strongly correlated material VO$_2$, which nonthermal Mott-Hubbard has been claimed. Here,...
Abstract Hybrid material systems are a promising approach for extending the capabilities of silicon photonics. Given weak electro‐optic and thermo‐optic effects in silicon, there is intense interest integrating an ultrafast‐switching phase‐change with large refractive index contrast into waveguide, such as vanadium dioxide (VO 2 ). It well established that phase transition VO thin films can be triggered by ultrafast, 800 nm laser pulses, pump‐laser fluence critical determinant recovery time...
Dual heterostructures integrating noble-metal and copper chalcogenide nanoparticles have attracted a great deal of attention in nonlinear optics, because coupling their localized surface plasmon resonances (LSPRs) substantially enhances light–matter interactions through local-field effects. Previously, enhanced cascaded third-harmonic generation was demonstrated Au/CuS mediated by harmonically coupled resonances. This suggests promising approach for extending enhancement to higher harmonics...
Phase coexistence during a solid-to-solid transition in quantum material is measured using x-ray coherent diffractive imaging.
As laser micromachining is applied to ever smaller structures and more complex materials, the demand for greater control of energy budget, in space time, grows commensurately. Here we describe materials modification using picosecond resonant excitation mid-infrared spectral region create spatially temporally dense vibrational, rather than electronic, excitation. Examples include ablation fused silica machining crystalline quartz; deposition functionalized polymers on microstructures,...
Vapor-phase transport is a rapid, inexpensive method of growing nano- and microscale single crystals vanadium dioxide, correlated-electron material with metal–insulator transition at ∼70 °C. Many growth parameters—including time, temperature, precursor, ambient conditions, substrate—have been explored, variety crystal morphologies has produced, most emphasis given to oriented nanowires. However, comprehensive strategy for predicting/controlling the morphology still evolving. Here, we...
Heterostructures combining two or more metal and/or semiconductor nanoparticles exhibit enhanced upconversion arising from localized surface plasmon resonances (LSPRs). However, coupled plasmon-exciton systems are slowed by excitonic relaxation and metallic multi-plasmon not broadly tunable. Here, we describe a heterostructure in which insulating alumina layers vary separation between CuS Au nanoparticles, allowing experimental confirmation of the d^(-6) dependence typical surface-dipole...
We report the successful fabrication of layers functionalized nanoparticles using a novel infrared, laser-based deposition technique. A frozen suspension was ablated with laser tuned to vibrational mode solvent, resulting in disruption matrix and ejection nanoparticles. The solvent pumped away collected by receiving substrate conformal process. Photoluminescence measurements containing two common dyes showed no significant change emission properties either dye, suggesting that damage...
Recent market developments in electronic and opto-electronic devices based on small organic molecules polymers is driving the search for a variety of new processing tools thin-film deposition. In this paper, we describe vacuum-phase deposition technique — resonant infrared pulsed laser that true vapor phase thermally labile or photochemically sensitive organics polymers. Several examples deposition, including structural, insulating conducting polymers, are presented. Specifications...
In the version of this article initially published, y-axis range violin plots in Fig. 4a, now spanning between 0.0 and 1.0, spanned 0.2 1.0.Furthermore, leftmost panel, titled "Coupled Map Lattice (CML)," labels colours for five distributions dynamical regimes coupled map lattices were misplaced, which caused them to appear shuffled not agreement with main text results from 3a.
Nonlinear optical materials comprising metal nanocrystallites embedded in linear and nonlinear dielectrics are of wide current interest for use all-optical switching devices. We have investigated several ways which laser- ion-beam processing can be used to create vertically and/or laterally patterned nanostructured composite materials. Pulsed laser deposition using both dielectric targets layered structures some layers contain quantum dots as a element. Ion beams also induce the formation...
This Optical Materials Express feature issue presents a collection of twelve papers clustered around the general topic optical phase-change materials.While scientific study materials has long history, interest in these for as well electronic applications risen sharply last decade, and is now subject intense world-wide research efforts.In this set papers, topics range from basic studies to metasurfaces, sensing, integrated optics, silicon photonics polarization switching.
All-optical modulators are likely to play an important role in future chip-scale information processing systems. In this work, through simulations, we investigate the potential of a recently reported vanadium dioxide (VO<sub>2</sub>) embedded silicon waveguide structure for ultrafast all-optical signal modulation. With VO<sub>2</sub> length only 200 nm, finite-differencetime- domain simulations suggest broadband (200 nm) operation with modulation greater than 12 dB and insertion loss less 3...
Ultrashort laser pulses interacting with brittle dielectrics in the mid-infrared region of spectrum produce a number novel effects which are potentially useful materials processing and analysis. These include texturing surface, generation hydrodynamic instabilities, surprisingly efficient gentle ablation behavior. Nevertheless, mechanism infrared remains somewhat mysterious. Here we present evidence for explosive vaporization fused silica, initiated by picosecond from tunable free-electron...
Modulation of metamaterials in the near-infrared regime is limited by availability efficient reconfigurable materials at high frequencies. Here we demonstrate a metasurface that minimizes power requirements and enhances switching speed placing thin nanodisks vanadium dioxide (VO2) phase-change material feed gaps an array bow-tie field antennas. The device tunableover 360 nm near infrared exhibits modulation depth 33% resonant wavelength. employs integrated local heating to drive...
We present experimental results from second-harmonic generation studies of lithographically-prepared arrays centrosymmetric gold nanorods, extending a previous treatment. The serve as diffraction gratings, allowing control over the emission directions. intrinsic radiation patterns nanoparticles are superimposed on pattern, creating unique angular distribution light. surface plasmon resonance mode particles is tuned to match wavelength ultrafast Ti:sapphire excitation laser, dramatically...