Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Continuous-wave phase-matched molecular optical modulator.

ABSTRACT: In optical modulation, the highest available modulation rate is basically limited to the GHz frequency range at best. This is because optical modulation is often performed using electro-optic or acousto-optic effects that require application of an external signal to solid-state nonlinear optical materials. Here we describe optical modulation of continuous-wave radiation at frequencies exceeding 10 THz based on ultrafast variation of molecule polarizability arising from coherent molecular motion. The optical modulation efficiency is extensively enhanced by fulfilling phase-matching conditions with the help of dispersion control of the optical cavity, generating sidebands with a highest ratio of 7.3 × 10(-3). These results will pave the way for development of versatile optical modulation-based techniques in a wide range of research fields in optical sciences, such as mode-locked lasers operating in the THz range.

SUBMITTER: Zaitsu S

PROVIDER: S-EPMC4757869 | biostudies-other | 2016

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

Tunable continuous wave emission via phase-matched second harmonic generation in a ZnSe microcylindrical resonator.

Project description:Whispering gallery mode microresonators made from crystalline materials are of great interest for studies of low threshold nonlinear phenomena. Compared to amorphous materials, crystalline structures often exhibit desirable properties such as high indices of refraction, high nonlinearities, and large windows of transparency, making them ideal for use in frequency comb generation, microlasing and all-optical processing. In particular, crystalline materials can also possess a non-centrosymmetric structure which gives rise to the second order nonlinearity, necessary for three photon processes such as frequency doubling and parametric down-conversion. Here we report a novel route to fabricating crystalline zinc selenide microcylindrical resonators from our semiconductor fibre platform and demonstrate their use for tunable, low power continuous wave second harmonic generation. Visible red light is observed when pumped with a telecommunications band source by a process that is phase-matched between different higher order radial modes, possible due to the good spatial overlap between the pump and signal in the small volume resonator. By exploiting the geometrical flexibility offered by the fibre platform together with the ultra-wide 500-22000 nm transmission window of the ZnSe material, we expect these resonators to find use in applications ranging from spectroscopy to quantum information systems.

| S-EPMC4488835 | biostudies-literature

Ultralow-phase-noise millimetre-wave signal generator assisted with an electro-optics-modulator-based optical frequency comb.

Project description:Low-noise millimetre-wave signals are valuable for digital sampling systems, arbitrary waveform generation for ultra-wideband communications, and coherent radar systems. However, the phase noise of widely used conventional signal generators (SGs) will increase as the millimetre-wave frequency increases. Our goal has been to improve commercially available SGs so that they provide a low-phase-noise millimetre-wave signal with assistance from an electro-optics-modulator-based optical frequency comb (EOM-OFC). Here, we show that the phase noise can be greatly reduced by bridging the vast frequency difference between the gigahertz and terahertz ranges with an EOM-OFC. The EOM-OFC serves as a liaison that magnifies the phase noise of the SG. With the EOM-OFC used as a phase noise "booster" for a millimetre-wave signal, the phase noise of widely used SGs can be reduced at an arbitrary frequency f (6???f???72?GHz).

| S-EPMC4869108 | biostudies-literature

High-power continuous-wave optical waveguiding in a silica micro/nanofibre.

Project description:As miniature fibre-optic platforms, micro/nanofibres (MNFs) taper-drawn from silica fibres have been widely studied for applications from optical sensing, nonlinear optics to optomechanics and atom optics. While continuous-wave (CW) optical waveguiding is frequently adopted, so far almost all MNFs are operated in low-power region (e.g., <0.1 W). Here, we demonstrate high-power low-loss CW optical waveguiding in MNFs around 1550-nm wavelength. We show that a pristine MNF, even with a diameter down to 410 nm, can waveguide an optical power higher than 10 W, which is about 30 times higher than demonstrated previously. Also, we predict an optical damage threshold of 70 W. In high-power CW waveguiding MNFs, we demonstrate high-speed optomechanical driving of microparticles in air, and second harmonic generation efficiency higher than those pumped by short pulses. Our results may pave a way towards high-power MNF optics, for both scientific research and technological applications.

| S-EPMC10082085 | biostudies-literature

Continuous wave amplified spontaneous emission in phase-stable lead halide perovskites.

Project description:Sustained stimulated emission under continuous-wave (CW) excitation is a prerequisite for new semiconductor materials being developed for laser gain media. Although hybrid organic-inorganic lead-halide perovskites have attracted much attention as optical gain media, the demonstration of room-temperature CW lasing has still not been realized. Here, we present a critical step towards this goal by demonstrating CW amplified spontaneous emission (ASE) in a phase-stable perovskite at temperatures up to 120 K. The phase-stable perovskite maintains its room-temperature phase while undergoing cryogenic cooling and can potentially support CW lasing also at higher temperatures. We find the threshold level for CW ASE to be 387 W cm-2 at 80 K. These results indicate that easily-fabricated single-phase perovskite thin films can sustain CW stimulated emission, potential at higher temperatures as well, by further optimization of the material quality in order to extend the carrier lifetimes.

| S-EPMC6395683 | biostudies-literature

Continuous volumetric imaging via an optical phase-locked ultrasound lens.

Project description:In vivo imaging at high spatiotemporal resolution is key to the understanding of complex biological systems. We integrated an optical phase-locked ultrasound lens into a two-photon fluorescence microscope and achieved microsecond-scale axial scanning, thus enabling volumetric imaging at tens of hertz. We applied this system to multicolor volumetric imaging of processes sensitive to motion artifacts, including calcium dynamics in behaving mouse brain and transient morphology changes and trafficking of immune cells.

| S-EPMC4551496 | biostudies-literature

Tailored Multi-Color Dispersive Wave Formation in Quasi-Phase-Matched Exposed Core Fibers.

Project description:Widely wavelength-tunable femtosecond light sources in a compact, robust footprint play a central role in many prolific research fields and technologies, including medical diagnostics, biophotonics, and metrology. Fiber lasers are on the verge in the development of such sources, yet widespan spectral tunability of femtosecond pulses remains a pivotal challenge. Dispersive wave generation, also known as Cherenkov radiation, offers untapped potentials to serve these demands. In this work, the concept of quasi-phase matching for multi-order dispersive wave formation with record-high spectral fidelity and femtosecond durations is exploited in selected, partially conventionally unreachable spectral regions. Versatile patterned sputtering is utilized to realize height-modulated high-index nano-films on exposed fiber cores to alter fiber dispersion to an unprecedented degree through spatially localized, induced resonances. Nonlinear optical experiments and simulations, as well as phase-mismatching considerations based on an effective dispersion, confirm the conversion process and reveal unique emission features, such as almost power-independent wavelength stability and femtosecond duration. This resonance-empowered approach is applicable to both fiber and on-chip photonic systems and paves the way to instrumentalize dispersive wave generation as a unique tool for efficient, coherent femtosecond multi-frequency conversion for applications in areas such as bioanalytics, life science, quantum technology, or metrology.

| S-EPMC8922130 | biostudies-literature

Enhancement of Photoacoustic Signal Strength with Continuous Wave Optical Pre-Illumination: A Non-Invasive Technique.

Project description:Use of portable and affordable pulse light sources (light emitting diodes (LED) and laser diodes) for tissue illumination offers an opportunity to accelerate the clinical translation of photoacoustic imaging (PAI) technology. However, imaging depth in this case is limited because of low output (optical) power of these light sources. In this work, we developed a noninvasive technique for enhancing strength (amplitude) of photoacoustic (PA) signal. This is a photothermal-based technique in which a continuous wave (CW) optical beam, in addition to short-pulse ~ nsec laser beam, is employed to irradiate and, thus, raise the temperature of sample material selectively over a pre-specified region of interest (we call the process as pre-illumination). The increase in temperature, in turn enhances the PA-signal strength. Experiments were conducted in methylene blue, which is one of the commonly used contrast agents in laboratory research studies, to validate change in temperature and subsequent enhancement of PA-signal strength for the following cases: (1) concentration or optical absorption coefficient of sample, (2) optical power of CW-optical beam, and (3) time duration of pre-illumination. A theoretical hypothesis, being validated by numerical simulation, is presented. To validate the proposed technique for clinical and/or pre-clinical applications (diagnosis and treatments of cancer, pressure ulcers, and minimally invasive procedures including vascular access and fetal surgery), experiments were conducted in tissue-mimicking Agar phantom and ex-vivo animal tissue (chicken breast). Results demonstrate that pre-illumination significantly enhances PA-signal strength (up to ~70% (methylene blue), ~48% (Agar phantom), and ~40% (chicken tissue)). The proposed technique addresses one of the primary challenges in the clinical translation of LED-based PAI systems (more specifically, to obtain a detectable PA-signal from deep-seated tissue targets).

| S-EPMC7914629 | biostudies-literature

Optofluidic variable optical path modulator.

Project description:The optofluidic devices including optofluidic lens, optical switch and liquid prism have found widespread applications in imaging, optical communication and lighting. Here, we report a novel optofluidic device called optofluidic variable optical path modulator. Our proposed modulator consists of two main chambers. The two chambers are connected by two tubes to form a closed-loop fluidic system. Two immiscible liquids are filled into the two chambers and form two L-L interfaces. A transparent sheet is placed between one L-L interface to get flat interface. When a voltage is applied on the device, the flat interface can move up and down. Thus, variable optical path can be obtained by applying a voltage. To prove the concept, we fabricate an optofluidic device whose largest movable distance of L-L interface is ~7.5?mm and the optical path length change is ~1.15?mm. The proposed optofluidic device has potential applications in imaging, adaptive optics, optical detection and so on.

| S-EPMC6506494 | biostudies-literature

Optical coherence tomography-guided laser microsurgery for blood coagulation with continuous-wave laser diode.

Project description:Blood coagulation is the clotting and subsequent dissolution of the clot following repair to the damaged tissue. However, inducing blood coagulation is difficult for some patients with homeostasis dysfunction or during surgery. In this study, we proposed a method to develop an integrated system that combines optical coherence tomography (OCT) and laser microsurgery for blood coagulation. Also, an algorithm for positioning of the treatment location from OCT images was developed. With OCT scanning, 2D/3D OCT images and angiography of tissue can be obtained simultaneously, enabling to noninvasively reconstruct the morphological and microvascular structures for real-time monitoring of changes in biological tissues during laser microsurgery. Instead of high-cost pulsed lasers, continuous-wave laser diodes (CW-LDs) with the central wavelengths of 450 nm and 532 nm are used for blood coagulation, corresponding to higher absorption coefficients of oxyhemoglobin and deoxyhemoglobin. Experimental results showed that the location of laser exposure can be accurately controlled with the proposed approach of imaging-based feedback positioning. Moreover, blood coagulation can be efficiently induced by CW-LDs and the coagulation process can be monitored in real-time with OCT. This technology enables to potentially provide accurate positioning for laser microsurgery and control the laser exposure to avoid extra damage by real-time OCT imaging.

| S-EPMC4645164 | biostudies-other

Low-threshold room-temperature continuous-wave optical lasing of single-crystalline perovskite in a distributed reflector microcavity.

Project description:Organic-inorganic halide perovskites have achieved remarkable success in various optoelectronic devices. A high-quality CH3NH3PbBr3 single-crystalline thin film has been directly grown in a micrometer gap between a pair of distributed reflectors with over 99.9% reflectivity, which naturally form a vertical cavity surface-emitting laser device with a single mode or several modes. The single-crystalline perovskite has an exciton lifetime of 426 ns and evidence of the exciton-photon coupling is observed. At room temperature and under continuous-wave optical pumping conditions, this device lases at a threshold of 34 mW cm-2 in the green gap. The extremely low lasing threshold suggests that polariton lasing may occur in the strongly confined optical cavity comprising the high-quality single-crystalline perovskite.

| S-EPMC9074939 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data