scholarly journals Plasmonic nanostructures for shrinking structured light to access forbidden transitions

Nanophotonics ◽  
2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Kyosuke Sakai ◽  
Hiroki Kitajima ◽  
Keiji Sasaki
Keyword(s):  
Near Infrared ◽  
Strong Field ◽  
Structured Light ◽  
Plasmonic Nanostructures ◽  
Light Sources ◽  
Combined System ◽  
Quadrupole Field ◽  
Array Architecture ◽  
Forbidden Transitions ◽  
Tetramer Structure

Abstract Plasmonic nanostructures have considerable applicability in light–matter interactions owing to their capacity for strong field confinement and enhancement. Nanogap structures allow us to tailor electric field distributions at the nanoscale, bridging the differences in size and shape of atomic and light structures. In this study, we demonstrated that a plasmonic tetramer structure can squeeze structured light into a nanoscale area, in which a strong field gradient allows access to forbidden transitions. Numerical simulations showed that the gold tetramer structure on a glass substrate possesses a plasmonic eigenmode, which forms structured light with a quadrupole profile in the nanogap region at the center of the tetramer. The top–down technique employed using electron-beam lithography allows us to produce a gap size of approximately 50 nm, which supports plasmonic resonance in the near-infrared regime. In addition, we demonstrated an array architecture in which a collective lattice resonance enhances the intensity of the quadrupole field in multiple lattice units. This study highlights the possibility of accessing multipolar transitions in a combined system of structured light and plasmonic nanostructures. Our findings may lead to new platforms for spectroscopy, sensing, and light sources that take advantage of the full electronic spectrum of an emitter.

scholarly journals Metal–dielectric hybrid nanoantennas for efficient frequency conversion at the anapole mode

2018 ◽  
Vol 9 ◽  
pp. 2306-2314 ◽  
Author(s):  
Valerio F Gili ◽  
Lavinia Ghirardini ◽  
Davide Rocco ◽  
Giuseppe Marino ◽  
Ivan Favero ◽  
...  
Keyword(s):  
Frequency Conversion ◽  
Near Infrared ◽  
Strong Field ◽  
Second Harmonic ◽  
Near Field ◽  
Field Enhancement ◽  
High Refractive Index ◽  
Plasmonic Nanostructures ◽  
Ohmic Losses ◽  
Order Of Magnitude

Background: Dielectric nanoantennas have recently emerged as an alternative solution to plasmonics for nonlinear light manipulation at the nanoscale, thanks to the magnetic and electric resonances, the strong nonlinearities, and the low ohmic losses characterizing high refractive-index materials in the visible/near-infrared (NIR) region of the spectrum. In this frame, AlGaAs nanoantennas demonstrated to be extremely efficient sources of second harmonic radiation. In particular, the nonlinear polarization of an optical system pumped at the anapole mode can be potentially boosted, due to both the strong dip in the scattering spectrum and the near-field enhancement, which are characteristic of this mode. Plasmonic nanostructures, on the other hand, remain the most promising solution to achieve strong local field confinement, especially in the NIR, where metals such as gold display relatively low losses. Results: We present a nonlinear hybrid antenna based on an AlGaAs nanopillar surrounded by a gold ring, which merges in a single platform the strong field confinement typically produced by plasmonic antennas with the high nonlinearity and low loss characteristics of dielectric nanoantennas. This platform allows enhancing the coupling of light to the nanopillar at coincidence with the anapole mode, hence boosting both second- and third-harmonic generation conversion efficiencies. More than one order of magnitude enhancement factors are measured for both processes with respect to the isolated structure. Conclusion: The present results reveal the possibility to achieve tuneable metamixers and higher resolution in nonlinear sensing and spectroscopy, by means of improved both pump coupling and emission efficiency due to the excitation of the anapole mode enhanced by the plasmonic nanoantenna.

scholarly journals Single-shot imaging of surface molecular ionization in nanosystems

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Fenghao Sun ◽  
Hui Li ◽  
Shanshan Song ◽  
Fei Chen ◽  
Jiawei Wang ◽  
...  
Keyword(s):  
Near Infrared ◽  
Strong Field ◽  
Imaging Technique ◽  
Near Field ◽  
Velocity Map Imaging ◽  
Single Shot ◽  
Surface Molecules ◽  
Nanoparticle Interactions ◽  
Field Response ◽  
Ion Species

Abstract Using single-shot velocity map imaging technique, explosion imaging of different ion species ejected from 50 nm SiO2 nanoparticles are obtained excitedly by strong near-infrared and ultraviolet femtosecond laser fields. Characteristic momentum distributions showing forward emission of the ions at low excitation intensities and shock wave behaviors at high intensities are observed. When the excitation intensity is close to the dissociative ionization threshold of the surface molecules, the resulting ion products can be used to image the instant near-field distributions. The underlying dynamics of shock formation are simulated by using a Coulomb explosion model. Our results allow one to distinguish the ultrafast strong-field response of various molecular species in nanosystems and will open a new way for further exploration of the underlying dynamics of laser-and-nanoparticle interactions.

Electrically driven single microribbon based near-infrared exciton-polariton light-emitting diode

CrystEngComm ◽  
2021 ◽  
Author(s):  
Mingming Jiang ◽  
Fupeng Zhang ◽  
Kai Tang ◽  
Peng Wan ◽  
Caixia Kan
Keyword(s):  
High Performance ◽  
Near Infrared ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Light Sources ◽  
Coherent Light ◽  
Light Emitting ◽  
Exciton Polaritons ◽  
Laser Devices

Achieving electrically-driven exciton-polaritons has drawn substantial attention toward developing ultralow-threshold coherent light sources, containing polariton laser devices and high-performance light-emitting diodes (LEDs). In this work, we demonstrate an electrically driven...

scholarly journals Assessing the Stability of Surface Lights for use in Retrievals of Nocturnal Atmospheric Parameters

2019 ◽  
Author(s):  
Jeremy E. Solbrig ◽  
Steven D. Miller ◽  
Jianglong Zhang ◽  
Lewis Grasso ◽  
Anton Kliewer
Keyword(s):  
Near Infrared ◽  
Correlation Coefficients ◽  
Visible Spectrum ◽  
Light Sources ◽  
Infrared Observations ◽  
Spatially Resolved ◽  
Relative Standard ◽  
Geometric Variables ◽  
The Stability

Abstract. Detection and characterization of aerosols is inherently limited at night due to a lack of sensitivity—information typically provided by visible spectrum observations. The VIIRS Day/Night Band (DNB) onboard the Suomi-NPP satellite is a first-of-its-kind calibrated sensor capable of collecting visible/near-infrared observations during both day and night. Multiple studies have suggested that anthropogenic light emissions such as those from cities and gas flares may be useable as light sources for retrieval of atmospheric properties including cloud and aerosol optical depth. However, their use in this capacity requires proper characterization of their intrinsic variation, which represents a source of retrieval uncertainty. In this study we use 18 months of cloud-cleared VIIRS data collected over five selected geographic domains to assess the stability of anthropogenic light emissions and their response to varied satellite and lunar geometries. Timeseries are developed for each location in each domain for DNB radiance, four infrared channels, and satellite and lunar geometric variables, and spatially-resolved correlation coefficients are computed between DNB radiance and each of the other variables. This analysis finds that while many emissive light sources are too unstable to be used reliably for atmospheric retrievals, some sources exhibit a sufficient stability (relative standard deviation

scholarly journals Ultrafast electro-optic light with subcycle control

Science ◽  
2018 ◽  
Vol 361 (6409) ◽  
pp. 1358-1363 ◽  
Author(s):  
David R. Carlson ◽  
Daniel D. Hickstein ◽  
Wei Zhang ◽  
Andrew J. Metcalf ◽  
Franklyn Quinlan ◽  
...  
Keyword(s):  
High Speed ◽  
Near Infrared ◽  
Continuous Wave ◽  
Mode Locking ◽  
Light Sources ◽  
Electro Optic ◽  
High Pulse ◽  
Optical Cycle ◽  
Rapid Transients ◽  
And Control

Light sources that are ultrafast and ultrastable enable applications like timing with subfemtosecond precision and control of quantum and classical systems. Mode-locked lasers have often given access to this regime, by using their high pulse energies. We demonstrate an adaptable method for ultrastable control of low-energy femtosecond pulses based on common electro-optic modulation of a continuous-wave laser light source. We show that we can obtain 100-picojoule pulse trains at rates up to 30 gigahertz and demonstrate sub–optical cycle timing precision and useful output spectra spanning the near infrared. Our source enters the few-cycle ultrafast regime without mode locking, and its high speed provides access to nonlinear measurements and rapid transients.

scholarly journals Near Infrared Photoimmunotherapy with Combined Exposure of External and Interstitial Light Sources

2018 ◽  
Vol 15 (9) ◽  
pp. 3634-3641 ◽  
Author(s):  
Yasuhiro Maruoka ◽  
Tadanobu Nagaya ◽  
Kazuhide Sato ◽  
Fusa Ogata ◽  
Shuhei Okuyama ◽  
...  
Keyword(s):  
Near Infrared ◽  
Light Sources ◽  
Combined Exposure

Chaos of interband cascade lasers in the mid-infrared regime

2020 ◽  
Author(s):  
Yu Deng ◽  
Zhuo-Fei Fan ◽  
Shiyuan Zhao ◽  
Frédéric Grillot ◽  
Cheng Wang
Keyword(s):  
Semiconductor Lasers ◽  
Near Infrared ◽  
Optical Feedback ◽  
Nonlinear Dynamical Systems ◽  
Initial Conditions ◽  
Electrical Power ◽  
High Sensitivity ◽  
Light Sources ◽  
Mid Infrared ◽  
Operation Conditions

Abstract Chaos in nonlinear dynamical systems is featured with irregular appearance and with high sensitivity to initial conditions. Near-infrared semiconductor lasers subject to optical feedback from an external reflector are popular chaotic light sources, which have enabled multiple applications. Here, we report the fully-developed chaos in a mid-infrared interband cascade laser with external optical feedback. The chaos leads to significant electrical power enhancement over a frequency span of 500 MHz. In addition, the laser also exhibits periodic oscillations or low-frequency fluctuations before producing chaos, depending on the operation conditions. This work paves the way for extending chaos investigations from the near-infrared regime to the mid-infrared regime, which can stimulate potential applications in this spectral range.

scholarly journals Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

2020 ◽  
Vol 16 ◽  
pp. 415-444 ◽  
Author(s):  
Bernd Strehmel ◽  
Christian Schmitz ◽  
Ceren Kütahya ◽  
Yulian Pang ◽  
Anke Drewitz ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
High Power ◽  
Near Infrared ◽  
New Technologies ◽  
Light Sources ◽  
Hydrophobic Properties ◽  
On Demand ◽  
Nir Light ◽  
Photothermal Treatment ◽  
End Groups

Cyanines derived from heptamethines were mainly discussed regarding their functionalization to broaden the solubility in different surroundings exhibiting either hydrophilic or hydrophobic properties and to tailor made the ΔG et photopysical properties with respect to absorption and fluorescence. Electrochemical properties were additionally considered for some selected examples. The cyanines chosen comprised as end groups either indolenine, benzo[e]- or benzo[cd]indolium pattern, which facilitated to shift the absorption between 750–1000 nm. This enabled their use in applications with light sources emitting in the near-infrared (NIR) region selected from high power LEDs or lasers with line-shaped focus. The absorbers considered were discussed regarding their function as sensitizer for applications related to Chemistry 4.0 standards. These were mainly photopolymer coatings, which can be found for applications in the graphic industry or to protect selected substrates. The huge release of heat on demand upon turning ON or OFF the NIR light source enables them for photothermal treatment in processes requesting heat to initiate either chemical (activated reactions) or physical (melting, evaporation) events.

scholarly journals Eliminating the Effect of Reflectance Properties on Reconstruction in Stripe Structured Light System

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6564
Author(s):  
Zhao Song ◽  
Zhan Song ◽  
Yuping Ye
Keyword(s):  
Hybrid System ◽  
Surface Texture ◽  
Structured Light ◽  
Photometric Stereo ◽  
Free Form ◽  
Light Sources ◽  
Reconstruction Accuracy ◽  
Surface Geometry ◽  
Complex Objects ◽  
Structured Light System

The acquisition of the geometry of general scenes is related to the interplay of surface geometry, material properties and illumination characteristics. Surface texture and non-Lambertian reflectance properties degrade the reconstruction results by structured light technique. Existing structured light techniques focus on different coding strategy and light sources to improve reconstruction accuracy. The hybrid system consisting of a structured light technique and photometric stereo combines the depth value with normal information to refine the reconstruction results. In this paper, we propose a novel hybrid system consisting of stripe-based structured light and photometric stereo. The effect of surface texture and non-Lambertian reflection on stripe detection is first concluded. Contrary to existing fusion strategy, we propose an improved method for stripe detection to reduce the above factor’s effects on accuracy. The reconstruction problem for general scene comes down to using reflectance properties to improve the accuracy of stripe detection. Several objects, including checkerboard, metal-flat plane and free-form objects with complex reflectance properties, were reconstructed to validate our proposed method, which illustrates the effectiveness on improving the reconstruction accuracy of complex objects. The three-step phase-shifting algorithm was implemented and the reconstruction results were given and also compared with ours. In addition, our proposed framework provides a new feasible scheme for solving the ongoing problem of the reconstruction of complex objects with variant reflectance. The problem can be solved by subtracting the non-Lambertian components from the original grey values of stripe to improve the accuracy of stripe detection. In the future, based on stripe structured light technique, more general reflection models can be used to model different types of reflection properties of complex objects.

Light-emitting diodes as light sources for spectroscopy: Sensitivity to temperature

2017 ◽  
Vol 25 (6) ◽  
pp. 416-422 ◽  
Author(s):  
Clinton J Hayes ◽  
Kerry B Walsh ◽  
Colin V Greensill
Keyword(s):  
Ambient Temperature ◽  
Near Infrared ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Junction Temperature ◽  
Effect Of Temperature ◽  
Light Sources ◽  
Spectral Variation ◽  
Light Emitting ◽  
Full Intensity

Understanding of light-emitting diode lamp behaviour is essential to support the use of these devices as illumination sources in near infrared spectroscopy. Spectral variation in light-emitting diode peak output (680, 700, 720, 735, 760, 780, 850, 880 and 940 nm) was assessed over time from power up and with variation in environmental temperature. Initial light-emitting diode power up to full intensity occurred within a measurement cycle (12 ms), then intensity decreased exponentially over approximately 6 min, a result ascribed to an increase in junction temperature as current is passed through the light-emitting diode. Some light-emitting diodes displayed start-up output characteristics on their first use, indicating the need for a short light-emitting diode ‘burn in’ period, which was less than 24 h in all cases. Increasing the ambient temperature produced a logarithmic decrease in overall intensity of the light-emitting diodes and a linear shift to longer wavelength of the peak emission. This behaviour is consistent with the observed decrease in the IAD Index (absorbance difference between 670 nm and 720 nm, A670–A720) with increased ambient temperature, as measured by an instrument utilising light-emitting diode illumination (DA Meter). Instruments using light-emitting diodes should be designed to avoid or accommodate the effect of temperature. If accommodating temperature, as light-emitting diode manufacturer specifications are broad, characterisation is recommended.

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