Dynamic tunable LWIR achromatic metalens comprising all-As_(2)Se_(3) microstructures

In the field of long-wave infrared(LWIR) thermal imaging, vital for applications such as military surveillance and medical diagnostics, metalenses show immense potential for compact, lightweight, and low-power optical systems. However, to date, the development of LWIR broadband achromatic metalenses with dynamic tunable focus, which are suitable for both coaxial and off-axis applications, remains a large unexplored area. Herein, we have developed an extensive database of broadband achromatic all-As2Se3microstructure units for the LWIR range. Utilizing this database with the particle swarm optimization (PSO) algorithm, we have designed and demonstrated LWIR broadband achromatic metalenses capable of coaxial and off-axis focusing with three dynamic tunable states. This research may have potential applications for the design of compact, high-performance optical devices, including those with extreme depth-of-field and wide-angle imaging capabilities.

Dynamic Single/Dual-channel Filter with Tunable Fiber Bragg Gratings

The shift mechanism of Bragg wavelength with stress variation for a fiber grating is investigated in detail. The influence of strain change on reflection and bandpass is theoretically analyzed. By applying stress, the dynamic single/dual channel filter with tunable fiber Bragg gratings is achieved.

Extraordinary tunable dynamic range of electrochemical aptasensor for accurate detection of ochratoxin A in food samples

We report the design of a sensitive,electrochemical aptasensor for detection of ochratoxin A(OTA)with an extraordinary tunable dynamic sensing range.This electrochemical aptasensor is constructed based on the target induced aptamer-folding detection mechanism and the recognition between OTA and its aptamers results in the conformational change of the aptamer probe and thus signal changes for measurement.The dynamic sensing range of the electrochemical aptasensor is successfully tuned by introduction of free assistant aptamer probes in the sensing system.Our electrochemical aptasensor shows an extraordinary dynamic sensing range of 11-order magnitude of OTA concentration from 10^−8 to 10^2 ng/g.Of great significance,the signal response in all OTA concentration ranges is at the same current scale,demonstrating that our sensing protocol in this research could be applied for accurate detections of OTA in a broad range without using any complicated treatment of signal amplification.Finally,OTA spiked red wine and maize samples in different dynamic sensing ranges are determined with the electrochemical aptasensor under optimized sensing conditions.This tuning strategy of dynamic sensing range may offer a promising platform for electrochemical aptasensor optimizations in practical applications.

Optically pumped wavelength-tunable lasing from a GaN beam cavity with an integrated Joule heater pivoted on Si

Dynamically tunable laser sources are highly promising for realizing visionary concepts of integrated photonic circuits and other applications. In this paper, a Ga N-based laser with an integrated PN junction heater on Si is fabricated.The photoluminescence properties of the Ga N beam cavity are controlled by temperature, and the Joule heater provides electrically driven regulation of temperature. These two features of the cavity make it possible to realize convenient tuning of the lasing properties. The multi-functional Ga N beam cavity achieves optically pumped lasing with a single mode near 362.4 nm with a high Q-factor of 1394. The temperature of this device increases by 0–5℃ under the Joule heating effect. Then, electrical control of the lasing mode is demonstrated. The lasing resonant peak shows a continuous redshift of about 0.5 nm and the device also exhibits dynamic switching of its lasing mode. The lasing modulation can be ascribed to temperature-induced reduction of the bandgap. Our work may be of benefit for external optical modulation in future chip-based optoelectronic devices.

Classic analogue of Autler–Townes-splitting transparency using a single magneto-optical ring resonator

We show that an optical transparency can be obtained by using only one single magneto-optical ring resonator. This effect is based on the splitting of counterclockwise and clockwise modes in the ring resonator. Within a proposed resonator-waveguide configuration the superposition between the two degeneracy broken modes produces a transparency window,which can be closed, open, and modified by tuning the applied magnetic field. This phenomenon is an analogue of Autler–Townes splitting, and the magnetic field is equivalent to the strong external pump field. We provide a theoretic analysis on the induced transparency, and numerically demonstrate the effect using full-wave simulation. Feasible implication of this effect and its potential applications are also discussed.

Active tuning of Si metasurface with large area

All-dielectric metasurfaces are usually limited because of their static functionality and small scale.In this paper,we use an easy nanofabrication technique to fabricate all-dielectric metasurfaces with the advantages of having dynamic tunability and a large area.Using an anodized aluminum oxide(AAO)template as an evaporation mask,a large-area metasurface embedded in polydimethylsiloxane(PDMS)(>2 cm^(2))is fabricated.The metasurface exhibits remarkable electric dipole(ED)and magnetic dipole(MD)resonances.Based on the solvent-swelling effect of PDMS in 20%toluene,the ED/MD resonance peak shifts dynamically∼40 nm to red.So far,to the best of our knowledge,a large-area metasurface embedded in PDMS and achieved by using the AAO template method has not appeared.

Design of a widely adjustable electrochromic device based on the reversible metal electrodeposition of Ag nanocylinders

Structural colors resulting from nanostructured metallic surfaces hold a series of advantages compared to conventional chemical pigments and dyes,such as enhanced durability,tunability,scalability,and low consumption,making them particularly promising for preparing color-tunable devices.However,once these structures are fabricated,they are almost all passive devices with static nanostructures and fixed optical properties,limiting their potential applications.Here,by using a specially designed array of ordered SiO2 nanoholes as a deposition template in conjunction with the traditional reversible metal electrodeposition device(RMED),we propose a tunable reflective surface where the color of the surface can be changed as a function of the thickness of the deposited Ag nanoparticles(AgNPs).Simplified manufacturability and a large range of color tunability are achieved over previous reports by utilizing the SiO2 nanohole template,which allows the direct deposition of AgNPs while forming an array structure of Ag nanocylinders.Besides,a further thematic analysis of the physical mechanism in the proposed structure is conducted.The results show that the structural colors induced by the longitudinal localized surface plasmon resonance(LSPR)mode can be dynamically tuned from brown to purple via increasing the deposition thickness.Additionally,in combination with SiO2 nanohole templates of varying parameters,a full gamut of colors spanning the entire visible spectrum is achieved,revealing the feasibility of utilizing the properties of the LSPR mode for satisfying various color requirements.We believe that this LSPRbased multicolor RMED design will contribute to the development of full color information displays and light-modulating devices.

A spectrum-adjusted white organic light-emitting diode for the optimization of luminous efficiency and color rendering index

High luminous efficiency and high color rendering index(CRI) are both the foremost factors for white organic lightemitting diodes(WOLEDs) to serve as next generation solid-state lighting sources. In this paper, we show that both luminous efficiency and CRI can be improved by adjusting the green/red spectra of WOLEDs. With green emission spectra matching with the human photopic curve, the WOLEDs exhibit higher luminous efficiency and higher CRI. Theoretical calculation shows that by tuning the white emission spectra to maximally match with the human photopic curve, the luminous efficiency can be improved by 41.8% without altering the color coordinates, the color correlated temperature(CCT) and the external quantum efficiency(EQE) of the WOLEDs.