Hybrid Microcavity Research Articles

Ultrastable and Low-Threshold Two-Photon-Pumped Amplified Spontaneous Emission from CsPbBr3/Ag Hybrid Microcavity.

Halide perovskite materials have garnered significant research attention due to their remarkable performance in both photoharvesting photovoltaics and photoemission applications. Recently, self-assembled CsPbBr3 superstructures (SSs) have been demonstrated to be promising lasing materials. In this study, we report the ultrastable two-photon-pumped amplified stimulated emission from a CsPbBr3 SS/Ag hybrid microcavity with a low threshold of 0.8 mJ/cm2 at room temperature. The experimental results combined with numerical simulations show that the CsPbBr3 SS exhibits a significant enhancement in the electromagnetic properties in the hybrid microcavity on Ag film, leading to the uniform spatial temperature distribution under the irradiation of a pulsed laser, which is conducive to facilitate the recrystallization process of the QDs and improve their structural integrity and optical properties. This study provides a new idea for the application of CsPbBr3/Ag hybrid microcavity in photonic devices, demonstrating its potential in efficient optical amplification and upconversion lasers.

Regulating thermal management by a CsPbClBr2/Ag hybrid microcavity for stable room temperature blue lasing with low threshold

Realization of long-term stable lasing from all-inorganic perovskite supercrystals is highly desirable for practical applications in optoelectronic devices. However, lasing from perovskite supercrystals excited by continuous wave laser light remains a challenge due to the photoluminescence degradation induced by thermal accumulation. Here, we report highly stable lasing with low threshold fom a CsPbClBr2 supercrystal placed on a thin Ag film, which form a CsPbClBr2/Ag microcavity, by managing the thermal distribution inside the CsPbClBr2 supercrystal. Combined numerical simulations and lifetime measurements, the localized electric field in such a hybrid microcavity leads to a spatially localized temperature distribution, which plays a crucial role in suppressing the thermal accumulation on the surface and in eliminating non-radiative recombination defects. The effective thermal management in the hybrid microcavity renders highly stable lasing with low threshold under the irradiation of continuouw wave laser light. Our findings provide a feasible and universal approach to the development of long-term stable perovskite laser.

A WGM-FP hybrid microcavity for simultaneous measurement of NaCl concentration and temperature

Whispering gallery mode (WGM) resonator is sensitive to the external medium change due to its strong light-matter interaction. However, the temperature sensitivity of silica-based WGM resonators would cause crosstalk, which is a fatal shortcoming for those high-quality (Q) resonators. In this paper, a hybrid microcavity including WGM resonance and Fabry–Pérot (FP) interference is proposed for simultaneous measurement of NaCl concentration and temperature, using the same microcavity in the same system to obtain two types of optical signals. The experimental results indicate that the maximum measurement error of NaCl concentration and temperature without compensation is about ± 0.026 % and ± 1.1 °C, while they would be ± 0.012 % and ± 0.3 °C after compensation. Sharing one microcavity enables temperature compensation to achieve temperature synchronization, and sharing of one system ensures the simplicity and stability of the sensing platform.

Hybrid Microcavity Lasers: Principle, Design, and Practical Application

AbstractControl coupling and synchronization of lasers has become increasingly attractive for their applications in spectroscopy, imaging, sensing, secret communication, and optical networks. As complex microcavities emerge, more complicated light–matter interactions, along with the resulting distinct lasing emission behavior, is induced in these hybrid microcavities. This review summarizes the most important advances and current deep insights into the inherent relationship between the hybrid microcavity geometries and lasing behaviors, which are classified as the modulated lasing output freedom, including wavelength, angular momentum, mode, direction, and their multiple combinations. Finally, based on scientific research and practical application, the challenges and prospects of future development of hybrid microcavities are proposed, hoping to provide valuable inspiration for further optimizing hybrid microcavities to achieve low thresholds, small divergence angles, and single‐mode microcavity lasers.

Tunable, Single-Wavelength Fiber Laser Based on Hybrid Microcavity Functionalized by Atomic Layer Deposition

A tunable fiber laser based on a high-quality-factor (high- <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> ) hybrid microcavity (HM) is proposed and demonstrated. As far as we know, this is the first report of fabricating the HM by coating TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> film with varied thickness on the SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> microsphere surface by atomic layer deposition technique, with the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> -factor maintained to be above 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> . Ultra-narrow bandwidth whispering gallery mode spectrum of the HM is used for mode-selection in a double-ring fiber cavity, achieving tunable single-wavelength fiber laser output with 3dB bandwidth of about 16.20 pm, signal-to-noise ratio of ∼40 dB and wavelength tuning range of ∼220 pm. The proposed novel tunable, single-wavelength fiber laser with wide tuning range and high compactness can be potentially used for optical communication and sensing applications. © 2022 Optica Publishing Group.

Thermal oscillation in the hybrid Si3N4 - TiO2 microring.

The hybrid microcavity composed of different materials shows unique thermal-optical properties such as resonance frequency shift and small thermal noise fluctuations with the temperature variation. Here, we have fabricated the hybrid Si3N4 - TiO2 microring, which decreases the effective thermo-optical coefficients (TOC) from 23.2pm/K to 11.05pm/K due to the opposite TOC of these two materials. In this hybrid microring, we experimentally study the thermal dynamic with different input powers and scanning speeds. The distorted transmission and thermal oscillation are observed, which results from the non-uniform scanning speed and the different thermal relaxation times of the Si3N4 and the TiO2. We calibrate the distorted transmission spectrum for the resonance measurement at the reverse scanning direction and explain the thermal oscillation with a thermal-optical coupled model. Finally, we analyse the thermal oscillation condition and give the diagram about the oscillation region, which has significant guidance for the occurrence and avoidance of the thermal oscillation in practical applications.

Photonic-Plasmonic Hybrid Microcavity with Ultra-High Quality Factor Regulated by Bowtie Plasmonic Nanoantenna

Photonic-Plasmonic Hybrid Microcavity with Ultra-High Quality Factor Regulated by Bowtie Plasmonic Nanoantenna

Tale of Two Resonances: Waveguide–Plasmon Coupling and High Q-Factor Engineering on the Nanoscale

Localized surface plasmon (LSP) excitations provide an efficient strategy for advancing nanophotonic designs and applications where strong field enhancement and confinement are often required on the nanoscale. They represent an important plasmonic paradigm for achieving strong light–matter interactions in both linear and nonlinear regimes, enabling the development of high-performance chemical and biological sensing approaches and nonlinear optics with low light intensities. However, the LSP resonance line width, limited by both radiative and resistive losses of metallic nanostructures, is significantly larger than the line width of the waveguided modes supported by low-loss dielectric microcavities with a significantly lower field confinement. Hybrid microcavity–plasmonic systems are, therefore, often used to reduce the resonant line width which improves the detection spectral resolution while maintaining strong confinement. Employing the remarkable quality factors of whispering gallery mode (WGM) microresonators, the hybrid LSP-WGM systems demonstrate sensing capabilities down to the single-molecule level. In this Perspective, we review the recent advances in the hybridization of LSPs and WGMs, focusing on the fundamental understanding of the underlying coupling mechanisms and corresponding mode hybridization regimes. We further discuss opportunities for applying heterogeneous plasmonic–photonic integration to tailor the nanoscale light–matter interactions and realize novel waveguide–plasmon coupling based nontrivial responses and highlight their prospective applications in quantum optics, chiral spin-optics, nonlinear nanophotonics, and sensing.

Electrically tunable WGM lasing in a metal-dielectric core–shell hybrid microcavity

We present a hybrid cavity designed to manipulate lasing modes, consisting of a metal-dielectric core–shell hybrid microcavity fabricated using a simple brush-coating method. Single and multiple modes can be obtained in the proposed laser device by the trade-off between loss and gain. Moreover, we achieve electrically tunable whispering-gallery-mode lasing by employing the thermo-optic effect in the hybrid microcavity. The lasing peak of the modes can be electrically tuned by quantitative control of Joule heating. We measure a tuning rate of 15.3 pm/J for all the lasing peaks.

Design of electrically driven single-photon source based on intra-cavity contacted microcavity with oxide-confined optical apertures emitting at 1.3 μm

We propose a hybrid microcavity design of a 1.3 μm range electrically driven single-photon source (SPS) consisting of two high-contrast dielectric distributed Bragg reflectors which surround a 3λ-thick semiconductor cavity with two intra-cavity contact layers and four 40-nm-thick oxide-confined apertures. According to 3D finite-difference time-domain modelling, the overall photon-extraction efficiency of ~74% and the Purcell factor of ~13 can be obtained by properly adjusting the position of oxide-confined apertures relative to the electric field of the fundamental optical mode. The studied SPS design also demonstrates a coupling efficiency of up to 13% within numerical aperture 0.12 in contrast to ~5% reached for a conventional semiconductor micropillar.

Pump-controlled RGB single-mode polymer lasers based on a hybrid 2D–3D μ-cavity for temperature sensing

Abstract Single mode lasers, particularly red-green-blue (RGB) colors, have attracted wide attention due to their potential applications in the photonic field. Here, we realize the RGB single mode lasing in a hybrid two-dimension and three-dimension (2D–3D) hybrid microcavity (μ-cavity) with a low threshold. The hybrid 2D–3D μ-cavity consists of a polymer fiber and a microsphere. Typical RGB polymer film consisting gain materials are cladded on a fiber. To achieve single mode lasing, the polymer fiber therein serves as an excellent gain cavity to provide multiple lasing modes while the microsphere acts as a loss channel to suppress most of the lasing modes. Mode switching can be realized by adjusting the pump position. It can be attributed to the change of coupled efficiency between gain μ-cavity and loss μ-cavity. Our work will provide a platform for the rational design of nanophotonic devices and on-chip communication.

Selection of Emission Wavelength of Lasing via a Hybrid Microcavity

In the applications of optical communication and light-matter interaction manipulation, the capability of on-demand lasing output with programmable and continuous wavelength tunability over a broad spectral range under low threshold is key functionality. However, the ability to control multiwavelength lasing characteristics within a small mode volume with high reconfigurability remains challenging. The number of dyes and the emission wavelengths of existing materials always restrict the color gamut. In this Letter, we introduce a selection of emission wavelength laser by injecting Rhodamine 6G solution mixed with $\mathrm{Au}$ nanoparticles in the metal-cladded slab-capillary hybrid microcavity. A mechanism for tuning laser emission wavelengths is designed by manipulating the diameter of $\mathrm{Au}$ nanoparticles in Rhodamine 6G solution. Precision control of distinctive lasing wavelengths and a narrower peak are achieved, along with a stable lasing beam output from both ends of the capillary due to coherent superposition. Our findings offer possibilities for realizing a micro selection of emission wavelength laser from a single overall structure.

Pool Boiling Performance of Water and Self-Rewetting Fluids on Hybrid Functionalized Aluminum Surfaces

The boiling performance of functionalized hybrid aluminum surfaces was experimentally investigated for water and self-rewetting mixtures of water and 1-butanol. Firstly, microstructured surfaces were produced via chemical etching in hydrochloric acid and the effect of the etching time on the surface morphology was evaluated. An etching time of 5 min was found to result in pitting corrosion and produced weakly hydrophilic microstructured surfaces with many microcavities. Observed cavity-mouth diameters between 3.6 and 32 μm are optimal for efficient nucleation and provided a superior boiling performance. Longer etching times of 10 and 15 min resulted in uniform corrosion and produced superhydrophilic surfaces with a micropeak structure, which lacked microcavities for efficient nucleation. In the second stage, hybrid surfaces combining lower surface energy and a modified surface microstructure were created by hydrophobization of etched aluminum surfaces using a silane agent. Hydrophobized surfaces were found to improve boiling heat transfer and their boiling curves exhibited a significantly lower superheat. Significant heat transfer enhancement was observed for hybrid microcavity surfaces with a low surface energy. These surfaces provided an early transition into nucleate boiling and promoted bubble nucleation. For a hydrophobized microcavity surface, heat transfer coefficients of up to 305 kW m−2 K−1 were recorded and an enhancement of 488% relative to the untreated reference surface was observed. The boiling of self-rewetting fluids on functionalized surfaces was also investigated, but a synergistic effect of developed surfaces and a self-rewetting working fluid was not observed. An improved critical heat flux was only obtained for the untreated surface, while a lower critical heat flux and lower heat transfer coefficients were measured on functionalized surfaces, whose properties were already tailored to promote nucleate boiling.

Opto-fluidic-plasmonic liquid-metal core microcavity

A hybrid microcavity based on the liquid-metal-filled silica microbubble is experimentally demonstrated, which supports both plasmonic and optical whispering gallery modes. The high quality (Q)-factor plasmonic mode of liquid metal is demonstrated via controlling the polarization of the probe laser as well as changing the liquids in the microbubble. Additionally, we reveal an unconventional Q-factor enhancement effect in the bottle microresonator. The liquid metal (mercury) could dissolve various metals and solids, meriting the optofluidic type of sensing. Combining the two kinds of high-Q resonances in the hybrid microcavity, we could probe the optical, mechanical, and thermal properties of solvents in liquid metal, providing a unique experimental platform for realizing multi-parameter optical sensing and making the detection and identification of metal and alloy possible.

Research advances of ultrahigh-&amp;lt;italic&amp;gt;Q&amp;lt;/italic&amp;gt; on-chip microcavity photonics

Optical microcavities can trap light within both spatial and temporal dimensions, giving rise to an enhancement of light-matter interaction, which are employed extensively for fundamental studies of optical physics and photonic applications. In particular, because of its ultrahigh- Q factors and small mode volumes, optical whispering-gallery-mode (WGM) microcavities, confining light by total internal reflection, act as the frontier of the state-of-art microcavity studies. As the recent significant development of the micro-/nano-fabrication technology for semiconductor chips and optical materials, on-chip integration becomes one of the most important trends for WGM microcavities. For example, on-chip optical microcavities have been playing a pivotal role in diverse fields, including photonic chip, broadband integrated optical computing, on-chip optical interconnects, microcomb-based precise measurement, etc. In this review, we introduce the research advances of microlasers, nonlinear optics, photonic integrated circuits, and ultrasensitive optical sensing in ultrahigh- Q on-chip microcavities. The specific progresses are organized as follows: (1) Ultralow-threshold lasing in on-chip WGM microcavity can be achieved by either introducing active materials to the resonator or using intrinsic nonlinearities of the resonator material. Moreover, diverse functional microlasers are also realized, such as unidirectional emission, chaotic laser, symmetry-broken laser, orbit angular momentum laser, parity-time reversal symmetry laser, etc. (2) Numerous optical nonlinear effects with high efficiency have been experimentally generated in WGM microcavities, including second harmonic generation, four-wave mixing, stimulated Brillouin scattering, stimulated Raman scattering. Furthermore, high-performance and multifunctional photonic applications have been developed based on microcavity-engineered nonlinear optics. In particular, optical frequency combs based on Kerr nonlinear effects in WGM microcavities, are applied extensively for integrated precision measurement applications like ultrafast LiDAR, optical clocks, and astronomical spectrum calibration. (3) As one of the most important elements in photonic integrated circuit, the optical microcavity has been widely used in the realization of photonic functional devices, such as signal sources, storage, filter, isolator, and modulator. Moreover, it also has been applied to broadband coupling between individual photonic devices. (4) WGM microcavity sensing attracts much attention due to ultra-high sensitivity and label-free nature. The last decade has witnessed the tremendous progress of on-chip microcavity sensing, and the sensing ability has been widely exploited for detecting single nanoparticles, biological molecules, magnetic fields, angular velocity, temperature, etc. Finally, we provide an outlook on the future developments of on-chip ultrahigh- Q microcavity photonics. While numerous progresses have been achieved in ultrahigh- Q on-chip microcavities, a few challenges and obstacles still exist in practical applications. For example, the optical soliton microcombs suffer from the low conversion efficiency and limited wavelength bandwidth; the bandwidth of the optical isolator by the optical microcavities is narrow; the electro-optic modulator based on microcavities cannot combine the broad modulation bandwidth and low power consumption; it is highly challenging for the specific identification in microcavity biosensing. In order to further push forward the development of on-chip microcavity photonics, new principles, new mechanisms, and new materials are required to be explored. The considerable solution may focus on the non-trivial interaction in complex systems, such as hybrid microcavity structures, regulation of optical field by multiple nonlinear optical effects, optical wave chaos in asymmetric microcavities, non-Hermitian physics, and topological photonics.

Coupled-mode induced transparency via Ohmic heating in a single polydimethylsiloxane-coated microbubble resonator.

We demonstrate an approach for the realization of coupled-mode induced transparency (CMIT) in a hybrid polydimethylsiloxane (PDMS)-coated silica microbubble resonator, with an Au microwire inserted in the hollow channel. Owing to the large negative thermo-optics coefficient of PDMS, different radial order modes with opposite thermal sensitivities can coexist in this hybrid microcavity. By applying a current through the Au microwire, which acts as a microheater, the generated Ohmic heating could thermally tune the resonance frequencies and the frequency detuning of the coupled mode to achieve controllable CMIT. This platform offers an efficient and convenient way to obtain controllable CMIT for applications, such as label-free biosensing and quantum information processing.

Dual-band lasing from ZnO/CsPbBr3 core/shell microcavity

It is a challenge to design and fabricate micro/nano-scaled dual-band even multi-band lasers for potential nanophotonic application. Here, a ZnO/CsPbBr3 core/shell microrod was fabricated as a hybrid microcavity for dual-band lasing. The stimulated ultraviolet and visible emission was realized simultaneously under the optical pumping. The lasing properties and the resonance mechanism of the dual-band laser was investigated experimentally and confirmed by 2D finite difference time domain simulation.

Mode and sensing properties of a silicon-based hybrid plasmonic microring resonator

A silicon-based hybrid plasmonic microring resonator consisting of a silicon-on-insulator ring which is separated from a silver nanoring by a low-permittivity dielectric is proposed for sensing applications. Benefitting from the hybrid modes and the circular-shaped cross section of nanoring, the hybrid microcavity can attract part of the cavity energy from the silicon ring microcavity, achieving high energy ratio and high refractive index sensitivity. The performance of the hybrid microcavity has been investigated by employing a finite element method and analyzed considering the different structure geometry, showing high quality factor of 1181, small mode volume of 0.154 µm3 and large refractive index sensitivity of 529.6 nm/RIU (refractive index unit). Thus, the presented silicon-based hybrid plasmonic microring resonator provides the potential applications in sensing at deep sub-wavelength scale.

White Beam Lasing from a Hybrid Microcavity with Slab-Capillary Mode Coupling

Creating a multicolor laser on a single microchip has become a subject of great interest, with white-light lasers as the ultimate goal. This requires a high-quality-factor, multichannel cavity structure supporting the lasing of all elementary colors simultaneously, with strongly enhanced ultralow-threshold emission. The authors present a hybrid microcavity that eliminates background noise and integrates multiple capillaries on a slab, achieving multiwavelength lasing. This broadly tunable multichannel laser should find use in $e.g.$ optical interconnects and multiplexing, multiagent chemical and biological detection, solid-state lighting, solar cells, and superbright microdisplays.

(Invited) Electrochemical Preparation of Micro and Nano Structures and Systems in Silicon for (Bio)Sensing and Nano(Medicine) Applications

When dealing with biosensing and nanomedicine applications the length scale of targets may vary over more than 5 orders of magnitude moving from the molecular level (0.1-1 nm) up to the cell level (1-10 μm). A number of micro and nanostructuring technologies have been developed over the years to enable the preparation of both structures and systems with length scales suitable to match specific biological targets. In this talk, electrochemical preparation of nano and micro structures and systems in silicon with length scales spanning over 5 order of magnitudes, able to target different applications both in (nano)medicine (e.g. sinusoid-like liver on a chip, nanopillars for cell transfection, 3D microincubators for tumor cell screening) and (bio)sensing (e.g. microneedles for transdermal biosensing, optical biosensors for point-of-care clinical diagnostics, chemitransitor sensors for environmental monitoring), is presented and discussed. 1. S.Mariani, V. Robbiano, L. M. Strambini, A. Debrassi, G. Egri, L. Dähne, G. Barillaro, Layer-by-layer biofunctionalization of nanostructured porous silicon for high-sensitivity and high-selectivity label-free affinity biosensing, Nature Communications, 9, 5256, 1-13 (2018) 2. B. Delalat, C. Cozzi, S. R. Ghaemi, G. Polito, F. E. Kriel, T. D. Michl, F. J. Harding, C. Priest, G. Barillaro, N. H. Voelcker, Microengineered Bioartificial Liver Chip for Drug Toxicity Screening, Advanced Functional Materials 1801825 (2018).3. Robbiano, G. M. Paterno, A. A. La Mattina, S. G. Motti, G. Lanzani, F. Scotognella, G. Barillaro, Room-Temperature Low-Threshold Lasing From Monolithically Integrated Nanostructured Porous Silicon Hybrid Microcavities, ACS Nano12, 4536−4544 (2018). 4. J. Harding, S. Surdo, B. Delalat, C. Cozzi, R. Elnathan, S. Gronthos, N. H. Voelcker, G. Barillaro, Ordered Silicon Pillar Arrays Prepared by Electrochemical Micromachining: Substrates for High-Efficiency Cell Transfection, ACS Applied Materials and Interfaces, 8 (43), 29197-29202 (2016). 5. Mariani, L. M. Strambini, G. Barillaro, Femtomole Detection Of Proteins Using A Label-Free Nanostructured Porous Silicon Interferometer For Perspective Ultra-Sensitive Biosensing, ACS Analytical Chemistry, 88 (17), 8502-8509 (2016). 6. Mariani, L. Pino, L. M. Strambini, L. Tedeschi, G. Barillaro, 10000-Fold Improvement in Protein Detection Using Nanostructured Porous Silicon Interferometric Aptasensors, ACS Sensors, 1, 1471-1479(2016). 7. M. Sainato, L.M. Strambini, S. Rella, E. Mazzotta, G. Barillaro, Sub-Parts Per Million NO2 Chemi-Transistor Sensors Based on Composite Porous Silicon/Gold Nanostructures Prepared by Metal-Assisted Etching, ACS Applied Materials and Interfaces 7, 7136 (2015). 8. M. Strambini, A. Longo, S. Scarano, T. Prescimone, I. Palchetti, M. Minunni, D. Giannessi, G. Barillaro, Self-Powered Microneedle-Based Biosensors for Pain-Free High-Accuracy Measurement of Glycaemia in Interstitial Fluid, Biosensors and Bioelectronics,66, 162 (2015).