Microcavity exciton-polaritons,formed by strong light-matter coupling,are essential for realizing Bose-Einstein condensation and low-threshold lasing.Such polaritonic lasing and condensation have been demonstrated in ...Microcavity exciton-polaritons,formed by strong light-matter coupling,are essential for realizing Bose-Einstein condensation and low-threshold lasing.Such polaritonic lasing and condensation have been demonstrated in Ⅲ-Ⅴ semiconductors at liquid helium temperatures.However,the complex fabrication of these microcavities and operating temperatures limit their room-temperature practical application.Here,we experimentally realize room-temperature exciton-polariton condensation and polaritonic lasing in a CsPbBr_(3)perovskite planar microcavity fabricated by the pressing process.Angleresolved photoluminescence spectra demonstrate the strong light-matter coupling and the formation of exciton-polaritons in such a pressed microcavity.Above the critical threshold,mass polaritons accumulating at the bottom of dispersion lead to a narrow emission linewidth and pronounced blueshift,further reinforcing the Bose-Einstein condensation and polaritonic lasing in this system.Our results offer a feasible and effective approach to investigate exciton-polariton condensation and polariton lasing at room temperature.展开更多
We numerically study the enhancement factor of energy density and absorption efficiency inside the double cylindrical microcavities based on a triple-band metamaterial absorber. The compact single unit cell consists o...We numerically study the enhancement factor of energy density and absorption efficiency inside the double cylindrical microcavities based on a triple-band metamaterial absorber. The compact single unit cell consists of concentric gold rings with a gold disk in the center and a metallic ground plane separated by a dielectric layer. We demonstrate that the multilayer structure with subwavelength electromagnetic confinement allows 104-105-fold enhancement of the electromagnetic energy density inside the double cavities and contains the most energy of the incoming light. Particularly, the enhancement factor of energy density G shows strong ability of localizing light and some regularity as the change of the thickness of the dielectric slab and dielectric constant. At the normal incidence of electromagnetic radiation, the obtained reflection spectra show that the resonance frequencies of the double microcavities operate in the range of 10-30μm. We also calculate the absorption efficiency C, which can reach 95%, 97% and 95% at corresponding frequency by optimizing the structure＇s geometry parameters. Moreover, the proposed structure will be insensitive to the polarization of the incident wave due to the symmetry of the double cylindrical microcavities. The proposed optical metamaterial is a promising candidate as absorbing elements in scientific and technical applications due to its extreme confinement, multiband absorption and polarization insensitivity.展开更多
The photoluminescence(PL) properties of porous silicon microcavities(PSMs) in the visible range at room temperature are improved by doping the rare earth ytterbium(Yb) into PSMs prepared by the electrochemical etching...The photoluminescence(PL) properties of porous silicon microcavities(PSMs) in the visible range at room temperature are improved by doping the rare earth ytterbium(Yb) into PSMs prepared by the electrochemical etching method.It is observed that PSMs doped with the rare earth have an emission band around 630 nm.Compared with the single-layer porous silicon(PS) film,the PSMs doped with Yb have narrower and stronger PL spectrum.展开更多
Photonic-plasmonic hybrid microcavities,which possess a higher figure of merit Q/V(the ratio of quality factor to mode volume)than that of pure photonic microcavities or pure plasmonic nano-antennas,play key roles in ...Photonic-plasmonic hybrid microcavities,which possess a higher figure of merit Q/V(the ratio of quality factor to mode volume)than that of pure photonic microcavities or pure plasmonic nano-antennas,play key roles in enhancing light–matter interaction.In this review,we summarize the typical photonic-plasmonic hybrid microcavities,such as photonic crystal microcavities combined with plasmonic nano-antenna,whispering gallery mode microcavities combined with plasmonic nano-antenna,and Fabry–Perot microcavities with plasmonic nano-antenna.The physics and applications of each hybrid photonic-plasmonic system are illustrated.The recent developments of topological photonic crystal microcavities and topological hybrid nano-cavities are also introduced,which demonstrates that topological microcavities can provide a robust platform for the realization of nanophotonic devices.This review can bring comprehensive physical insights of the hybrid system,and reveal that the hybrid system is a good platform for realizing strong light–matter interaction.展开更多
By using a Fourier series expansion method combined with Chew＇s perfectly matched layers （PMLs）, we analyze the frequency and quality factor of a micro-cavity on a two-dimensional photonic crystal is analyzed. Comp...By using a Fourier series expansion method combined with Chew＇s perfectly matched layers （PMLs）, we analyze the frequency and quality factor of a micro-cavity on a two-dimensional photonic crystal is analyzed. Compared with the results by the method without PML and finite-difference time-domain （FDTD） based on supercell approximation, it can be shown that by the present method with PMLs, the resonant frequency and the quality factor values can be calculated satisfyingly and the characteristics of the micro-cavity can be obtained by changing the size and permittivity of the point defect in the micro-cavity.展开更多
We numerically study the near field enhancement and absorption properties inside the double cylindrical microcavities based on triple-band metamaterial absorber. The compact single unit cell consists of concentric gol...We numerically study the near field enhancement and absorption properties inside the double cylindrical microcavities based on triple-band metamaterial absorber. The compact single unit cell consists of concentric gold rings each with a gold disk in the center, and a metallic ground plane separated by a dielectric layer. At the normal incidence of electromagnetic radiation, the obtained reflection spectra show that the resonance frequencies of the double microcavities are 16.65 THz, 20.65 THz, and 25.65THz, respectively. We also calculate the values of contrast C （C = 1 - Rmin）, which can reach 95%, 97%, and 95% at the corresponding frequencies by optimizing the geometry parameters of structure. Moreover, we demon- strate that the multilayer structure with subwavelength electromagnetic confinement allows 104 -105-fold enhancement of the electromagnetic energy density inside the double cavities, which contains the most energy of the incoming electro- magnetic radiation. Moreover, the proposed structure will be insensitive to the polarization of the incident wave due to the symmetry of the double cylindrical microcavities. The proposed optical metamaterial is a promising candidate as an absorbing element in scientific and technical applications because of its extreme confinement, multiband absorptions, and polarization insensitivity.展开更多
We fabricate a-Si/a-SiN_(z) superlattices and a one-dimensional amorphous silicon nitride photonic crystalmicrocavity by plasma enhancement chemical vapor deposition(PECVD).To improve the light-emitting efficiency of ...We fabricate a-Si/a-SiN_(z) superlattices and a one-dimensional amorphous silicon nitride photonic crystalmicrocavity by plasma enhancement chemical vapor deposition(PECVD).To improve the light-emitting efficiency of the nc-Si/a-SiN_(z)superlattices,which are made from a-Si/a-SiN_(z)superlattices by laser annealing,an nc-Si quantum dot array is inserted into the photonic crystal microcavity.Raman spectroscopy and transmission electron microscopy analysis show that nc-Si with a size of 4nm,which is close to the designed thickness of the a-Si sublayers,is formed in the a-Si sublayers.Owing to microcavity effects,the PL peak of the nc-Si/a-SiN_(z)superlattices embedded in the microcavity is strongly narrowed,and the intensity of the PL is enhanced by two orders of magnitude with respect to the emission of A/2-thick nc-Si/a-SiN_(z)superlattices.Light emission at a cavity-resonant frequency from the nc-Si/a-SiN_(z)superlattices is enhanced while other frequencies are forbidden.This leads to the narrowing of the PL spectrum and enhancement of the intensity.展开更多
We present the first findings of the new electrically- and optically-detected magnetic resonance technique [ED electron spin resonance (EDESR) and (ODMR)] which reveal single point defects in the ultra-narrow silicon ...We present the first findings of the new electrically- and optically-detected magnetic resonance technique [ED electron spin resonance (EDESR) and (ODMR)] which reveal single point defects in the ultra-narrow silicon quantum wells (Si-QW) confined by the superconductor δ-barriers. This technique allows the ESR identification without the application of the external cavity as well as a high frequency source and recorder, with measuring the only magnetoresistance (EDESR) and transmission (ODMR) spectra within frameworks of the excitonic normal-mode coupling (NMC) caused by the microcavities embedded in the Si-QW plane. The new resonant positive magnetoresistance data are interpreted here in terms of the interference transition in the diffusive transport of free holes respectively between the weak antilocalization regime in the region far from the ESR of a paramagnetic point defect located inside or near the conductive channel and the weak localization regime in the nearest region of the ESR of that defect.展开更多
High-performance optical quantum memories serving as quantum nodes are crucial for the distribution of remote entanglement and the construction of large-scale quantum networks.Notably,quantum systems based on single e...High-performance optical quantum memories serving as quantum nodes are crucial for the distribution of remote entanglement and the construction of large-scale quantum networks.Notably,quantum systems based on single emitters can achieve deterministic spin–photon entanglement,which greatly simplifies the difficulty of constructing quantum network nodes.Among them,optically interfaced spins embedded in solid-state systems,as atomic-like emitters,are important candidate systems for implementing long-lived quantum memory due to their stable physical properties and robustness to decoherence in scalable and compact hardware.To enhance the strength of light-matter interactions,optical microcavities can be exploited as an important tool to generate high-quality spin–photon entanglement for scalable quantum networks.They can enhance the photon collection probability and photon generation rate of specific optical transitions and improve the coherence and spectral purity of emitted photons.For solid-state systems,open Fabry–Pérot cavities can couple single emitters that are not in proximity to the surface,avoiding significant spectral diffusion induced by the interfaces while maintaining the wide tunability,which enables addressing of multiple single emitters in the frequency and spatial domain within a single device.This review described the characteristics of single emitters as quantum memories with a comparison to atomic ensembles,the cavity-enhancement effect for single emitters and the advantages of different cavities,especially fiber Fabry–Pérot microcavities.Finally,recent experimental progress on solid-state single emitters coupled with fiber Fabry–Pérot microcavities was also reviewed,with a focus on color centers in diamond and silicon carbide,as well as rare-earth dopants.展开更多
Whispering gallery modes (WGMs) were first discovered for sound waves in the whispering gallery of St Paul’s Cathedral and explained by Rayleigh [1] in 1878. In 1961, Garrett et al.[2] applied the concept of WGMs to ...Whispering gallery modes (WGMs) were first discovered for sound waves in the whispering gallery of St Paul’s Cathedral and explained by Rayleigh [1] in 1878. In 1961, Garrett et al.[2] applied the concept of WGMs to optical systems and realized stimulated emissions in Sm2+-doped CaF2 spheres.Since then, WGMs have been widely and intensively studied in a range of micro-sized systems, including microdroplets,microspheres, microtoroids, microdisks, and microtubes.展开更多
The coupling between optical and mechanical degrees of freedom has been of broad interest for a long time. However, it is only until recently, with the rapid development of optical mierocavity research, that we are ab...The coupling between optical and mechanical degrees of freedom has been of broad interest for a long time. However, it is only until recently, with the rapid development of optical mierocavity research, that we are able to manipulate and utilize this coupling process. When a high Q microeavity couples to a mechanical resonator, they can consolidate into an optomeehanieal system. Benefitting from the unique characteristics offered by optomeehanical coupling, this hybrid system has become a promising platform for ultrasensitive sensors to detect displacement, mass, force and acceleration. In this review, we introduce the basic physical concepts of cavity optomechanies, and describe some of the most typical experimental cavity optomechanical systems for sensing applications. Finally, we discuss the noise arising from various sources and show the potentiality of optomechanical sensing towards quantum-noise-limited detection.展开更多
In this study, we investigate the fabrication of periodically poled lithium niobate(PPLN) microdisk cavities on a chip. These resonators are fabricated from a PPLN film with a 16 μm poling period on insulator using c...In this study, we investigate the fabrication of periodically poled lithium niobate(PPLN) microdisk cavities on a chip. These resonators are fabricated from a PPLN film with a 16 μm poling period on insulator using conventional microfabrication techniques.The quality factor of the PPLN microdisk resonators with a 40-μm radius and a 700-nm thickness is 6.7×10~5. Second harmonic generation(SHG) with an efficiency of 2.2×10^(-6) mW(-1) is demonstrated in the fabricated PPLN microdisks. The nonlinear conversion efficiency could be considerably enhanced by optimizing the period and pattern of the poled structure and by improving the cavity quality factors.展开更多
It is essential to develop a single mode operation and improve the performance of lasing in order to ensure practical applicability of microlasers and nanolasers. In this paper, two hexagonal microteeth with varied na...It is essential to develop a single mode operation and improve the performance of lasing in order to ensure practical applicability of microlasers and nanolasers. In this paper, two hexagonal microteeth with varied nanoscaled air-gaps of a ZnO microcomb are used to construct coupled whispering-gallery cavities. This is done to achieve a stable single mode lasing based on Vernier effect without requiring any complicated or sophisticated manipulation to achieve positioning with nanoscale precision. Optical gain and the corresponding ultraviolet lasing performance were improved greatly through coupling with localized surface plasmons of Pt nanoparticles. The ZnO/Pt hybrid microcavities achieved a seven-fold enhancement of intensity of single mode lasing with higher side- mode suppression ratio and lower threshold. The mechanism that led to this enhancement has been described in detail.展开更多
Optical microcavities have attracted tremendous interest in both fundamental and applied research in the past few decades, thanks to their small footprint, easy integrability, and high quality factors. Using total int...Optical microcavities have attracted tremendous interest in both fundamental and applied research in the past few decades, thanks to their small footprint, easy integrability, and high quality factors. Using total internal reflection from a dielectric interface or a photonic band gap in a periodic system, these photonic structures do not rely on conventional metal-coated mirrors to confine light in small volumes, which have brought forth new developments in both classical and quantum optics. This focus issue showcases several such developments and related findings, which may pave the way for the next generation of on-chip photonic devices based on microcavities.展开更多
Quantum state transfer in optical microcavities plays an important role in quantum information processing and is essential in many optical devices such as optical frequency converters and diodes.Existing schemes are e...Quantum state transfer in optical microcavities plays an important role in quantum information processing and is essential in many optical devices such as optical frequency converters and diodes.Existing schemes are effective and realized by tuning the coupling strengths between modes.However,such approaches are severely restricted due to the small amount of strength that can be tuned and the difficulty performing the tuning in some situations,such as in an on-chip microcavity system.Here we propose a novel approach that realizes the state transfer between different modes in optical microcavities by tuning the frequency of an intermediate mode.We show that for typical functions of frequency tuning,such as linear and periodic functions,the state transfer can be realized successfully with different features.To optimize the process,we use the gradient descent technique to find an optimal tuning function for a fast and perfect state transfer.We also showed that our approach has significant nonreciprocity with appropriate tuning variables,where one can unidirectionally transfer a state from one mode to another,but the inverse direction transfer is forbidden.This work provides an effective method for controlling the multimode interactions in on-chip optical microcavities via simple operations,and it has practical applications in all-optical devices.展开更多
We fabricate photonic crystal slab microcavities embedded with GaAs quantum dots by electron beam lithography and droplet epitaxy. The Purcell effect of exciton emission of the quantum dots is confirmed by the micro p...We fabricate photonic crystal slab microcavities embedded with GaAs quantum dots by electron beam lithography and droplet epitaxy. The Purcell effect of exciton emission of the quantum dots is confirmed by the micro photoluminescence measurement. The resonance wavelengths, widths, and polarization are consistent with numerical simulation results.展开更多
By overcoming fabrication limitations, we have successfully fabricated silica toroid microcavities with both large diameter(of 1.88 mm) and ultra-high-Q factor(of 3.3 × 10~8) for the first time, to the best of ou...By overcoming fabrication limitations, we have successfully fabricated silica toroid microcavities with both large diameter(of 1.88 mm) and ultra-high-Q factor(of 3.3 × 10~8) for the first time, to the best of our knowledge. By employing these resonators, we have further demonstrated low-threshold Kerr frequency combs on a silicon chip,which allow us to obtain a repetition rate as low as 36 GHz. Such a low repetition rate frequency comb can now bedirectly measured through a commercialized optical-electronic detector.展开更多
Optical whispering gallery microcavities with high-quality factors have shown great potential toward achieveing ultrahigh-sensitivity sensing up to a single molecule or nanoparticle, which raises a huge demand on a de...Optical whispering gallery microcavities with high-quality factors have shown great potential toward achieveing ultrahigh-sensitivity sensing up to a single molecule or nanoparticle, which raises a huge demand on a deep theoretical insight into the crucial phenomena such as the mode shift, mode splitting, and mode broadening in sensing experiments. Here we propose an intuitive model to analyze these phenomena from the viewpoint of the nanoparticle-induced multiple scattering of the azimuthally propagating mode(APM). The model unveils explicit relations between these phenomena and the phase change and energy loss of the APM when scattered at the nanoparticle; the model also explains the observed polarization-dependent preservation of one resonance and the particle-dependent redshift or blueshift. The model indicates that the particle-induced coupling between the pair of unperturbed degenerate whispering gallery modes(WGMs) and the coupling between the WGMs and the free-space radiation modes, which are widely adopted in current theoretical formalisms, are realized via the reflection and scattering-induced free-space radiation of the APM, respectively, and additionally exhibits the contribution of cross coupling between the unperturbed WGMs and other different WGMs to forming the splittingresonant modes, especially for large particles.展开更多
We propose a temperature-insensitive refractive index（RI） fiber sensor based on a Mach–Zehnder interferometer. The sensor with high sensitivity and a robust structure is fabricated by splicing a short photonic crys...We propose a temperature-insensitive refractive index（RI） fiber sensor based on a Mach–Zehnder interferometer. The sensor with high sensitivity and a robust structure is fabricated by splicing a short photonic crystal fiber（PCF） between two single-mode fibers, where two microcavities are formed at both junctions because of the collapse of the PCF air holes. The microcavity with a larger equatorial dimension can excite higher-order cladding modes, so the sensor presents a high RI sensitivity, which can reach 244.16 nm/RIU in the RI range of1.333–1.3778. Meanwhile it has a low temperature sensitivity of 0.005 nm/°C in the range of 33°C–360°C.展开更多
Two-dimensional(2D)transition-metal dichalcogenide(TMD)monolayers based on become a promising platform to study photonics and optoelectronics.Electrically controlling the excitonic properties of TMD monolayers can be ...Two-dimensional(2D)transition-metal dichalcogenide(TMD)monolayers based on become a promising platform to study photonics and optoelectronics.Electrically controlling the excitonic properties of TMD monolayers can be realized in different devices.In this work,we realize the strong coupling between the excitons of WS_(2)monolayers and a photonic cavity mode in a liquid crystal microcavity.The formed exciton polaritons can be electrically tuned by applying voltage to the microcavity.Our work offers a way to study exciton-polariton manipulation based on TMD monolayers by electrical methods at room temperature.展开更多
基金support from theNational Natural Science Foundation(Grant No.12204111)the National Key Research and Development Program ofChina(Grant No.2023YFA1407100)Shanghai Pilot Pro-gram for Basic Research(Grant No.22JC1403202)。
文摘Microcavity exciton-polaritons,formed by strong light-matter coupling,are essential for realizing Bose-Einstein condensation and low-threshold lasing.Such polaritonic lasing and condensation have been demonstrated in Ⅲ-Ⅴ semiconductors at liquid helium temperatures.However,the complex fabrication of these microcavities and operating temperatures limit their room-temperature practical application.Here,we experimentally realize room-temperature exciton-polariton condensation and polaritonic lasing in a CsPbBr_(3)perovskite planar microcavity fabricated by the pressing process.Angleresolved photoluminescence spectra demonstrate the strong light-matter coupling and the formation of exciton-polaritons in such a pressed microcavity.Above the critical threshold,mass polaritons accumulating at the bottom of dispersion lead to a narrow emission linewidth and pronounced blueshift,further reinforcing the Bose-Einstein condensation and polaritonic lasing in this system.Our results offer a feasible and effective approach to investigate exciton-polariton condensation and polariton lasing at room temperature.
基金Supported by the Program of Natural Science Research of Jiangsu Higher Education Institutions of China under Grant No14KJB 140005
文摘We numerically study the enhancement factor of energy density and absorption efficiency inside the double cylindrical microcavities based on a triple-band metamaterial absorber. The compact single unit cell consists of concentric gold rings with a gold disk in the center and a metallic ground plane separated by a dielectric layer. We demonstrate that the multilayer structure with subwavelength electromagnetic confinement allows 104-105-fold enhancement of the electromagnetic energy density inside the double cavities and contains the most energy of the incoming light. Particularly, the enhancement factor of energy density G shows strong ability of localizing light and some regularity as the change of the thickness of the dielectric slab and dielectric constant. At the normal incidence of electromagnetic radiation, the obtained reflection spectra show that the resonance frequencies of the double microcavities operate in the range of 10-30μm. We also calculate the absorption efficiency C, which can reach 95%, 97% and 95% at corresponding frequency by optimizing the structure＇s geometry parameters. Moreover, the proposed structure will be insensitive to the polarization of the incident wave due to the symmetry of the double cylindrical microcavities. The proposed optical metamaterial is a promising candidate as absorbing elements in scientific and technical applications due to its extreme confinement, multiband absorption and polarization insensitivity.
基金supported by the National Natural Science Foundation of China(Nos.61575168 and 61265009)the Xinjiang Science and Technology Project(No.201412112)
文摘The photoluminescence(PL) properties of porous silicon microcavities(PSMs) in the visible range at room temperature are improved by doping the rare earth ytterbium(Yb) into PSMs prepared by the electrochemical etching method.It is observed that PSMs doped with the rare earth have an emission band around 630 nm.Compared with the single-layer porous silicon(PS) film,the PSMs doped with Yb have narrower and stronger PL spectrum.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 91850117 and 11654003)Beijing Institute of Technology Research Fund Program for Young Scholars
文摘Photonic-plasmonic hybrid microcavities,which possess a higher figure of merit Q/V(the ratio of quality factor to mode volume)than that of pure photonic microcavities or pure plasmonic nano-antennas,play key roles in enhancing light–matter interaction.In this review,we summarize the typical photonic-plasmonic hybrid microcavities,such as photonic crystal microcavities combined with plasmonic nano-antenna,whispering gallery mode microcavities combined with plasmonic nano-antenna,and Fabry–Perot microcavities with plasmonic nano-antenna.The physics and applications of each hybrid photonic-plasmonic system are illustrated.The recent developments of topological photonic crystal microcavities and topological hybrid nano-cavities are also introduced,which demonstrates that topological microcavities can provide a robust platform for the realization of nanophotonic devices.This review can bring comprehensive physical insights of the hybrid system,and reveal that the hybrid system is a good platform for realizing strong light–matter interaction.
文摘By using a Fourier series expansion method combined with Chew＇s perfectly matched layers （PMLs）, we analyze the frequency and quality factor of a micro-cavity on a two-dimensional photonic crystal is analyzed. Compared with the results by the method without PML and finite-difference time-domain （FDTD） based on supercell approximation, it can be shown that by the present method with PMLs, the resonant frequency and the quality factor values can be calculated satisfyingly and the characteristics of the micro-cavity can be obtained by changing the size and permittivity of the point defect in the micro-cavity.
文摘We numerically study the near field enhancement and absorption properties inside the double cylindrical microcavities based on triple-band metamaterial absorber. The compact single unit cell consists of concentric gold rings each with a gold disk in the center, and a metallic ground plane separated by a dielectric layer. At the normal incidence of electromagnetic radiation, the obtained reflection spectra show that the resonance frequencies of the double microcavities are 16.65 THz, 20.65 THz, and 25.65THz, respectively. We also calculate the values of contrast C （C = 1 - Rmin）, which can reach 95%, 97%, and 95% at the corresponding frequencies by optimizing the geometry parameters of structure. Moreover, we demon- strate that the multilayer structure with subwavelength electromagnetic confinement allows 104 -105-fold enhancement of the electromagnetic energy density inside the double cavities, which contains the most energy of the incoming electro- magnetic radiation. Moreover, the proposed structure will be insensitive to the polarization of the incident wave due to the symmetry of the double cylindrical microcavities. The proposed optical metamaterial is a promising candidate as an absorbing element in scientific and technical applications because of its extreme confinement, multiband absorptions, and polarization insensitivity.
文摘We fabricate a-Si/a-SiN_(z) superlattices and a one-dimensional amorphous silicon nitride photonic crystalmicrocavity by plasma enhancement chemical vapor deposition(PECVD).To improve the light-emitting efficiency of the nc-Si/a-SiN_(z)superlattices,which are made from a-Si/a-SiN_(z)superlattices by laser annealing,an nc-Si quantum dot array is inserted into the photonic crystal microcavity.Raman spectroscopy and transmission electron microscopy analysis show that nc-Si with a size of 4nm,which is close to the designed thickness of the a-Si sublayers,is formed in the a-Si sublayers.Owing to microcavity effects,the PL peak of the nc-Si/a-SiN_(z)superlattices embedded in the microcavity is strongly narrowed,and the intensity of the PL is enhanced by two orders of magnitude with respect to the emission of A/2-thick nc-Si/a-SiN_(z)superlattices.Light emission at a cavity-resonant frequency from the nc-Si/a-SiN_(z)superlattices is enhanced while other frequencies are forbidden.This leads to the narrowing of the PL spectrum and enhancement of the intensity.
文摘We present the first findings of the new electrically- and optically-detected magnetic resonance technique [ED electron spin resonance (EDESR) and (ODMR)] which reveal single point defects in the ultra-narrow silicon quantum wells (Si-QW) confined by the superconductor δ-barriers. This technique allows the ESR identification without the application of the external cavity as well as a high frequency source and recorder, with measuring the only magnetoresistance (EDESR) and transmission (ODMR) spectra within frameworks of the excitonic normal-mode coupling (NMC) caused by the microcavities embedded in the Si-QW plane. The new resonant positive magnetoresistance data are interpreted here in terms of the interference transition in the diffusive transport of free holes respectively between the weak antilocalization regime in the region far from the ESR of a paramagnetic point defect located inside or near the conductive channel and the weak localization regime in the nearest region of the ESR of that defect.
基金supported by the Innovation Program for Quantum Science and Technology(No.2021ZD0301200)the National Natural Science Foundation of China(Nos.12222411,11821404 and 12204459)Anhui Provincial Natural Science Foundation(No.2108085QA26).
文摘High-performance optical quantum memories serving as quantum nodes are crucial for the distribution of remote entanglement and the construction of large-scale quantum networks.Notably,quantum systems based on single emitters can achieve deterministic spin–photon entanglement,which greatly simplifies the difficulty of constructing quantum network nodes.Among them,optically interfaced spins embedded in solid-state systems,as atomic-like emitters,are important candidate systems for implementing long-lived quantum memory due to their stable physical properties and robustness to decoherence in scalable and compact hardware.To enhance the strength of light-matter interactions,optical microcavities can be exploited as an important tool to generate high-quality spin–photon entanglement for scalable quantum networks.They can enhance the photon collection probability and photon generation rate of specific optical transitions and improve the coherence and spectral purity of emitted photons.For solid-state systems,open Fabry–Pérot cavities can couple single emitters that are not in proximity to the surface,avoiding significant spectral diffusion induced by the interfaces while maintaining the wide tunability,which enables addressing of multiple single emitters in the frequency and spatial domain within a single device.This review described the characteristics of single emitters as quantum memories with a comparison to atomic ensembles,the cavity-enhancement effect for single emitters and the advantages of different cavities,especially fiber Fabry–Pérot microcavities.Finally,recent experimental progress on solid-state single emitters coupled with fiber Fabry–Pérot microcavities was also reviewed,with a focus on color centers in diamond and silicon carbide,as well as rare-earth dopants.
基金supported by the Shenzhen Fundamental Research Projects(Grant No.JCYJ20160427183259083)the National Natural Science Foundation of China(Grant No.91850204)the Shenzhen Engineering Laboratory on Organic-Inorganic Perovskite Devices
文摘Whispering gallery modes (WGMs) were first discovered for sound waves in the whispering gallery of St Paul’s Cathedral and explained by Rayleigh [1] in 1878. In 1961, Garrett et al.[2] applied the concept of WGMs to optical systems and realized stimulated emissions in Sm2+-doped CaF2 spheres.Since then, WGMs have been widely and intensively studied in a range of micro-sized systems, including microdroplets,microspheres, microtoroids, microdisks, and microtubes.
文摘The coupling between optical and mechanical degrees of freedom has been of broad interest for a long time. However, it is only until recently, with the rapid development of optical mierocavity research, that we are able to manipulate and utilize this coupling process. When a high Q microeavity couples to a mechanical resonator, they can consolidate into an optomeehanieal system. Benefitting from the unique characteristics offered by optomeehanical coupling, this hybrid system has become a promising platform for ultrasensitive sensors to detect displacement, mass, force and acceleration. In this review, we introduce the basic physical concepts of cavity optomechanies, and describe some of the most typical experimental cavity optomechanical systems for sensing applications. Finally, we discuss the noise arising from various sources and show the potentiality of optomechanical sensing towards quantum-noise-limited detection.
基金supported by the National Natural Science Foundation of China(Grant Nos.11734009,11674181,11774182,and 11674184)the 111 Project(Grant No.B07013)+1 种基金PCSIRT(Grant No.IRT 13R29)CAS Interdisciplinary Innovation Team
文摘In this study, we investigate the fabrication of periodically poled lithium niobate(PPLN) microdisk cavities on a chip. These resonators are fabricated from a PPLN film with a 16 μm poling period on insulator using conventional microfabrication techniques.The quality factor of the PPLN microdisk resonators with a 40-μm radius and a 700-nm thickness is 6.7×10~5. Second harmonic generation(SHG) with an efficiency of 2.2×10^(-6) mW(-1) is demonstrated in the fabricated PPLN microdisks. The nonlinear conversion efficiency could be considerably enhanced by optimizing the period and pattern of the poled structure and by improving the cavity quality factors.
基金Acknowledgements The authors sincerely appreciate the help of Shufeng Wang and Yu Li at Peking University and Andong Xia at Institute of Chemistry Chinese Academy of Sciences for their technical support on time-resolved PL. This work was supported by the National Basic Research Program （No. 2013CB932903）, National Natural Science Foundation （Nos. 61275054, 61475035, and 11404289）, Jiangsu Province Science and Technology Support Program （No. BE2016177） and Natural Science Foundation of Zhejiang Province （No. LY17A040011）.
文摘It is essential to develop a single mode operation and improve the performance of lasing in order to ensure practical applicability of microlasers and nanolasers. In this paper, two hexagonal microteeth with varied nanoscaled air-gaps of a ZnO microcomb are used to construct coupled whispering-gallery cavities. This is done to achieve a stable single mode lasing based on Vernier effect without requiring any complicated or sophisticated manipulation to achieve positioning with nanoscale precision. Optical gain and the corresponding ultraviolet lasing performance were improved greatly through coupling with localized surface plasmons of Pt nanoparticles. The ZnO/Pt hybrid microcavities achieved a seven-fold enhancement of intensity of single mode lasing with higher side- mode suppression ratio and lower threshold. The mechanism that led to this enhancement has been described in detail.
文摘Optical microcavities have attracted tremendous interest in both fundamental and applied research in the past few decades, thanks to their small footprint, easy integrability, and high quality factors. Using total internal reflection from a dielectric interface or a photonic band gap in a periodic system, these photonic structures do not rely on conventional metal-coated mirrors to confine light in small volumes, which have brought forth new developments in both classical and quantum optics. This focus issue showcases several such developments and related findings, which may pave the way for the next generation of on-chip photonic devices based on microcavities.
基金National Natural Science Foundation of China(61727801)National Key Research and Development Program of China(2017YFA0303700)+2 种基金China Postdoctoral Science Foundation(2019M6506202019M660605)Beijing Innovation Center for Future Chip。
文摘Quantum state transfer in optical microcavities plays an important role in quantum information processing and is essential in many optical devices such as optical frequency converters and diodes.Existing schemes are effective and realized by tuning the coupling strengths between modes.However,such approaches are severely restricted due to the small amount of strength that can be tuned and the difficulty performing the tuning in some situations,such as in an on-chip microcavity system.Here we propose a novel approach that realizes the state transfer between different modes in optical microcavities by tuning the frequency of an intermediate mode.We show that for typical functions of frequency tuning,such as linear and periodic functions,the state transfer can be realized successfully with different features.To optimize the process,we use the gradient descent technique to find an optimal tuning function for a fast and perfect state transfer.We also showed that our approach has significant nonreciprocity with appropriate tuning variables,where one can unidirectionally transfer a state from one mode to another,but the inverse direction transfer is forbidden.This work provides an effective method for controlling the multimode interactions in on-chip optical microcavities via simple operations,and it has practical applications in all-optical devices.
基金supported by a Grant-in-Aid for Scientific Research from the Ministry of Education,Science,Sports,and Culture of Japan under Grant No.20340080.
文摘We fabricate photonic crystal slab microcavities embedded with GaAs quantum dots by electron beam lithography and droplet epitaxy. The Purcell effect of exciton emission of the quantum dots is confirmed by the micro photoluminescence measurement. The resonance wavelengths, widths, and polarization are consistent with numerical simulation results.
基金National Key R&D Program of China(2017YFA0303703,2016YFA0302500)National Natural Science Foundation of China(NSFC)(61435007,11574144,61475099)+1 种基金Natural Science Foundation of Jiangsu Province,China(BK20150015)Fundamental Research Funds for the Central Universities(021314380086)
文摘By overcoming fabrication limitations, we have successfully fabricated silica toroid microcavities with both large diameter(of 1.88 mm) and ultra-high-Q factor(of 3.3 × 10~8) for the first time, to the best of our knowledge. By employing these resonators, we have further demonstrated low-threshold Kerr frequency combs on a silicon chip,which allow us to obtain a repetition rate as low as 36 GHz. Such a low repetition rate frequency comb can now bedirectly measured through a commercialized optical-electronic detector.
基金National Key Basic Research Program of China(2013CB328701)National Natural Science Foundation of China(NSFC)(61322508,11504270)
文摘Optical whispering gallery microcavities with high-quality factors have shown great potential toward achieveing ultrahigh-sensitivity sensing up to a single molecule or nanoparticle, which raises a huge demand on a deep theoretical insight into the crucial phenomena such as the mode shift, mode splitting, and mode broadening in sensing experiments. Here we propose an intuitive model to analyze these phenomena from the viewpoint of the nanoparticle-induced multiple scattering of the azimuthally propagating mode(APM). The model unveils explicit relations between these phenomena and the phase change and energy loss of the APM when scattered at the nanoparticle; the model also explains the observed polarization-dependent preservation of one resonance and the particle-dependent redshift or blueshift. The model indicates that the particle-induced coupling between the pair of unperturbed degenerate whispering gallery modes(WGMs) and the coupling between the WGMs and the free-space radiation modes, which are widely adopted in current theoretical formalisms, are realized via the reflection and scattering-induced free-space radiation of the APM, respectively, and additionally exhibits the contribution of cross coupling between the unperturbed WGMs and other different WGMs to forming the splittingresonant modes, especially for large particles.
基金supported by the Ministry of Science and Technology of China (MOST) (No. 2015AA043504)the National Natural Science Foundation of China (NSFC) (Nos. 91323301 and 51575053)
文摘We propose a temperature-insensitive refractive index（RI） fiber sensor based on a Mach–Zehnder interferometer. The sensor with high sensitivity and a robust structure is fabricated by splicing a short photonic crystal fiber（PCF） between two single-mode fibers, where two microcavities are formed at both junctions because of the collapse of the PCF air holes. The microcavity with a larger equatorial dimension can excite higher-order cladding modes, so the sensor presents a high RI sensitivity, which can reach 244.16 nm/RIU in the RI range of1.333–1.3778. Meanwhile it has a low temperature sensitivity of 0.005 nm/°C in the range of 33°C–360°C.
基金supported by the National Natural Science Foundation of China(Grant Nos.12174285 and 12474315)support from the National Natural Science Foundation of China(Grant No.62375200)+2 种基金support from the National Natural Science Foundation of China(Grant No.12504372)the China Postdoctoral Science Foundation-Tianjin Joint Support Program(Grant No.2025T003TJ)support from the National Natural Science Foundation of China(Grant No.12404424)。
文摘Two-dimensional(2D)transition-metal dichalcogenide(TMD)monolayers based on become a promising platform to study photonics and optoelectronics.Electrically controlling the excitonic properties of TMD monolayers can be realized in different devices.In this work,we realize the strong coupling between the excitons of WS_(2)monolayers and a photonic cavity mode in a liquid crystal microcavity.The formed exciton polaritons can be electrically tuned by applying voltage to the microcavity.Our work offers a way to study exciton-polariton manipulation based on TMD monolayers by electrical methods at room temperature.
