Showing papers on "Optical microcavity published in 2017"
TL;DR: An alternative sensing scheme is demonstrated, by which the sensitivity of microcavities can be enhanced when operated at non-Hermitian spectral degeneracies known as exceptional points, paves the way for sensors with unprecedented sensitivity.
Abstract: Sensors play an important part in many aspects of daily life such as infrared sensors in home security systems, particle sensors for environmental monitoring and motion sensors in mobile phones. High-quality optical microcavities are prime candidates for sensing applications because of their ability to enhance light-matter interactions in a very confined volume. Examples of such devices include mechanical transducers, magnetometers, single-particle absorption spectrometers, and microcavity sensors for sizing single particles and detecting nanometre-scale objects such as single nanoparticles and atomic ions. Traditionally, a very small perturbation near an optical microcavity introduces either a change in the linewidth or a frequency shift or splitting of a resonance that is proportional to the strength of the perturbation. Here we demonstrate an alternative sensing scheme, by which the sensitivity of microcavities can be enhanced when operated at non-Hermitian spectral degeneracies known as exceptional points. In our experiments, we use two nanoscale scatterers to tune a whispering-gallery-mode micro-toroid cavity, in which light propagates along a concave surface by continuous total internal reflection, in a precise and controlled manner to exceptional points. A target nanoscale object that subsequently enters the evanescent field of the cavity perturbs the system from its exceptional point, leading to frequency splitting. Owing to the complex-square-root topology near an exceptional point, this frequency splitting scales as the square root of the perturbation strength and is therefore larger (for sufficiently small perturbations) than the splitting observed in traditional non-exceptional-point sensing schemes. Our demonstration of exceptional-point-enhanced sensitivity paves the way for sensors with unprecedented sensitivity.
1,403 citations
TL;DR: This review focuses on single nanoparticle detection using optical whispering gallery microcavities and photonic crystal microc Cavities, both of which have been developing rapidly over the past few years.
Abstract: Detection of nanoscale objects is highly desirable in various fields such as early-stage disease diagnosis, environmental monitoring and homeland security. Optical microcavity sensors are renowned for ultrahigh sensitivities due to strongly enhanced light-matter interaction. This review focuses on single nanoparticle detection using optical whispering gallery microcavities and photonic crystal microcavities, both of which have been developing rapidly over the past few years. The reactive and dissipative sensing methods, characterized by light-analyte interactions, are explained explicitly. The sensitivity and the detection limit are essentially determined by the cavity properties, and are limited by the various noise sources in the measurements. On the one hand, recent advances include significant sensitivity enhancement using techniques to construct novel microcavity structures with reduced mode volumes, to localize the mode field, or to introduce optical gain. On the other hand, researchers attempt to lower the detection limit by improving the spectral resolution, which can be implemented by suppressing the experimental noises. We also review the methods of achieving a better temporal resolution by employing mode locking techniques or cavity ring up spectroscopy. In conclusion, outlooks on the possible ways to implement microcavity-based sensing devices and potential applications are provided.
250 citations
TL;DR: The broad spectral tunability via a simple variation of the cavity thickness makes this innovative, flexible and potentially visibly transparent device principle highly suitable for integrated low-cost spectroscopic near-infrared photodetection.
Abstract: Blending organic electron donors and acceptors yields intermolecular charge-transfer states with additional optical transitions below their optical gaps. In organic photovoltaic devices, such states play a crucial role and limit the operating voltage. Due to its extremely weak nature, direct intermolecular charge-transfer absorption often remains undetected and unused for photocurrent generation. Here, we use an optical microcavity to increase the typically negligible external quantum efficiency in the spectral region of charge-transfer absorption by more than 40 times, yielding values over 20%. We demonstrate narrowband detection with spectral widths down to 36 nm and resonance wavelengths between 810 and 1,550 nm, far below the optical gap of both donor and acceptor. The broad spectral tunability via a simple variation of the cavity thickness makes this innovative, flexible and potentially visibly transparent device principle highly suitable for integrated low-cost spectroscopic near-infrared photodetection. Interfaces of organic donor-acceptor blends provide intermolecular charge-transfer states with red-shifted but weak absorption. By introducing an optical micro-cavity; Siegmundet al., enhance their photoresponse to achieve narrowband NIR photodetection with broad spectral tunability.
181 citations
TL;DR: This work demonstrates thermalization of SWCNT polaritons, exciton-polariton pumping rates ∼104 times higher than in current organic polariton devices, direct control over the coupling strength (Rabi splitting) via the applied gate voltage, and a tenfold enhancement of polaritonic over excitonic emission.
Abstract: The exciton-polaritons formed using carbon nanotube field-effect transistors strongly coupled to an optical microcavity can sustain electrical pumping under high current densities.
108 citations
TL;DR: In this paper, the fluorescence of individual silicon-vacancy centers in nanodiamonds is coupled to a tunable optical microcavity to demonstrate a single-photon source with high efficiency, increased emission rate, and improved spectral purity compared to the intrinsic emitter properties.
Abstract: Single-photon sources are an integral part of various quantum technologies, and solid-state quantum emitters at room temperature appear to be a promising implementation. We couple the fluorescence of individual silicon-vacancy centers in nanodiamonds to a tunable optical microcavity to demonstrate a single-photon source with high efficiency, increased emission rate, and improved spectral purity compared to the intrinsic emitter properties. We use a fiber-based microcavity with a mode volume as small as 3.4 lambda(3) and a quality factor of 1.9 x 10(4) and observe an effective Purcell factor of up to 9.2. Furthermore, we study modifications of the internal rate dynamics and propose a rate model that closely agrees with the measurements. We observe lifetime changes of up to 31%, limited by the finite quantum efficiency of the emitters studied here. With improved materials, our achieved parameters predict single-photon rates beyond 1 GHz.
90 citations
TL;DR: In this paper, an optical resonator was used to create enhanced coupling between light and a single organic dye molecule, which is an essential ingredient for future quantum networks, and a new experiment was conducted to evaluate the effect of the resonator on the interaction between photons and atoms.
Abstract: Efficient interactions between photons and atoms are an essential ingredient for future quantum networks. A new experiment uses an optical resonator to create enhanced coupling between light and a single organic dye molecule.
70 citations
TL;DR: The synergistic nanoantenna-microcavity hybrid strategy opens new opportunities for further enhancing nanoscale light-matter interactions to benefit numerous areas such as nonlinear optics, nanolasers, plasmonic hot carrier technology, and surface-enhanced Raman and infrared absorption spectroscopies.
Abstract: Nanoantennas offer the ultimate spatial control over light by concentrating optical energy well below the diffraction limit, whereas their quality factor (Q) is constrained by large radiative and dissipative losses. Dielectric microcavities, on the other hand, are capable of generating a high Q-factor through an extended photon storage time but have a diffraction-limited optical mode volume. Here we bridge the two worlds, by studying an exemplary hybrid system integrating plasmonic gold nanorods acting as nanoantennas with an on-resonance dielectric photonic crystal (PC) slab acting as a low-loss microcavity and, more importantly, by synergistically combining their advantages to produce a much stronger local field enhancement than that of the separate entities. To achieve this synergy between the two polar opposite types of nanophotonic resonant elements, we show that it is crucial to coordinate both the dissipative loss of the nanoantenna and the Q-factor of the low-loss cavity. In comparison to the ante...
67 citations
TL;DR: In this paper, a Fabry-Perot microcavity enclosing a thin diamond membrane at cryogenic temperatures is proposed to enhance resonant emission of single nitrogen-vacancy centers by allowing spectral and spatial tuning while preserving the optical properties observed in bulk diamond.
Abstract: We report on the fabrication and characterization of a Fabry-Perot microcavity enclosing a thin diamond membrane at cryogenic temperatures. The cavity is designed to enhance resonant emission of single nitrogen-vacancy centers by allowing spectral and spatial tuning while preserving the optical properties observed in bulk diamond. We demonstrate cavity finesse at cryogenic temperatures within the range of F ¼ 4000–12 000 and find a sub-nanometer cavity stability. Modeling shows that coupling nitrogen-vacancy centers to these cavities could lead to an increase in remote entanglement success rates by three orders of magnitude.
62 citations
TL;DR: In this article, the authors summarized the latest development of ZnO optical cavity based microlasers, mainly including Fabry-Perot mode lasers and whispering gallery mode lasers, and discussed the synthesis and optical studies of different morphologies were discussed in detail, and considered that the research focus in the near future would include new nanotechnology and physical effects, such as nano/micro fabrication, surface plasmon enhancement, and quantum dot coupling, which may result in new and interesting physical phenomena.
48 citations
TL;DR: A novel design for a high-gain and high-speed (up to terahertz) photonic transistor and its counterpart in the quantum limit based on a linear optical effect: giant Faraday rotation induced by a single electronic spin in a single-sided optical microcavity provides a solid-state platform ideal for all-optical networks and quantum networks.
Abstract: The future Internet is very likely the mixture of all-optical Internet with low power consumption and quantum Internet with absolute security guaranteed by the laws of quantum mechanics. Photons would be used for processing, routing and com-munication of data, and photonic transistor using a weak light to control a strong light is the core component as an optical analogue to the electronic transistor that forms the basis of modern electronics. In sharp contrast to previous all-optical tran-sistors which are all based on optical nonlinearities, here I introduce a novel design for a high-gain and high-speed (up to terahertz) photonic transistor and its counterpart in the quantum limit, i.e., single-photon transistor based on a linear optical effect: giant Faraday rotation induced by a single electronic spin in a single-sided optical microcavity. A single-photon or classical optical pulse as the gate sets the spin state via projective measurement and controls the polarization of a strong light to open/block the photonic channel. Due to the duality as quantum gate for quantum information processing and transistor for optical information processing, this versatile spin-cavity quantum transistor provides a solid-state platform ideal for all-optical networks and quantum networks.
42 citations
TL;DR: Dibenzo[hi,st]ovalene (DBOV)-a quasi-zero-dimensional "nanographene"-displays strong, narrow, and well-defined optical-absorption transitions at room temperature, and strong coupling of the 0 → 0' electronic transition to a confined cavity mode is demonstrated.
Abstract: Dibenzo[hi,st]ovalene (DBOV)-a quasi-zero-dimensional "nanographene"-displays strong, narrow, and well-defined optical-absorption transitions at room temperature. On placing a DBOV-doped polymer film into an optical microcavity, we demonstrate strong coupling of the 0 → 0' electronic transition to a confined cavity mode, with a coupling energy of 126 meV. Photoluminescence measurements indicate that the polariton population is distributed at energies approximately coincident with the emission of the DBOV, indicating a polariton population via an optical pumping mechanism.
Abstract: We report the efficient coherent photon scattering from a semiconductor quantum dot embedded in a pillar microcavity. We show that a surface acoustic wave can periodically modulate the energy levels of the quantum dot but has a negligible effect on the cavity mode. The scattered narrow-band laser is converted into a pulsed single-photon stream, displaying an anti-bunching dip characteristic of single-photon emission. Multiple phonon sidebands are resolved in the emission spectrum, due to the absorption and emission of vibrational quanta in each scattering event.
TL;DR: Measurements of first-order spatial correlations in a harmonically trapped two-dimensional photon gas below, at and above the critical particle number for Bose–Einstein condensation are reported, using interferometric measurements of the emission of a dye-filled optical microcavity.
Abstract: Phase transitions between different states of matter can profoundly modify the order in physical systems, with the emergence of ferromagnetic or topological order constituting important examples. Correlations allow the quantification of the degree of order and the classification of different phases. Here we report measurements of first-order spatial correlations in a harmonically trapped two-dimensional photon gas below, at and above the critical particle number for Bose–Einstein condensation, using interferometric measurements of the emission of a dye-filled optical microcavity. For the uncondensed gas, the transverse coherence decays on a length scale determined by the thermal de Broglie wavelength of the photons, which shows the expected scaling with temperature. At the onset of Bose–Einstein condensation, true long-range order emerges, and we observe quantum statistical effects as the thermal wave packets overlap. The excellent agreement with equilibrium Bose gas theory prompts microcavity photons as promising candidates for studies of critical scaling and universality in optical quantum gases. Phase transitions in quantum matter are related to correlation effects and they can change the ordering of material. Here the authors measure the first-order spatial correlation and the de Broglie wavelength for both thermal and condensed form of a photonic Bose gas in a dye-filled optical microcavity.
TL;DR: This work coupling an individual nanotube to a tunable optical microcavity is shown to be a valuable resource to enlarge the tuning range of the single-photon source while keeping an excellent exciton-phonon coupling efficiency and spectral purity.
Abstract: Condensed-matter emitters offer enriched cavity quantum electrodynamical effects due to the coupling to external degrees of freedom. In the case of carbon nanotubes, a very peculiar coupling between localized excitons and the one-dimensional acoustic phonon modes can be achieved, which gives rise to pronounced phonon wings in the luminescence spectrum. By coupling an individual nanotube to a tunable optical microcavity, we show that this peculiar exciton–phonon coupling is a valuable resource to enlarge the tuning range of the single-photon source while keeping an excellent exciton-photon coupling efficiency and spectral purity. Using the unique flexibility of our scanning fiber cavity, we are able to measure the efficiency spectrum of the very same nanotube in the Purcell regime for several mode volumes. Whereas this efficiency spectrum looks very much like the free-space luminescence spectrum when the Purcell factor is small (large mode volume), we show that the deformation of this spectrum at lower mod...
TL;DR: In this paper, the authors demonstrate that gold nanorods coated with a nonlinear material reduce the comb generation threshold when decorated on the surface of the resonant cavities, and the enhancement mechanism is explored with finite element method modeling and can be explained in terms of photonic-plasmonic mode hybridization.
Abstract: Optical frequency combs are high repetition rate, broad spectral bandwidth coherent light sources. These devices have numerous applications in many fields, ranging from fundamental science to defense. Recently, low-threshold and small-footprint frequency combs have been demonstrated using ultrahigh quality factor (Q) whispering gallery mode resonant cavities. The majority of research in cavity-based combs has focused on optimizing the Q. An alternative strategy is to engineer the cavity material to enhance the underlying nonlinear process for comb generation. In this work, we demonstrate that gold nanorods coated with a nonlinear material reduce the comb generation threshold when decorated on the surface of the resonant cavities. The enhancement mechanism is explored with finite element method modeling and can be explained in terms of photonic–plasmonic mode hybridization. A comb span of ∼300 nm in the near-IR range is observed with incident intensity <2 GW cm–2. The required threshold for parametric osci...
TL;DR: In this article, the quantum back action associated with the resonantly enhanced optical cross-and self-phase modulation results in the standard quantum limit of the angle random walk of the gyroscope.
TL;DR: In this paper, a thin cylindrical slot etched into a disk shape optical microcavity (MC) aiming for sensing biomaterials in a label-free style is proposed and investigated.
Abstract: In this paper, we propose and investigate a thin cylindrical slot etched into a disk shape optical microcavity (MC) aiming for sensing biomaterials in a label-free style. Supporting whispering gallery modes (WGMs), with remarkably large quality factor to modal volume ratio (Q/Vm) of the optical MC structures that penetrate in the slot region, enables us to perform sensing. Three different geometries for the side walls of host microdisk cavities, including vertical, 60° wedged, and half-circular cross section, are selected for investigations. In each individual case, the radial position, width, and height of the thin cylindrical slot are varied. The electromagnetic (EM) field intensity distributions (mode mapping profiles) of the WGMs show funneling of the intensified fields into the slot area that possessing nearly the same high Q values. Tuning the slot position, width, and depth for a suitably chosen WGM, sensing could be optimized for different biomaterials. Sensitivity value as high as 75 nm/RIU is calculated for the half-circular side wall microdisk. The proposed WGM-based slotted microdisk, as a state-of-the-art device which can operate, such as lab-on-chip structure, would function as a sensitive biosensor, even down to the single biomolecule levels.
TL;DR: In this article, the effect of interplay between the proposed resonance interactions and the incorporated non-Hermiticity in the microcavity is analyzed drawing a special attention to the existence of hidden singularities, namely exceptional points (EPs), where at least two coupled resonances coalesce.
Abstract: We report a specially configured open optical microcavity, imposing a spatially imbalanced gain–loss profile, to host an exclusively proposed next-nearest-neighbor resonance coupling scheme. Adopting the scattering matrix (S-matrix) formalism, the effect of interplay between such proposed resonance interactions and the incorporated non-Hermiticity in the microcavity is analyzed drawing a special attention to the existence of hidden singularities, namely exceptional points (EPs), where at least two coupled resonances coalesce. We establish adiabatic flip-of-state phenomenon of the coupled resonances in the complex frequency plane (k-plane), which is essentially an outcome of the fact that the respective EP is being encircled in the system parameter plane. Encountering such multiple EPs, the robustness of flip-of-states phenomena has been analyzed via continuous tuning of coupling parameters along a special hidden singular line which connects all the EPs in the cavity. Such a numerically devised cavity, incorporating the exclusive next neighbor coupling scheme, has been designed for the first time to study the unconventional optical phenomena in the vicinity of EPs.
TL;DR: In this article, the formation of a special hidden singular line connecting multiple second-order hidden singular points, in a non-uniformly pumped degenerate optical microcavity, is reported.
Abstract: Using scattering matrix formalism, we report the formation of a special hidden singular line connecting multiple second-order hidden singular points, in a non-uniformly pumped degenerate optical microcavity. Such singularities are known as exceptional points (EPs), and the line is proposed as an exceptional line. Exploring the unconventional behavior of cavity resonances created by a spatially imbalanced gain–loss profile, we have established the adiabatic state-flipping mechanism of coupled resonances encountering such EPs. Various interesting encircling situations, incorporating smooth as well as fluctuating variations of the control parameters, have been analyzed. We exploit the above scheme for the first time, to the best of our knowledge, to analyze the optical performance and stability of the cascaded flip-of-state phenomenon assisted by successive encirclement of either single or multiple singularities following the exceptional line in the context of optical mode converters.
01 Jul 2017-Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology
TL;DR: In this article, a tool with a nose radius of 0.01mm was used for cylindrical turning of a single-crystal calcium fluoride (CaF2) microcavity.
Abstract: An optical microcavity, which stores light at a certain spot, is an essential component to realize all-optical signal processing. Single-crystal calcium fluoride (CaF2) theoretically shows a high Q-factor which is a desirable optical property. The CaF2 microcavity can only be manufactured by ultra-precision cylindrical turning (UPCT). The authors have studied UPCT of CaF2 and shown the influence of crystal anisotropy and tool geometry on surface roughness and subsurface damage. The study indicated that a smaller nose radius of the cutting tool led to shallower subsurface damage. Thus, it is inferred that a smaller nose radius compared to the previous nose radius (0.05 mm) can further reduce subsurface damage. Nevertheless, the mechanism that causes a difference in subsurface damage due to crystal anisotropy is not sufficiently clear. The influence of subsurface damage on microcavity performance is still unclear. In this study, the UPCT of CaF2 was conducted using a tool with a nose radius of 0.01 mm. The subsurface damage was investigated by transmission electron microscope (TEM) observation from the viewpoint of the change in crystal lattice arrangement. In our previous study, fast Fourier transfer (FFT) analysis was used for confirmation of change of crystal structure. In this study, FFT analysis was also used to quantitatively evaluate the depth of subsurface damage. In addition, inverse fast Fourier transfer (IFFT) was used to analyze change of crystal lattice arrangement clearly, which enables discussion of the influence of slip systems. Finally, optical microcavities are manufactured without any crack, and the influence of subsurface damage on microcavity performance is experimentally evaluated using a wavelength tunable laser and power meter.
TL;DR: Modulation bandwidth enhancements are investigated for coupled twin-square microcavity lasers due to photon-photon resonance effect, and numerical simulations are conducted for large signal modulation with improved eye-diagrams at 40 Gbit/s.
Abstract: Modulation bandwidth enhancements are investigated for coupled twin-square microcavity lasers due to photon-photon resonance effect. For a coupled twin-square microcavity laser with the square side length of 20 μm, we demonstrate the increase of 3-dB modulation bandwidth from 9.6 GHz to 19.5 GHz, by adjusting the resonance mode wavelength interval between two square microcavities. The enhanced modulation bandwidth is explained by rate equation analysis, and numerical simulations are conducted for large signal modulation with improved eye-diagrams at 40 Gbit/s.
TL;DR: High localization of the excitons in the VCSEL gain layer can enhance their collective emission properties with Langmuir-Blodgett deposition presenting a paradigm for engineering the high gain layers on the molecular level.
Abstract: The ability to confine excitons within monolayers has led to fundamental investigations of nonradiative energy transfer, super-radiance, strong light–matter coupling, high-efficiency light-emitting diodes, and recently lasers in lateral resonator architectures. Vertical cavity surface emitting lasers (VCSELs), in which lasing occurs perpendicular to the device plane, are critical for telecommunications and large-scale photonics integration, however strong optical self-absorption and low fluorescence quantum yields have thus far prevented coherent emission from a monolayer microcavity device. Here we show lasing from a monolayer VCSEL using a single molecule thick film of amphiphilic fluorescent dye, assembled via Langmuir–Blodgett deposition, as the gain layer. Threshold was observed when 5% of the molecules were excited (4.4 μJ/cm2). At this level of excitation, the optical gain in the monolayer exceeds 1056 cm–1. High localization of the excitons in the VCSEL gain layer can enhance their collective emis...
TL;DR: In this paper, a numerical analysis of Fabry-Perot optical cavities with Gaussian-shape mirrors formed between tips of optical fibers is presented, and the effect of the mode mixing on the coherent atom-cavity coupling as well as the mode matching between the cavity and a single-mode optical fiber is investigated.
Abstract: We present a systematic numerical study of Fabry-Perot optical cavities with Gaussian-shape mirrors formed between tips of opticalfibers. Such cavities can be fabricated by laser machining of fiber tips and are promising systems for achieving strong coupling between atomic particles and an optical field as required for quantum information applications. Using a mode mixing matrix method, we analyze the cavity optical eigenmodes and corresponding losses depending on a range of cavity-shape parameters, such as mirror radius of curvature, indentation depth and cavity length. The Gaussian shape of the mirrors causes mixing of optical modes in the cavity. We investigate the effect of the mode mixing on the coherent atom-cavity coupling as well as the mode matching between the cavity and a single-mode optical fiber. While the mode mixing is associated with increased cavity losses, it can also lead to an enhancement of the local optical field. We demonstrate that around the resonance between the fundamental and 2nd order Laguerre-Gaussian modes of the cavity it is possible to obtain 50% enhancement of the atom-cavity coupling at the cavity center while still maintaining low cavity losses and high cavity-fiber optical coupling.
TL;DR: In this article, the authors report on the modeling, simulation, and experimental demonstration of complete mode crossings of Fano resonances within chip-integrated micro-resonators, and exploit such tunability to continuously probe the coupling between different families of quasi-degenerate modes that exhibit asymmetric Fano interactions.
Abstract: We report on the modeling, simulation, and experimental demonstration of complete mode crossings of Fano resonances within chip-integrated microresonators. The continuous reshaping of resonant line shapes is achieved via nonlinear thermo-optical tuning when the cavity-coupled optical pump is partially absorbed by the material. The locally generated heat then produces a thermal field, which influences the spatially overlapping optical modes, allowing us to alter the relative spectral separation of resonances. Furthermore, we exploit such tunability to continuously probe the coupling between different families of quasi-degenerate modes that exhibit asymmetric Fano interactions. As a particular case, we demonstrate a complete disappearance of one of the modal features in the transmission spectrum as predicted by Fano [Phys. Rev.124, 1866 (1961)PHRVAO0031-899X10.1103/PhysRev.124.1866]. The phenomenon is modeled as a third-order nonlinearity with a spatial distribution that depends on the stored optical field and thermal diffusion within the resonator. The performed nonlinear numerical simulations are in excellent agreement with the experimental results, which confirm the validity of the developed theory.
TL;DR: In this article, a Fabry-Perot (FP) microcavity is constructed with one micro-concave mirror and another planar mirror facing each other to form a stable cavity.
Abstract: We present the generation of optofluidic lasers in a Fabry-Perot (FP) microcavity with low pumping threshold. The FP microcavity is constructed with one micro-concave mirror and another planar mirror facing each other to form a stable cavity. The two mirrors are coated with dielectric layers with reflectivity ≥99.9%. Laser behaviors are tested with gain medium, Rhodamine 6 G (R6G), dissolved in ethanol and ion water, respectively; a lowest pumping threshold as small as 0.13 μJ/mm2 is achieved in the ethanol solution, corresponding to a theoretically calculated quality value Q0 about 4×105. Meanwhile experimental results demonstrates that the lowest concentration of dye medium that can emit laser signal in the FP microcavity is 3 μM.
TL;DR: In this paper, the authors have simulated the transmission spectrum of a microcavity in which the Bragg reflectors are made with silica (SiO 2 ) and yttria (Y 2 O 3 ) and the defect layer is made with TGG (Tb 3 Ga 5 O 12 ).
TL;DR: Using a quantum electrodynamical (QED) treatment, it is demonstrated that the χ(3) cascading contributions can be greatly suppressed, and it is shown that up to ∼99.5% suppression of the cascading signal is possible.
Abstract: Nonlinear optical signals in the condensed phase are often accompanied by sequences of lower-order processes, known as cascades, which share the same phase matching and power dependence on the incoming fields and are thus hard to distinguish. The suppression of cascading in order to reveal the desired nonlinear signal has been a major challenge in multidimensional Raman spectroscopy, that is, the χ(5) signal being masked by cascading signals given by a product of two χ(3) processes. Because cascading originates from the exchange of a virtual photon between molecules, it can be manipulated by performing the experiment in an optical microcavity which modifies the density of radiation field modes. Using a quantum electrodynamical (QED) treatment, we demonstrate that the χ(3) cascading contributions can be greatly suppressed. By optimizing the cavity size and the incoming pulse directions, we show that up to ∼99.5% suppression of the cascading signal is possible.
TL;DR: The device with the Ta2O5/Au/MoO3 electrode, fabricated at an optimum condition based on the simulation result by calculating the photon flux, exhibited 52% enhancement in light out-coupling efficiency at 1000 cd/m2 and improved color stability with the viewing angle, having near-Lambertian emission.
Abstract: We demonstrate enhanced light out-coupling efficiency of organic light-emitting diodes by applying a multilayer stacked electrode structure consisting of fast and cost-effective sol-gel processed tantalum pentoxide (Ta2O5), thin layer of Au and molybdenum trioxide (MoO3). The application of the Ta2O5/Au/MoO3 electrode can modulate the optical characteristics of the device due to the optical microcavity effect. The refractive index of the sol-gel processed Ta2O5 thin film varied depending on the annealing temperature and reached a maximum at 400 °C (n = 2.2 at 512 nm). The influence of the refractive index of the Ta2O5 layer and the thickness of the multilayer electrode stack on the optical microcavity effect was systematically investigated. The device with the Ta2O5/Au/MoO3 electrode, fabricated at an optimum condition based on the simulation result by calculating the photon flux, exhibited 52% enhancement in light out-coupling efficiency at 1000 cd/m2 and improved color stability with the viewing angle, having near-Lambertian emission.
TL;DR: A suspended whispering gallery mode microdisk with a hole pierced through its surface made up of Rhodamine B-doped resin is reported, which achieves highly directional emission of single-mode lasing with a far field divergence angle of about 10 deg, and its high Q factor exceeds 2.6×103.
Abstract: In this Letter, we report a suspended whispering gallery mode microdisk with a hole pierced through its surface. The novel disk is made up of Rhodamine B-doped resin, which is fabricated by femtosecond laser direct writing technology. The pierced microcavity achieves highly directional emission of single-mode lasing with a far field divergence angle of about 10 deg, and its high Q factor exceeds 2.6×103. The excellent properties are confirmed by numerical simulation based on the finite-difference time-domain method. The effect of the pierced hole on the microcavity performance is discussed in detail. The method is easy to implement and has a guiding significance for improving the characteristics of an existing microcavity by simple modification.
TL;DR: In this paper, the authors demonstrate arbitrary laser frequency detuning control in an optical microcavity, utilizing auxiliary laser heating method to simplify cavity thermal behavior, and demonstrate novel Kerr comb dynamics and flexible manipulation of dissipative cavity solitons.
Abstract: We demonstrate arbitrary laser frequency detuning control in an optical microcavity, utilizing auxiliary laser heating method to simplify cavity thermal behavior. Novel Kerr comb dynamics and flexible manipulation of dissipative cavity solitons are reported.