Showing papers on "Optical microcavity published in 2016"
TL;DR: An approach that utilizes the optical spring effect in a high-Q coherent optomechanical oscillator to dramatically enhance the sensing resolution by orders of magnitude compared with conventional approaches is proposed, allowing us to detect single bovine serum albumin proteins with a molecular weight of 66 kDa at a signal-to-noise ratio of 16.8.
Abstract: Label-free bio-sensing is a critical functionality underlying a variety of health- and security-related applications. Micro-/nano-photonic devices are well suited for this purpose and have emerged as promising platforms in recent years. Here we propose and demonstrate an approach that utilizes the optical spring effect in a high-Q coherent optomechanical oscillator to dramatically enhance the sensing resolution by orders of magnitude compared with conventional approaches, allowing us to detect single bovine serum albumin proteins with a molecular weight of 66 kDa at a signal-to-noise ratio of 16.8. The unique optical spring sensing approach opens up a distinctive avenue that not only enables biomolecule sensing and recognition at individual level, but is also of great promise for broad physical sensing applications that rely on sensitive detection of optical cavity resonance shift to probe external physical parameters. Detection of a single nanoparticle or molecule is essential for many applications. Here, Yu et al.demonstrate the use of an optical cavity with optomechanical oscillation to detect single bovine serum albumin proteins, with potential for studying mechanical properties and interactions of individual molecules.
180 citations
TL;DR: This system marks the first demonstration of polariton hybridization between a solid and solvent molecules and can open new paths toward chemical reaction modification and energy transfer studies in the mid-infrared spectral range.
Abstract: Hybridized polaritons are generated by simultaneously coupling two vibrational modes of two different organic materials to the resonance of a low-loss infrared optical microcavity. A thin film of poly methyl methacrylate with solvent molecules of dimethylformamide trapped inside provided two spectrally narrow, closely spaced carbonyl stretches with absorption peaks at 1731 and 1678 cm–1. Situating this film in a microcavity based on Ge/ZnS distributed Bragg reflector mirrors produced three distinct polariton branches in the dispersion relation due to hybridization of the vibrational resonances. Two anticrossings were observed with Rabi splittings of 9.6 and 5.2 meV, between the upper-to-middle and middle-to-lower polariton branches, respectively. This system marks the first demonstration of polariton hybridization between a solid and solvent molecules and can open new paths toward chemical reaction modification and energy transfer studies in the mid-infrared spectral range.
77 citations
TL;DR: In this article, the dissipative interaction in an optical microcavity of high quality factor allows the detection of single nanoparticles, even when the real part of an analyte's polarizability approaches zero.
Abstract: Ultrasensitive detection of nanoscale particles has applications in important fields ranging from environmental monitoring to analysis of viral structures. The authors show that the dissipative interaction in an optical microcavity of high quality factor allows the detection of single nanoparticles, even when the real part of an analyte's polarizability approaches zero. This innovative approach presents a significant step towards practical optical sensors for use in physics, analytical chemistry, environmental science, and molecular biology.
76 citations
TL;DR: Optical microcavities have attracted strong research interests, for their unique property of confining photons for a long time in small volumes, which significantly enhances light-matter interaction as discussed by the authors.
Abstract: Optical microcavities have attracted strong research interests,for their unique property of confining photons for a long time in small volumes,which significantly enhances light–matter interaction[1].In recent decades,various fabrication techniques of microcavities with higher quality factors(Q)and smaller mode volumes(V_m)have been developed,pushing forward studies from fundamental physics to functional photonics devices.Microcavity optomechanics provides an ideal platform for exploring the quantum nature of macroscopic objects[2],quantum
70 citations
TL;DR: Benefit from the very narrow spectrum of QDs and the low absorption of silver electrodes, the potential of microcavity effect can be fully exploited in TQLEDs.
Abstract: The microcavity effect in top-emitting quantum dot light-emitting diodes (TQLEDs) is theoretically and experimentally investigated. By carefully optimizing the cavity length, the thickness of the top Ag electrode and the thickness of the capping layer, very bright and efficient TQLEDs with external quantum efficiency (EQE) of 12.5% are demonstrated. Strong dependence of luminance and efficiency on cavity length is observed, in good agreement with theoretical calculation. By setting the normal-direction resonant wavelength around the peak wavelength of the intrinsic emission, highest luminance of 112 000 cd/m2 (at a driving voltage of 7 V) and maximum current efficiency of 27.8 cd/A are achieved, representing a 12-fold and a 2.1-fold enhancement compared to 9000 cd/m2 and 13.2 cd/A of the conventional bottom emitting devices, respectively, whereas the highest EQE of 12.5% is obtained by setting the resonant wavelength 30 nm longer than the peak wavelength of the intrinsic emission. Benefit from the very na...
69 citations
TL;DR: In this article, 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 as 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 $1.9\times 10^4$ and observe an effective Purcell factor of up to 9.2. We furthermore 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.
64 citations
TL;DR: Wilson et al. as mentioned in this paper proposed a single-chip optonanomechanical transducer based on a high-stress Si3N4 nanobeam monolithically integrated into the evanescent near field of SiO2 microdisk cavity.
Abstract: Placing a nanomechanical object in the evanescent near field of a high-Q optical microcavity gives access to strong gradient forces and quantum-limited displacement readout, offering an attractive platform for both precision sensing technology and basic quantum optics research. Robustly implementing this platform is challenging, however, as it requires integrating optically smooth surfaces separated by less than or similar to lambda/10. Here we describe an exceptionally high-cooperativity, single-chip optonanomechanical transducer based on a high-stress Si3N4 nanobeam monolithically integrated into the evanescent near field of SiO2 microdisk cavity. Employing a vertical integration technique based on planarized sacrificial layers, we realize beam-disk gaps as little as 25 nm while maintaining mechanical Qf > 10(12) Hz and intrinsic optical Q similar to 10(7). The combination of low loss, small gap, and parallel-plane geometry results in radio-frequency flexural modes with vacuum optomechanical coupling rates of 100 kHz, single-photon cooperativities in excess of unity, and large zero-point frequency (displacement) noise amplitudes of 10 kHz (fm) / root Hz. In conjunction with the high power-handling capacity of SiO2 and low extraneous substrate noise, the transducer performs particularly well as a sensor, with recent deployment in a 4-K cryostat realizing a displacement imprecision 40 dB below that at the standard quantum limit (SQL) and an imprecision-backaction product < 5h [Wilson et al., Nature (London) 524, 325 (2015)]. In this report, we provide a comprehensive description of device design, fabrication, and characterization, with an emphasis on extending Heisenberg-limited readout to room temperature. Towards this end, we describe a roomtemperature experiment in which a displacement imprecision 32 dB below that at the SQL and an imprecision-backaction product < 60h is achieved. Our results extend the outlook for measurement-based quantum control of nanomechanical oscillators and suggest an alternative platform for functionally integrated "hybrid" quantum optomechanics.
49 citations
TL;DR: The potential of alternative sensing mechanisms and hybrid sensing devices for more sensitive and rapid analyses are discussed, including advancements in biosensing and other applications of optical sensors.
Abstract: Optical resonator sensors are an emerging class of analytical technologies that use recirculating light confined within a microcavity to sensitively measure the surrounding environment. Bolstered by advances in microfabrication, these devices can be configured for a wide variety of chemical or biomolecular sensing applications. We begin with a brief description of optical resonator sensor operation, followed by discussions regarding sensor design, including different geometries, choices of material systems, methods of sensor interrogation, and new approaches to sensor operation. Throughout, key developments are highlighted, including advancements in biosensing and other applications of optical sensors. We discuss the potential of alternative sensing mechanisms and hybrid sensing devices for more sensitive and rapid analyses. We conclude with our perspective on the future of optical microcavity sensors and their promise as versatile detection elements within analytical chemistry.
49 citations
Patent•
IBM1
TL;DR: In this article, an optoelectronic integrated circuit for coupling light to or from an optical waveguide formed in an optical device layer in a near-normal angle to that layer is presented.
Abstract: An optoelectronic integrated circuit for coupling light to or from an optical waveguide formed in an optical device layer in a near-normal angle to that layer. In an embodiment, the integrated circuit comprises a semiconductor body including a metal-dielectric stack, an optical device layer, a buried oxide layer and a semiconductor substrate arranged in series between first and second opposite sides of the semiconductor body. At least one optical waveguide is formed in the optical device layer for guiding light in a defined plane in that device layer. Diffractive coupling elements are disposed in the optical device layer to couple light from the waveguide toward the second surface of the semiconductor body at a near-normal angle to the defined plane in the optical device layer. In an embodiment, an optical fiber is positioned against the semiconductor body for receiving the light from the coupling elements.
48 citations
TL;DR: In this paper, the authors describe a fully-integrated evanescent opto-nanomechanical transducer based on a high-stress Si$_3$N$_4$ nanobeam monolithically suspended above a SiO$_2$ microdisk cavity.
Abstract: Placing a nanomechanical object in the evanescent near-field of a high-$Q$ optical microcavity gives access to strong gradient forces and quantum-noise-limited displacement readout, offering an attractive platform for precision sensing technology and basic quantum optics research. Robustly implementing this platform is challenging, however, as it requires separating optically smooth surfaces by $\lesssim\lambda/10$. Here we describe a fully-integrated evanescent opto-nanomechanical transducer based on a high-stress Si$_3$N$_4$ nanobeam monolithically suspended above a SiO$_2$ microdisk cavity. Employing a novel vertical integration technique based on planarized sacrificial layers, we achieve beam-disk gaps as little as 25 nm while maintaining mechanical $Q\times f>10^{12}$ Hz and intrinsic optical $Q\sim10^7$. The combined low loss, small gap, and parallel-plane geometry result in exceptionally efficient transduction, characterizing by radio-frequency flexural modes with vacuum optomechanical coupling rates of 100 kHz, single-photon cooperativities in excess of unity, and zero-point frequency (displacement) noise amplitudes of 10 kHz (fm)/$\surd$Hz. In conjunction with the high power handling capacity of SiO$_2$ and low extraneous substrate noise, the transducer operates particularly well as a sensor. Deploying it in a 4 K cryostat, we recently demonstrated a displacement imprecision 40 dB below that at the standard quantum limit (SQL) with an imprecision-back-action product $<5\cdot\hbar$. In this report we provide a comprehensive description of device design, fabrication, and characterization, with an emphasis on extending Heisenberg-limited readout to room temperature. Towards this end, we describe a room temperature experiment in which a displacement imprecision 30 dB below that at the SQL and an imprecision-back-action product $<75\cdot\hbar$ is achieved.
40 citations
TL;DR: With a nearly polarization degenerate microcavity in the weak coupling regime, polarization pre- and postselection can be used to restore high fidelity and transform incident coherent light into a stream of strongly correlated photons with a second-order correlation value up to 40, larger than previous experimental results, even in the strong-coupling regime.
Abstract: Single photon nonlinearities based on a semiconductor quantum dot in an optical microcavity are a promising candidate for integrated optical quantum information processing nodes. In practice, however, the finite quantum dot lifetime and cavity-quantum dot coupling lead to reduced fidelity. Here we show that, with a nearly polarization degenerate microcavity in the weak coupling regime, polarization pre- and postselection can be used to restore high fidelity. The two orthogonally polarized transmission amplitudes interfere at the output polarizer; for special polarization angles, which depend only on the device cooperativity, this enables cancellation of light that did not interact with the quantum dot. With this, we can transform incident coherent light into a stream of strongly correlated photons with a second-order correlation value up to 40, larger than previous experimental results, even in the strong-coupling regime. This purification technique might also be useful to improve the fidelity of quantum dot based logic gates.
TL;DR: In this paper, the authors proposed a spin-cavity transistor based on the giant circular birefringence induced by a single spin in a double-sided optical microcave.
Abstract: The realization of quantum computers and quantum Internet requires not only quantum gates and quantum memories, but also transistors at single-photon levels to control the flow of information encoded on single photons. Single-photon transistor (SPT) is an optical transistor in the quantum limit, which uses a single photon to open or block a photonic channel. In sharp contrast to all previous SPT proposals which are based on single-photon nonlinearities, here I present a design for a high-gain and high-speed (up to THz) SPT based on a linear optical effect: giant circular birefringence induced by a single spin in a double-sided optical microcavity. A gate photon sets the spin state via projective measurement and controls the light propagation in the optical channel. This spin-cavity transistor can be directly configured as diodes, routers, DRAM units, switches, modulators, etc. Due to the duality as quantum gate and transistor, the spin-cavity unit provides a solid-state platform ideal for future Internet: a mixture of all-optical Internet with quantum Internet.
TL;DR: In this article, a properly tuned silicon on insulator microcavity was used to trap and identify three different kinds of bacteria through the spatial and temporal observations of bacteria interaction.
Abstract: Photonic crystals and microcavities act as on-chip nano-optical tweezers for identification and manipulation of biological objects. Until now, optical trapping of virus and bacteria has been achieved and their presence in the vicinity of the optical resonator is deduced by the shift in the resonant wavelength. Here, we show trapping and identification of bacteria through a properly tuned silicon on insulator microcavity. Through the spatial and temporal observations of bacteria–cavity interaction, the optical identification of three different kinds of bacteria is demonstrated.
TL;DR: In this paper, a rolled-up thin-walled oxide tubular microcavity delivers a new optical component for light coupling and may imply interesting applications in the interaction between light and matter.
Abstract: Nanomembrane self-rolling offers the manufacture flexibility of 3D architectures for various applications in photonics, robotics, electronics, etc. Rolled-up oxide microtubes fabricated by both wet chemical etching and dry-releasing methods enable a broad range tuning of diameters (from 1 to 15 μm) and therefore same to their optical whispering gallery modes (WGMs). Their thin walls (several tens of nanometers) of such tubular optical microcavities provide strongly on-resonance coupling of attached dye emitters to optical modes, which leads to a cavity enhancement for Raman scattering without importing noble metal. Rolled-up thin-walled oxide tubular microcavity delivers a new optical component for light coupling and may imply interesting applications in the interaction between light and matter.
TL;DR: In this article, a crystalline whispering gallery mode microcavity was fabricated by using a computer-controlled ultraprecision cutting process to control the cavity cross-section.
Abstract: We fabricated a crystalline whispering gallery mode microcavity by using a computer-controlled ultraprecision cutting process to control the cavity cross section. We used a numerical simulation to show that a wide-spanning optical Kerr frequency comb is generated by tailoring the dispersion of a crystalline whispering gallery mode microcavity. To control the dispersion, we designed the cross-sectional shape of the device and fabricated it by using ultraprecision cutting. Both the measured value and the numerical result show that the microcavity has an anomalous dispersion over one octave.
TL;DR: In this article, the authors proposed a mode coupling between a square microcavity and a Fabry-Perot (FP) cavity for realizing single mode lasers and demonstrated tunable single mode operation with a continuous wavelength tuning range over 10nm.
Abstract: Mode coupling between a square microcavity and a Fabry-Perot (FP) cavity is proposed and demonstrated for realizing single mode lasers. The modulations of the mode Q factor as simulation results are observed and single mode operation is obtained with a side mode suppression ratio of 46 dB and a single mode fiber coupling loss of 3.2 dB for an AlGaInAs/InP hybrid laser as a 300-μm-length and 1.5-μm-wide FP cavity connected to a vertex of a 10-μm-side square microcavity. Furthermore, tunable single mode operation is demonstrated with a continuous wavelength tuning range over 10 nm. The simple hybrid structure may shed light on practical applications of whispering-gallery mode microcavities in large-scale photonic integrated circuits and optical communication and interconnection.
TL;DR: An experimental investigation on the spectra of fully chaotic and nonchaotic microcavity lasers under continuous-wave operating conditions finds that fully chaotic microc Cavity lasers operate in single mode, whereas nonchaotics operate in multimode.
Abstract: We report an experimental investigation on the spectra of fully chaotic and nonchaotic microcavity lasers under continuous-wave operating conditions. It is found that fully chaotic microcavity lasers operate in single mode, whereas nonchaotic microcavity lasers operate in multimode. The suppression of multimode lasing for fully chaotic microcavity lasers is explained by large spatial overlaps of the resonance wave functions that spread throughout the two-dimensional cavity due to the ergodicity of chaotic ray orbits.
TL;DR: In this paper, a silicon nanophotonic chip capable of emitting telecommunication band photon pairs that exhibit the highest raw degree of time-energy entanglement from a micro/nanoscale source is presented.
Abstract: Advances in quantum photonics have shown that chip-scale quantum devices are translating from the realm of basic research to applied technologies. Recent developments in integrated photonic circuits and single photon detectors indicate that the bottleneck for fidelity in quantum photonic processes will ultimately lie with the photon sources. We present and demonstrate a silicon nanophotonic chip capable of emitting telecommunication band photon pairs that exhibit the highest raw degree of time-energy entanglement from a micro/nanoscale source, to date. Biphotons are generated through cavity-enhanced spontaneous four-wave mixing (SFWM) in a high-Q silicon microdisk resonator, wherein the nature of the triply resonant generation process leads to a dramatic Purcell enhancement, resulting in highly efficient pair creation rates as well as extreme suppression of the photon noise background. The combination of the excellent photon source and a new phase locking technique allow for the observation of a nearly pe...
TL;DR: In this article, the authors theoretically investigate the generation of atom-light entanglement via Raman superradiance in an optical cavity, and show how this can be used to enhance the sensitivity of atom interferometry.
Abstract: We theoretically investigate the generation of atom-light entanglement via Raman superradiance in an optical cavity, and show how this can be used to enhance the sensitivity of atom interferometry. We model a realistic optical cavity, and show that by careful temporal shaping of the optical local oscillator used to measure the light emitted from the cavity, information in the optical mode can be combined with the signal from the atom interferometer to reduce the quantum noise, and thus increase the sensitivity. It was found in Phys. Rev. Lett. 110, 053002 (2013) that an atomic “seed” was required in order to reduce spontaneous emission and allow for single mode behavior of the device. In this paper we find that the optical cavity reduces the need for an atomic seed, which allows for stronger atom-light correlations and a greater level of quantum enhancement.
TL;DR: In this paper, a colloidal quantum dot gain medium with a threshold of 20 mJ/cm2 was used for single-mode lasing operation using nanosecond optical excitation.
Abstract: We monolithically fabricated vertical cavity lasers with densely packed colloidal quantum dot films and demonstrated single-mode lasing operation using nanosecond optical excitation. Due to the accurate spectral and spatial alignment of the cavity optical modes and the quantum dot gains, in addition to the high quality factors of our devices, we observed lasing from a colloidal quantum dot gain medium only 35 nm thick (6 or 7 monolayers thick) with a threshold of 20 mJ/cm2. We fabricated a laser with more numerous quantum dot layers as well, which exhibited a lower lasing threshold of 9 mJ/cm2 due to the enhanced modal gain. This work represents an important step toward fabricating monolithic colloidal quantum dot lasers for practical photonic devices.
TL;DR: The present elongated hexagonal microcavity exhibited quite different features for its optical resonant modes due to the broken hexagonal symmetry, and the resonant mode evolution was investigated systemically by using a spatially resolved spectroscopic technique.
Abstract: We have developed a novel but simple approach to obtain ZnO microcombs with parallelogram stems and elongated hexagonal branches. We found that the present elongated hexagonal microcavity exhibited quite different features for its optical resonant modes due to the broken hexagonal symmetry. The resonant mode evolution of such microcavity was investigated systemically by using a spatially resolved spectroscopic technique. Theoretical analyses based on the plane wave mode and FEM simulations agreed well with the experimental results. We believe that our research allows us to have a deeper understanding of the controllable growth of novel optical cavities and the shape-dependent optical resonant modes.
TL;DR: In this paper, an optical microcavity formed between a metallic layer coated on the back of the cantilever and one coated at the end of an optical fiber was used to circumvent this problem.
Abstract: Bimaterial cantilevers have recently been used in, for example, the calorimetric analysis with picowatt resolution in microscopic space based on state-of-the-art atomic force microscopes. However, thermally induced effects usually change physical properties of the cantilevers, such as the resonance frequency, which reduce the accuracy of the measurements. Here, we propose an approach to circumvent this problem that uses an optical microcavity formed between a metallic layer coated on the back of the cantilever and one coated at the end of an optical fiber irradiating the cantilever. In addition to increasing the sensitivity, the optical rigidity of this system diminishes the thermally induced frequency shift. For a coating thickness of several tens of nanometers, the input power is 5–10 μW. These values can be evaluated from parameters derived by directly irradiating the cantilever in the absence of the microcavity. The system has the potential of using the cantilever both as a thermometer without frequency shifting and as a sensor with nanometer-controlled accuracy.
TL;DR: In this article, the authors studied the nonperturbative spontaneous emission of collective excitations in a dense two-dimensional electron gas that superradiantly decays into free space.
Abstract: Strong and ultrastrong light-matter coupling are remarkable phenomena of quantum electrodynamics occurring when the interaction between matter excitation and an electromagnetic field cannot be described by usual perturbation theory. This is generally achieved by coupling an excitation with large oscillator strength to the confined electromagnetic mode of an optical microcavity. In this work, we demonstrate that strong/ultrastrong coupling can also take place in the absence of optical confinement. We have studied the nonperturbative spontaneous emission of collective excitations in a dense two-dimensional electron gas that superradiantly decays into free space. By using a quantum model based on the input-output formalism, we have derived the linear optical properties of the coupled system, and we demonstrated that its eigenstates are mixed light-matter particles, as in any system displaying strong or ultrastrong light-matter interaction. Moreover, we have shown that in the ultrastrong coupling regime, i.e., when the radiative broadening is comparable to the matter excitation energy, the commonly used rotating-wave and Markov approximations yield unphysical results. Finally, the input-output formalism has allowed us to prove that Kirchhoff's law, describing thermal emission properties, applies to our system in all the light-matter coupling regimes considered in this work.
TL;DR: In this paper, the theory of resonant absorption by Mie modes in a single high-index sphere is reviewed and engineering rules established, and silicon colloids are presented as efficient absorbers in the VIS-NIR region.
Abstract: Silicon colloids are presented as efficient absorbers in the VIS-NIR region. The theory of resonant absorption by Mie modes in a single high-index sphere is reviewed and engineering rules established. The presented model predicts enhanced absorption in the crystalline silicon band-to-band absorption region, with absorption efficiencies exceeding one in the VIS and excellent NIR response. A maximum resonant absorption efficiency close to 4 can be obtained at the violet region (425 nm), and values above 0.25 are possible in the bandgap edge at wavelengths up to 1400 nm. Silicon colloids are proposed as a promising cost-effective, silicon saving, sunlight harvesters with improved VIS and NIR response.
TL;DR: A vertical microcavity based on distributed Bragg reflector and Ag source/drain electrodes is successfully introduced into the high performance OLEFETs, which results in electroluminescent spectrum linewidth narrowing from 96’nm to 6.9 nm.
Abstract: Organic light-emitting field-effect transistors (OLEFETs) are regarded as a novel kind of device architecture for fulfilling electrical-pumped organic lasers. However, the realization of OLEFETs with high external quantum efficiency (EQE) and high brightness simultaneously is still a tough task. Moreover, the design of the resonator structure in LED is far from satisfactory. Here, OLEFETs with EQE of 1.5% at the brightness of 2600 cdm(-2), and the corresponding ON/OFF ratio and current efficiency reaches above 10(4) and 3.1 cdA(-1), respectively, were achieved by introducing 1,4,5,8,9,12-hexaazatriphenylene-hexacarbonitrile (HAT-CN) as a charge generation layer. Moreover, a vertical microcavity based on distributed Bragg reflector (DBR) and Ag source/drain electrodes is successfully introduced into the high performance OLEFETs, which results in electroluminescent spectrum linewidth narrowing from 96 nm to 6.9 nm. The results manifest the superiority of the vertical microcavity as an optical resonator in OLEFETs, which sheds some light on achieving the electrically pumped organic lasers.
TL;DR: In this article, the authors demonstrate a method to measure the thermal relaxation time and effective thermal conductance of a whispering gallery mode microcavity using optothermal effect, which can be applied to various resonators in different forms.
Abstract: Thermal properties of a photonic resonator are determined not only by intrinsic properties of materials, such as thermo-optic coefficient, but also by the geometry and structure of the resonator. Techniques for characterization and measurement of thermal properties of individual photonic resonator will benefit numerous applications. In this work, we demonstrate a method to optically measure the thermal relaxation time and effective thermal conductance of a whispering gallery mode microcavity using optothermal effect. Two nearby optical modes within the cavity are optically probed, which allows us to quantify the thermal relaxation process of the cavity by analyzing changes in the transmission spectra induced by optothermal effect. We show that the effective thermal conductance can be experimentally deduced from the thermal relaxation measurement, and it can be tailored by changing the geometric parameters of the cavity. The experimental observations are in good agreement with the proposed analytical modeling. This method can be applied to various resonators in different forms.
TL;DR: In this paper, concentric circular Bragg gratings intimately incorporating CdSe/CdZnS/Zns gradient shell CQDs are used for CQD-based single mode lasing.
Abstract: Since optical gain was observed from colloidal quantum dots (CQDs), research on CQD lasing has been focused on the CQDs themselves as gain materials and their coupling with optical resonators. Combining the advantages of a CQD gain medium and optical microcavity in a laser device is desirable. Here, we show concentric circular Bragg gratings intimately incorporating CdSe/CdZnS/ZnS gradient shell CQDs. Because of the strong circularly symmetric optical confinement in two dimensions, the output beam CQD-based circular grating distributed feedback laser is found to be highly spatially coherent and azimuthally polarized with a donut-like cross section. We also observe the strong modification of the photoluminescence spectrum by the grating structures, which is associated with modification of optical density of states. This effect confirmed the high quality of the resonator that we fabricated and the spectral overlap between the optical transitions of the emitter and resonance of the cavity. Single mode lasing...
TL;DR: In this paper, anisotropic exciton-photon coupling has been observed in a highly oriented organic single crystal microcavity, which consists of a thiophene/phenylene co-oligomer (TPCO) single crystal laminated on a high-reflection distributed Bragg reflector.
Abstract: Strong exciton-photon coupling has been observed in a highly oriented organic single crystal microcavity. This microcavity consists of a thiophene/phenylene co-oligomer (TPCO) single crystal laminated on a high-reflection distributed Bragg reflector. In the TPCO crystal, molecular transition dipole was strongly polarized along a certain horizontal directions with respect to the main crystal plane. This dipole polarization causes significantly large anisotropies in the exciton transition and optical constants. Especially the anisotropic exciton transition was found to provide the strong enhancement in the coupling with the cavity mode, which was demonstrated by a Rabi splitting energy as large as ∼100 meV even in the “half-vertical cavity surface emitting lasing” microcavity structure.
TL;DR: An overview of the different possible sensing modalities is provided, with examples of refractive index sensing, optical absorption measurements, and optical tracking and trapping of nanoparticles.
Abstract: The recent development of open-access optical microcavities opens up a number of intriguing possibilities in the realm of chemical sensing. We provide an overview of the different possible sensing modalities, with examples of refractive index sensing, optical absorption measurements, and optical tracking and trapping of nanoparticles. The extremely small mode volumes within an optical microcavity allow very small numbers of molecules to be probed: our current best detection limits for refractive index and absorption sensing are around 10(5) and 10(2) molecules, respectively, with scope for further improvements in the future.
TL;DR: By considering driven diffusive dynamics of exciton polaritons in an optical microcavity with an embedded molybdenum disulfide (MoS2) monolayer, the authors determined an experimentally relevant range of parameters at which room-temperature superfluidity can be observed.
Abstract: By considering driven diffusive dynamics of exciton polaritons in an optical microcavity with an embedded molybdenum disulfide (MoS2) monolayer, we determine an experimentally relevant range of parameters at which room-temperature superfluidity can be observed. It is shown that the superfluid transitions occur in a trapped polariton gas at a laser pumping power of P>600 mW and a trapping potential strength of k>50 eV/cm2. We also propose a simple analytic model that provides a useful estimate for the polariton gas density, which enables one to determine the conditions for the observation of room-temperature polariton superfluidity.