Light pressure effect has been discovered long ago and has been used as an optical method to manipulate microand nanoparticles. It is usually considered as a nonresonant effect determined by the transfer of the momentum of light. However, recently we have observed that large polystyrene microspheres of 15-20 μm diameters supporting high quality whispering gallery resonances can be optically propelled in water at an extraordinary high velocity along tapered fibers under resonant conditions. In this work we compare on- and off-resonant optical forces in microspherical photonics by controlling the detuning between the laser emission line and whispering gallery resonances. Our approach involves manipulation with microspheres using conventional optical tweezers and their advanced spectroscopic characterization in fiber-integrated setups. We demonstrate dramatic difference in the optical forces exerted on microspheres in the on-resonant and off-resonant cases. This method can be used to study spectral properties of the resonantly enhanced forces in microspherical photonics.
Dielectric microspheres with diameters on the order of several wavelengths of light have attracted increasing attention from the photonics community due to their ability to produce extraordinarily tightly focused beams termed photonic nanojets, to be used as microlenses for achieving optical super-resolution or to develop sensors based on whispering-gallery mode resonances. In this dissertation, we study the optical properties of more complicated structures formed by multiple spheres which can be assembled as linear chains, clusters or arrays, integrated with waveguides or embedded inside othe…
In this dissertation novel resonant propulsion of dielectric microspheres is studied with the goal of sorting spheres with identical resonances, which are critical for developing microspherical photonics. First, evanescent field couplers were developed by fixing tapered microfibers in mechanically robust platforms. The tapers were obtained by chemical etching techniques. Using these platforms, WGMs modal numbers, coupling regimes and quality factors were determined for various spheres and compared with theory. Second, the spectroscopic properties of photonic molecules formed by spheres with be…
Energy-efficient optical control of photonic device properties is crucial for diverse photonic signal processing. Here we demonstrate extremely efficient optical tuning of photonic nanocavities, with only photon-level optical energy. With a lithium niobate photonic crystal nanocavity with an optical Q up to 1.41 million and an effective mode volume down to 0.78$(λ/n)^3$, we are able to achieve a resonance tuning rate of about 88.4~MHz/photon (0.67~GHz/aJ), which allows us to tune across the whole cavity resonance with only about 2.4 photons on average inside the cavity. Such a photon-level res…
Near the band edge of photonic crystal waveguides, localized modes appear due to disorder. We demonstrate a new method to elucidate spatial profile of the localized modes in such systems using precise local tuning. Using deconvolution with the known thermal profile, the spatial profile of a localized mode with quality factor ($Q$) $>10^5$ is successfully reconstructed with a resolution of $2.5 \ μ$m.
The active tuning of the structural colour in photonic crystals by an electric field represents an effective external stimulus with impact on light transmission manipulation. In this work we present this effect in a photonic crystal device with alternating layers of Silver and Titanium dioxide nanoparticles showing shifts of around 10 nm for an applied voltage of 10 V only. The accumulation of charges at the metal/dielectric interface with applied electric field leads to an effective increase of the charges contributing to the plasma frequency in Silver. This initiates a blue shift of the Silv…
Interface states in photonic crystals usually require defects or surface/interface decorations. We show here that one can control interface states in 1D photonic crystals through the engineering of geometrical phase such that interface states can be guaranteed in even or odd, or in all photonic bandgaps. We verify experimentally the designed interface states in 1D multilayered photonic crystals fabricated by electron beam vapor deposition. We also obtain the geometrical phases by measuring the reflection phases at the bandgaps of the PCs and achieve good agreement with the theory. Our approach…
From fundamental discovery to practical application, advances in the optical and quantum sciences rely upon precise control of light-matter interactions. Systems of coupled optical cavities are ubiquitous in these efforts, yet design and active modification of the hybridized mode properties remains challenging. In this Letter, we demonstrate the ability to thermally control the degree of hybridization in a heterogeneous photonic molecule composed of a ring resonator strongly coupled to a nanobeam photonic crystal cavity. Combining theory and experiment, we show that the composition of the resu…
We present a detailed numerical investigation of the tunability of a diffusive random laser when Mie resonances are excited. We solve a multimode diffusion model and calculate multiple light scattering in presence of optical gain which includes dispersion in both scattering and gain, without any assumptions about the $β$ parameter. This allows us to investigate a realistic photonic glass made of latex spheres and rhodamine and to quantify both the lasing wavelength tunability range and the lasing threshold. Beyond what is expected by diffusive monochromatic models, the highest threshold is fou…
Canonical Four-Wave-Mixing occurs in a resonator with only the required number of modes, thereby inhibiting competing parametric processes. The properties of the recently introduced photonic crystal parametric oscillator, Marty et al. Nat. Photonics, 15, 53 (2021), are discussed extensively. We compare the bichromatic design with other geometries of photonic crystal resonators. Based on a statistical study over more than 100 resonators and 10 parametric oscillators, robustness against fabrication tolerances is assessed, performances are evaluated in terms of average values and their dispersion…
Thermally-tuning silicon micro-cavities are versatile and beneficial elements in low-cost large-scale photonic integrated circuits (PICs). Traditional metal heaters used for thermal tuning in silicon micro-cavities usually need a thick SiO2 upper-cladding layer, which will introduce some disadvantages including low response speed, low heating efficiency, low achievable temperature and complicated fabrication processes. In this paper, we propose and experimentally demonstrate thermally-tuning silicon micro-disk resonators by introducing graphene transparent nano-heaters, which contacts the sili…
The employment of magneto-optical materials to fabricate photonic crystals gives the unique opportunity to achieve optical tuning by applying a magnetic field. In this study we have simulated the transmission spectrum of a microcavity in which the Bragg reflectors are made with silica (SiO2) and yttria (Y2O3) and the defect layer is made with TGG (Tb3Ga5O12). We show that the application of an external magnetic field results in a tuning of the defect mode of the microcavity. In the simulations we have considered the wavelength dependence of the refractive indexes and the Verdet constants of th…
Crystal-symmetry-protected photonic topological edge states (PTESs) based on air rods in conventional dielectric materials are designed as photonic topological waveguides (PTWs) coupled with side optical cavities. We demonstrate that the cavity coupled with the PTW can change the reflection-free transport of the PTESs, where the cavities with single mode and twofold degenerate modes are taken as examples. The single-mode cavities are able to perfectly reflect the PTESs at their resonant frequencies, forming a dip in the transmission spectra. The dip full width at half depth depends on the coup…
Although complex, hierarchical nanoscale geometries with tailored degrees of disorder are commonly found in biological systems, few simple self-assembly routes to fabricating synthetic analogues have been identified. We present two techniques that exploit basic capillary phenomena to finely control disorder in porous 3D photonic crystals, leading to complex and hierarchical geometries. In the first, we exposed the structures to mixtures of ethanol and water that partially wet their pores, where small adjustments to the ethanol content controlled the degree of partial wetting. In the second, we…
Tunable optical material properties enable novel applications in both versatile metamaterials and photonic components including optical sources and modulators. Transparent conductive oxides (TCOs) are able to highly tune their optical properties with applied bias via altering their free carrier concentration and hence plasma dispersion. The TCO material indium tin oxide (ITO) exhibits unity-strong index changes, and epsilon-near-zero behavior. However, with such tuning the corresponding high optical losses, originating from the fundamental Kramers-Kronig relations, result in low cavity finesse…
Surface modes (SM) are highly spatially localized modes existing at the core-cladding interface of photonic-bandgap hollow-core fiber (PBG-HCF). When coupling with SM, the air modes (AM) in the core would suffer a higher loss despite being spectrally within the cladding photonic bandgap, and would be highly dispersive around the avoided crossing (anti-crossing) wavelength. In this paper, we numerically demonstrate that such avoided crossings can play an important role in the tuning of the temperature dependence of group delay of AM of PBG-HCF. At higher temperatures, both the thermal-optic eff…
Drift-free characterization of electro-optic tuning efficiency in lithium niobate photonic nanocavities
State Key Laboratory of Wide-Bandgap Semiconductor Devices and Integrated Technology, Faculty of Integrated Circuits, Xidian University（西安电子科技大学集成电路学院宽禁带半导体器件与集成技术国家重点实验室）
We demonstrate that symmetry breaking opens a new degree of freedom to tailor the energy-momentum dispersion in photonic crystals. Using a general theoretical framework in two illustrative practical structures, we show that breaking symmetry enables an on-demand tuning of the local density of states of a same photonic band from zero (Dirac cone dispersion) to infinity (flatband dispersion), as well as any constant density over an adjustable spectral range. As a proof-of-concept, we experimentally demonstrate the transformation of a very same photonic band from conventional quadratic shape to D…
Highly selective and reconfigurable microwave filters are of great importance in radio-frequency signal processing. Microwave photonic (MWP) filters are of particular interest, as they offer flexible reconfiguration and an order of magnitude higher frequency tuning range than electronic filters. However, all MWP filters to date have been limited by trade-offs between key parameters such as tuning range, resolution, and suppression. This problem is exacerbated in the case of integrated MWP filters, blocking the path to compact, high performance filters. Here we show the first chip-based MWP ban…
Chalcogenide glass (ChG) is an attractive material for integrated nonlinear photonics due to its wide transparency and high nonlinearity, and its capability of being directly deposited and patterned on Silicon wafer substrates. It has a singular Raman effect among amorphous materials. Yet, the Raman lasing performance in high quality and chip integrated ChG microresonators remains unexplored. Here, we demonstrate an engineered Raman lasing dynamic based on home developed photonic integrated high-Q ChG microresonators. With a quality factor above 10^6, we achieve the record-low lasing threshold…
Photonic molecules can be used to realize complex optical energy states and modes, analogous to those found in molecules, with properties useful for applications like spectral engineering and quantum optics. It is desirable to implement photonic molecules using high quality factor photonic integrated ring resonators due to their narrow atom-like spectral resonance, tunability, and the ability to scale the number of resonators on a photonic circuit. However, to take full advantage of molecule spectral complexity and tuning degree of freedom, resonator structures should have full symmetry in ter…
A new tuning mechanism is introduced in high-Q multimode photonic crystal resonators allowing to harness the resonant enhancement of the parametric resonance systematically. As a consequence, ultra-efficient stimulated and spontaneous Four Wave Mixing at continuous microWatt pumping levels are observed, and the scaling with Q is demonstrated. Experimental results are in perfect agreement with an analytical model without fitting parameters.
Slow light has been widely utilized to obtain enhanced nonlinearities, enhanced spontaneous emissions, and increased phase shifts owing to its ability to promote light-matter interactions. By incorporating a graphene microheater on a slow-light silicon photonic crystal waveguide, we experimentally demonstrated an energy-efficient graphene microheater with a tuning efficiency of 1.07 nm/mW and power consumption per free spectral range of 3.99 mW. The rise and decay times (10% to 90%) were only 750 ns and 525 ns, which, to the best of our knowledge, are the fastest reported response times for mi…
Mechanical tuning of a 3D-printed, polymer-based one-dimensional photonic crystal was demonstrated in the terahertz spectral range. The investigated photonic crystal consists of 13 alternating compact and low-density layers and was fabricated through single-step stereolithography. While the compact layers are entirely polymethacrylate without any intentional internal structures, the low-density layers contain sub-wavelength sized slanted columnar inclusions to allow the mechanical compression in a direction normal to the layer interfaces of the photonic crystal. Terahertz transmission spectros…
Phase-locking of large mode area Yb photonic crystal fiber amplifiers via stimulated Brillouin scattering phase conjugation is analyzed. The wavefront reversing mirrors are proposed for chirped pulse fiber laser networks. The chirp control via both nonresonant Kerr and resonant index is considered.
The MITRE Corporation（MITRE公司）；Sandia National Laboratories（桑迪亚国家实验室）；College of Optical Sciences, University of Arizona（亚利桑那大学光学科学学院）；Electrical, Computer, and Energy Engineering, University of Colorado Boulder（科罗拉多大学博尔德分校电气、计算机和能源工程学院）
We investigate the effect of tunable optical feedback on a commercial DFB laser edge coupled to a Silicon Photonics planar integrated circuit in which a tunable reflector has been implemented by means of a ring resonator based add-drop multiplexer. Controlled optical feedback allows for fine-tuning of the laser oscillation frequency. Under certain conditions it also allows suppression of bifurcation modes triggered by reflections occurring elsewhere on the chip. A semi-analytical model describing laser dynamics under combined optical feedback from the input facet of the edge coupler and from t…
