The dynamics of two-dimensional electromagnetic (EM) pulses through one-dimensional photonic crystals (1DPC) has been theoretically studied. Employing the time expectation integral over the Poynting vector as the arrival time [Phys. Rev. Lett. 84, 2370, (2000)], we show that the superluminal tunneling process of EM pulses is the propagation of the net forward-going Poynting vector through the 1DPC, and the Hartman effect is due to the saturation effect of the arrival time (smaller and smaller time accumulated) of the net forward energy flow caused by the interference effect of the forward and the backward field (from the interfaces of each layer) happened in the region before the 1DPC and in the front part of the 1DPC.
Squeezed light has evolved into a powerful tool for quantum technology, ranging from quantum enhanced sensing and quantum state engineering based on partial post-selection techniques. The pulsed generation of squeezed light is of particular interest, as it can provide accurate time stamp and physically defined temporal mode, which are highly preferred in complex communication networks and large-scale information processing. However, the multimode feature of pulsed squeezing in conventional single-pass configuration limits the purity of the output state, negatively impacting its application in …
We present a comprehensive theoretical analysis and computational study of four-wave mixing (FWM) of optical pulses co-propagating in one-dimensional silicon photonic crystal waveguides (Si-PhCWGs). Our theoretical analysis describes a very general set-up of the interacting optical pulses, namely we consider nondegenerate FWM in a configuration in which at each frequency there exists a superposition of guiding modes. We incorporate in our theoretical model all relevant linear optical effects, including waveguide loss, free-carrier (FC) dispersion and FC absorption, nonlinear optical effects su…
We propose and experimentally demonstrate femtosecond direct laser writing with Bessel beams for the fabrication of photonic crystals with spatial filtering functionality. Such filters are mechanically stable, of small (of order of millimeter) size, do not require direct access to the far-field domain, and therefore are excellent candidates for intracavity spatial filtering applications in mini- and micro-lasers. The technique allows the fabrication of efficient photonic crystal spatial filters in glass, with a narrow angle (~1 degree) nearly 100%-transmission pass-band between broad angle (up…
We report on the higher-order photon correlations of a high-$β$ nanolaser under pulsed excitation at room temperature. Using a multiplexed four-element superconducting single photon detector we measured g$^{(n)}(\vec{0})$ with $n$=2,3,4. All orders of correlation display partially chaotic statistics, even at four times the threshold excitation power. We show that this departure from coherence and Poisson statistics is due to the quantum fluctuations associated with the small number of dipoles and photons involved in the lasing process.
The density of Bloch electromagnetic states inside a one dimensional photonic crystal (1D PC) is formulated based on its dispersion relations. The formulation applied to any anisotropic medium with known dispersion relations and iso-frequency surfaces. Using a practical 1D PC parameters in the visible range, the density of Bloch states for different modes are calculated.
We report direct observation of the development of long-range spatial intensity correlations and the growth of intensity fluctuations inside the random media. We fabricated quasi-two-dimensional disordered photonic structures and probed the light transport from a third dimension. Good agreements between experiment and theory are obtained. We were able to manipulate the long-range intensity correlations and intensity fluctuations inside the disordered waveguides by simply varying the waveguide geometry.
In this article, we present a numerical study of the optical properties of a metal nanowire interacting with a localized cavity in a two dimensional photonic crystal. The nature of the modes, their wavelength and width are investigated as a function of the particle radius. It is shown in particular that a particle with diameter about the lattice constant presents very narrow resonances corresponding to hybrid photonic-plasmonic modes, where increased lifetime is attributed to the decrease of the radiative losses by interaction with the photonic crystal. These results open interesting applicati…
We theoretically study the effect of pulse trapping inside one-dimensional photonic crystal with relaxing cubic nonlinearity. We analyze dependence of light localization on pulse intensity and explain its physical mechanism as connected with formation of dynamical nonlinear cavity inside the structure. We search for the range of optimal values of parameters (relaxation time and pulse duration) and show that pulse trapping can be observed only for positive nonlinearity coefficients. We suppose that this effect can be useful for realization of optical memory and limiting.
Different densities of electromagnetic states inside a one dimensional photonic crystal (1D PC) are studied. Hertz vector formalism is used to calculate Green tensor inside a layered structure, semi-analytically. Based on the obtained Green tensor, the local density of electromagnetic states (LDOS) and the density of states (DOS) inside a 1D PC are calculated and discussed. The Green tensor is also used to approximate the density of Bloch states inside the 1D PC and is compared with its exact calculation based on the 1D PC dispersion relations. Using a practical 1D PC parameters in the visible…
We present a method to map the absolute electromagnetic field strength inside photonic crystals. We apply the method to map the electric field component Ez of a two-dimensional photonic crystal slab at microwave frequencies. The slab is placed between two mirrors to select Bloch standing waves and a subwavelength spherical scatterer is scanned inside the resulting resonator. The resonant Bloch frequencies shift depending on the electric field at the position of the scatterer. To map the electric field component Ez we measure the frequency shift in the reflection and transmission spectrum of th…
A polymer/liquid crystal-based fiber Bragg grating (PLC-FBG) is fabricated with visible two-beam holography by photo-induced modulation of a pre-polymer/LC solution infiltrated into the hollow channels of a solid core photonic crystal fiber (PCF). The fabrication process and effects related to the photonic bandgap guidance into the infiltrated PCF, and characterization of the PLC-FBG are discussed. Experimental data here presented, demonstrate that the liquid crystal inclusions of the PLC-FBG lead to high thermal and bending sensitivities. The microscopic behavior of the polymer/liquid crystal…
Silicon is an excellent material for microelectronics and integrated photonics with untapped potential for mid-IR optics. Despite broad recognition of the importance of the third dimension, current lithography methods do not allow fabrication of photonic devices and functional microelements directly inside silicon chips. Even relatively simple curved geometries cannot be realized with techniques like reactive ion etching. Embedded optical elements, like in glass, electronic devices and better electronic-photonic integration are lacking. Here, we demonstrate laser-based fabrication of complex 3…
A continuously tunable titanium:sapphire (Ti:Sa) laser self-seeded by an extended grating cavity was demonstrated and characterized. By inserting a partially reflecting mirror inside the cavity of a classic single-cavity grating laser, two oscillators are created: a broadband power oscillator, and a narrowband oscillator with a prism beam expander and a diffraction grating in Littrow configuration. By coupling the grating cavity oscillation into the power oscillator, a power-enhanced narrow-linewidth laser oscillation is achieved. Compared to the classic grating laser, this simple modification…
We demonstrate the dynamics of stimulated Raman scattering in designed high-Q/Vm silicon photonic band gap nanocavities through the coupled-mode theory framework towards optically-pumped silicon lasing. The interplay of other chi(3) effects such as two-photon absorption and optical Kerr, related free-carrier dynamics, thermal effects, as well as linear losses such as cavity radiation and linear material absorption are included and investigated numerically. Our results clarify the relative contributions and evolution of the mechanisms, and demonstrate the lasing and shutdown thresholds. Our stu…
We theoretically investigate the dispersion and polarization properties of the electromagnetic waves in a multi-layered structure composed of a magneto-optic waveguide on dielectric substrate covered by one-dimensional dielectric photonic crystal. The numerical analysis of such a complex structure shows polarization filtration of TE- and TM-modes depending on geometrical parameters of the waveguide and photonic crystal. We consider different regimes of the modes propagation inside such a structure: when guiding modes propagate inside the magnetic film and decay in the photonic crystal; when th…
At the exit surface of a photonic crystal, the intensity of the diffracted wave can be periodically modulated, showing a maximum in the "positive" (forward diffracted) or in the "negative" (diffracted) direction, depending on the slab thickness. This thickness dependence is a direct result of the so-called Pendellosung phenomenon, consisting of the periodic exchange inside the crystal of the energy between direct and diffracted beams. We report the experimental observation of this effect in the microwave region at about 14 GHz by irradiating 2D photonic crystal slabs of different thickness and…
We demonstrate an optical conveyor belt for levitated nano-particles over several centimeters inside both air-filled and evacuated hollow-core photonic crystal fibers (HCPCF). Detection of the transmitted light field allows three-dimensional read-out of the particle center-of-mass motion. An additional laser enables axial radiation pressure based feedback cooling over the full fiber length. We show that the particle dynamics is a sensitive local probe for characterizing the optical intensity profile inside the fiber as well as the pressure distribution along the fiber axis. In contrast to prev…
We propose an improved structure of an optical biosensor based on a photonic crystal (PC) with a defect layer (DL), which can detect the concentration of SARS-CoV-2 in water by defect mode (DM) shift. We investigated 4 types of defective PCs with different arrangements of layers inside the perfect PCs and their impact on the performance of the sensor. The sensitivity and amplitude of DM were examined as a function of DL thickness. Also, the peculiarities of edge modes in the presence of DL were investigated. Finally, we obtained a characteristic equation to determine the wavelengths of DMs for…
We present a numerical method for modelling noise in Stimulated Brillouin Scattering (SBS). The model applies to dynamic cases such as optical pulses, and accounts for both thermal noise and phase noise from the input lasers. Using this model, we compute the statistical properties of the optical and acoustic power in the pulsed spontaneous and stimulated Brillouin cases, and investigate the effects of gain and pulse width on noise levels. We find that thermal noise plays an important role in the statistical properties of the fields, and that laser phase noise impacts the SBS interaction when t…
We present a new type of compact and all-glass based vapour cell integrating hollow-core photonic crystal fibres. The absence of metals, as in a traditional vacuum chamber and the much more compact geometry allows for fast and homogeneous heating. As a consequence we can fill the fibres on much faster timescales, ranging from minutes to hours. Additionally the all-glass design ensures optical access along the fibre. This allows live monitoring of the diffusion of rubidium atoms inside the hollow-core by measuring the frequency-dependent fluorescence from the atoms. The atomic density is numeri…
We study the density of states (DOS) in band gaps of ideal and disordered three-dimensional photonic crystals of finite size. The ideal crystal is a diamond lattice of resonant point scatterers (atoms) whereas the disordered one is obtained from it by displacing the scatterers by random distances in random directions. We find that DOS inside a band gap of the ideal crystal decreases as the inverse of the crystal size. Disorder narrows the band gap and DOS exhibits enhanced fluctuations near the new band edges. However, the average DOS still exhibits the same scaling with the crystal size withi…
We report the radiation trapping effect inside a hollow-core photonic crystal fiber (PCF). An optical dipole trap was used to load and confine the atoms in the PCF without contacting the wall of the fiber. The transmission of a probe light propagating through the PCF was studied experimentally and theoretically. With the experimental results and theoretical predictions, we conclude that the radiation trapping can play a significant role and should be taken into account in the spectroscopic measurements inside the PCF.
The electronic chip industry embodies the height of technological sophistication and economics of scale. Fabricating inexpensive photonic components by leveraging this mighty manufacturing infrastructure has fueled intense interest in silicon photonics. If it can be done economically and in an energy efficient manner, empowering silicon with optical functionality will bring optical communications to the realm of computers where limitations of metallic interconnects are threatening the industry's future. The field is making stunning progress and stands to have a bright future, as long as the co…
We describe the loading of laser-cooled rubidium atoms into a single-mode hollow-core photonic-crystal fiber. Inside the fiber, the atoms are confined by a far-detuned optical trap and probed by a weak resonant beam. We describe different loading methods and compare their trade-offs in terms of implementation complexity and atom-loading efficiency. The most efficient procedure results in loading of ~30,000 rubidium atoms, which creates a medium with optical depth ~180 inside the fiber. Compared to our earlier study this represents a six-fold increase in maximum achieved optical depth in this s…
Two dimensional (2D) photonic crystals are well known for its ability to manipulate the propagation of electromagnetic wave inside the crystal. 1D and 2D photonic crystals are relatively easier to fabricate than 3D because the former work in the microwave and far infrared regions whereas the later work in the visible region and requires smaller lattice constants. In this paper, simulation for a modified 2D PC with two symmetric waveguide channels where a defect is located inside one of the channel is performed. The simulation results show that optical switching is possible by modifying the ref…
The temperature-dependent photoluminescence (PL) spectra of zinc oxide (ZnO) nanocrystals deposited inside the ultraviolet (UV) opal were studied. ZnO was grown in the voids between FCC packed silicon dioxide spheres using spray pyrolysis under ultrasonic vibration in the solution containing a zinc nitrate precursor. The ZnO nanoparticles inside opal matrix with UV photonic band-gap exhibit suppression of the excitonic emission and enhancement of the deep level emission. Suppression of the excitonic lines is due to the inhibition of spontaneous emission, while enhancement and broadening of the…
The idea of asymmetric light transmission through a photonic crystal with relaxing Kerr nonlinearity is presented. This idea is based on the symmetry breaking due to the self-trapping of intensive pump pulse inside the structure. As a result, the asymmetric transmission of the secondary (probe) pulses through the perturbed photonic crystal can be observed. The cases of short and long (quasi-continuous) probe pulses are considered.
In this study, we describe the formation of ZnO nanolayers inside the air capillaries of a silica photonic crystal fibre (PCF), targeting random laser and organic vapor sensing applications. ZnO nanolayers were developed by infiltrating the capillaries of the silica PCF with Zn-acetate/methanol solutions of various concentrations, followed by annealing treatments. The growth and morphology of the synthesized ZnO nanolayers were characterized by means of scanning electron microscopy (SEM) and found to be affected by the concentration of the Zn-acetate/methanol infiltration solution. For low con…
We propose an optical trapping technique in which a fundamental soliton traps an ultrashort small amplitude radiation in a symmetric hollow-core photonic crystal fiber filled with a noble gas, preventing its dispersion. The system is Raman- and plasma-free. Trapping is due to the cross phase modulation effect between the two pulses. The trapped radiation inside the soliton-induced potential will oscillate periodically due to the shock effect, similar to the motion of a mechanical pendulum.
We present an optical Kerr effect based time-gate with the collinear incidence of the pump and probe beams at the Kerr medium, liquid carbon disulfide, for ballistic imaging of the high-pressure fuel sprays. The probe pulse used to illuminate the object under study is extracted from the supercontinuum generated by tightly focusing intense femtosecond laser pulses inside water, thereby destroying their coherence. The optical imaging spatial resolution and gate timings are investigated and compared with a similar setup without supercontinuum generation, where the probe is still coherent. And fin…
We consider interaction of a femtosecond light pulse with a one-dimensional photonic crystal with relaxing cubic nonlinearity in the regime of self-trapping. By use of numerical simulations, it is shown that, under certain conditions, the spectra of reflected and transmitted light possess the properties of narrow-band (quasi-monochromatic) or wide-band (continuum-like) radiation. It is remarkable that these spectral features appear due to a significant frequency shift and occur inside a photonic band gap of the structure under investigation.
We propose an all-photonic, non-volatile memory and processing element based on phase-change thin-films deposited onto nanophotonic waveguides. Using photonic microring resonators partially covered with Ge2Sb2Te5 (GST) multi-level memory operation in integrated photonic circuits can be achieved. GST provides a dramatic change in refractive index upon transition from the amorphous to crystalline state, which is exploited to reversibly control both the extinction ratio and resonance wavelength of the microcavity with an additional gating port in analogy to optical transistors. Our analysis shows…
We investigate the impact of pulse interleaving and optical amplification on the spectral purity of microwave signals generated by photodetecting the pulsed output of an Er:fiber-based optical frequency comb. It is shown that the microwave phase noise floor can be extremely sensitive to delay length errors in the interleaver, and the contribution of the quantum noise from optical amplification to the phase noise can be reduced ~10 dB for short pulse detection. We exploit optical amplification, in conjunction with high power handling modified uni-traveling carrier photodetectors, to generate a …
It is well-known that electromagnetic radiation propagates along a straight line, but this common sense was broken by the artificial curved light - Airy beam. In this paper, we demonstrate a new type of curved light beam besides Airy beam, so called photonic hook. This photonic hook is a curved high-intensity focus by a dielectric trapezoid particle illuminated by a plane wave. The difference of the phase velocity and the interference of the waves inside the particle cause the phenomenon of focus bending.
Edge states of photonic crystals have attracted much attention for the potential applications such as high transmission waveguide bends, spin dependent splitters and one-way photonic circuits. Here, we theoretically discuss and experimentally observe the deterministic edge states in checkerboard photonic crystals. Due to the self-complementarity of checkerboard photonic crystals, a common band gap is structurally protected between two photonic crystals with different unit cells. Deterministic edge states are found inside the common band gap by exploiting the Zak phase analysis and surface impe…
Nano-fabrication in silicon, arguably the most important material for modern technology, has been limited exclusively to its surface. Existing lithographic methods cannot penetrate the wafer surface without altering it, whereas emerging laser-based subsurface or in-chip fabrication remains at > 1 micrometer resolution. In addition, available methods do not allow positioning or modulation with sub-micron precision deep inside the wafer. The fundamental difficulty of breaking these dimensional barriers are two-fold, i.e., complex nonlinear effects inside the wafer and the inherent diffraction li…
We investigate experimentally the light evolution inside a two-dimensional finite periodic array of weakly- coupled optical waveguides with a disordered boundary. For a completely localized initial condition away from the surface, we find that the disordered boundary induces an asymptotic localization in the bulk, centered around the initial position of the input beam.
We report on the first experimental observation of photonic Bloch oscillations and Zener tunneling in two-dimensional periodic systems. We study the propagation of an optical beam in a square photonic lattice superimposed on a refractive index ramp, and demonstrate the tunneling of light from the first to the higher-order transmission bands of the lattice bandgap spectrum, associated with the spectral dynamics inside the first Brillouin zone and corresponding oscillations of the primary beam.
We studied the optical properties of a dielectric photonic crystal structure with spirals arranged in a hexagonal lattice. The dielectric constant of the material is 9 and the filling ratio is 15.2%. We found that this kind of structure exhibits a significant polarization gap for light incident along the axis of the spirals. The eigenmodes inside the polarization gap are right-hand (left-hand) circularly polarized depending on the whether the spirals are left-handed (right-handed). The transmission spectrum of a slab of such a structure has been calculated and matches well with the analysis of…
We investigate nonlinear one- and two-dimensional photonic crystals by applying a finite element-iterative method.Numerical results show the essential influence of nonlinear elements embedded into a quarter-wave stack and the sharp photonic crystal waveguide bend on the spectral characteristics of these structures. We compare our results with those obtained in [21] from the discrete equation method for the case of a sharp waveguide bend. The comparison shows that neglecting the nonuniform field distribution inside the embedded nonlinear elements leads to overestimation of the waveguide bend tr…
During the last 2 years, it was shown that an electromagnetic beam configuration can be bent after propagation through an asymmetrically shaped (Janus) dielectric particle, which adds a new degree of simplicity for generation of a curved light beam. This effect is termed "photonic hook" (PH) and differs from Airy-family beams. PH features the smallest curvature radius of electromagnetic waves ever reported which is about 2 times smaller than the wavelength of the electromagnetic wave. The nature of a photonic hook is a the dispersion of the phase velocity of the waves inside a trapezoid or com…
We demonstrate the key role of the laser injection into a multimode fiber to obtain a photonic jet (PJ). PJ, a high concentrated propagating beam with a full width at half maximum smaller than the diffraction limit, is here generated with a shaped optical fiber tip using a pulsed laser source (1064~nm, 100~ns, 35~kHz). Three optical injection systems of light are compared. For similar etched marks on silicon with diameters around 1~$μ$m, we show that the required ablation energy is minimum when the injected light beam is close to the fundamental mode diameter of the fiber. Thus, we confirm exp…
The dispersion relation of plasma and plasma-dielectric photonic multilayer structures is approached in terms of a one-dimensional Particle-in-Cell simulation. For several plasma-dielectric configurations, the system response is obtained using a pulsed excitation and a subsequent two-dimensional frequency analysis. It is first shown that the dispersion relation of a single, homogeneous plasma slab is well described by the cold-plasma model even at low pressures of 1 Pa. The study is extended to the simulation of plasma photonic crystals with a variety of configurations, based on the work of Ho…
We present here our recent progress in the three-dimensional (3D) direct laser writing (DLW) of step-index core waveguides inside diverse technologically relevant dielectric substrates, with specific emphasis on the demonstration of DLW mid-infrared waveguiding in the whole transparency range of these materials.
Photonic lattices - arrays of optical waveguides - are powerful platforms for simulating a range of phenomena, including topological phases. While probing dynamics is possible in these systems, by reinterpreting the propagation direction as "time," accessing long timescales constitutes a severe experimental challenge. Here, we overcome this limitation by placing the photonic lattice in a cavity, which allows the optical state to evolve through the lattice multiple times. The accompanying detection method, which exploits a multi-pixel single-photon detector array, offers quasi-real time-resolve…
Films of graphene oxide (GO) were produced on the inner walls of glass microcapillaries via insertion of a GO water suspension followed by quick drying with a hot finger (no previous surface functionalization required). Individual capillaries from an array could also be selectively GO coated. Raman hyperspectral images revealed the films to be continuous along tens of centimeters. Furthermore, the films could be thermally reduced through an annealing process, which also decreased the concentration of defects. As a proof of principle application, the microcapillaries of photonic crystal fibers …
Orthogonal temporal modes (TMs) form a field-orthogonal, continuous-variable degree of freedom that is in principle infinite dimensional, and create a promising resource for quantum information science and technology. The ideal quantum pulse gate (QPG) is a device that multiplexes and demultiplexes temporally orthogonal optical pulses that have the same carrier frequency, spatial mode, and polarization. The QPG is the chief enabling technology for usage of orthogonal temporal modes as a basis for high-dimensional quantum information storage and processing. The greatest hurdle for QPG implement…
We report the existence of transversely stable soliton trains in optics. These stable soliton trains are found in two-dimensional square photonic lattices when they bifurcate from X-symmetry points with saddle-shaped diffraction inside the first Bloch band and their amplitudes are above a certain threshold. We also show that soliton trains with low amplitudes or bifurcated from edges of the first Bloch band (Gamma and M points) still suffer transverse instability. These results are obtained in the continuous lattice model and further corroborated by the discrete model.
We present an apparatus that converts every pulse of a pulsed light source to a pulse train in which the intensities of the different pulses are samples of the spatial or temporal frequency spectrum of the original pulse. In this way, the spectrum of the incident light can be measured by following the temporal response of a single detector. The apparatus is based on multiple round-trips inside a 2f- cavity-like mirror arrangement in which the spectrum is spread on the back focal plane, where after each round-trip a small section of the spectrum is allowed to escape. The apparatus is fibre-free…
We report on the rst evidence of direct micropeak machining using a photonic jet (PJ) with nanosecond laser pulses. PJ is a high concentrated propagative light beam with a full width at half maximum (FWHM) smaller than the diraction limit. In our case, PJs are generated with a shaped optical ber tip. Micropeaks with a FWHM of around 1 $μ$m, a height until 590 nm and an apex radius of 14 nm, were repeatability achieved on a silicon wafer. The experiments have been carried out in ambient air using a 100/140 multimode silica ber with a shaped tip along with a 35 kHz pulsed laser emitting 100 ns p…
