2D Photonic Structures Research Articles

Titania Enhanced Photocatalysis and Dye Giant Absorption in Nanoporous 1D Bragg Microcavities.

Light trapping effects are known to boost the photocatalytic degradation of organic molecules in 3D photonic structures of anatase titania (a-TiO2) with an inverse opal configuration. In the present work, we show that photocatalytic activity can also be enhanced in a-TiO2 thin films if they are incorporated within a nanoporous 1D optical resonant microcavity. We have designed and manufactured multilayer systems that, presenting a high open porosity to enable a straightforward diffusion of photodegradable molecules, provide light confinement effects at wavelengths around the absorption edge of photoactive a-TiO2. In brief, we have observed that a nanoporous 1D Bragg microcavity prepared by electron beam evaporation at oblique angles comprising a central defect layer of nanoporous a-TiO2 boosts the photocatalytic degradation of nitrobenzene and methyl orange dye solutions. The multilayer structure of the microcavity was designed to ensure the appearance of optical resonances at the a-TiO2 layer location and wavelengths around the absorption onset of this semiconductor. In this porous 1D Bragg microcavity, the diffusion constraints of molecules through the capping layers covering the a-TiO2 are effectively compensated by an increase in the photocatalytic activity due to the light confinement phenomena. We also report that the absorption coefficient of methyl orange dye solution infiltrated within the pore structure of the microcavity is exalted at the wavelengths of the corresponding optical resonances. This effect gives rise to a small but non-negligible visible light photodegradation of dye molecules. The possibilities of tailoring the design of 1D photonic systems to boost the photocatalytic activity of a-TiO2 are discussed.

Local piezoelectric properties of perforated ferroelectric barium–strontium titanate films

Objectives. Focused ion beam etching remains one of the most common methods for fabricating 2D photonic crystals and structures based on functional materials. This technique is quite well developed for semiconductors. But at the same time, the change in the properties of ferroelectric materials under the action of a focused ion beam, including parameters of distribution and switching of the polarization state under the action of an electric field, remains poorly studied. The purpose of this work is to determine the local piezoelectric parameters in perforated ferroelectric films of barium strontium titanate (Ba0.8Sr0.2TiO3) with ordered vertical air channels fabricated by focused ion beam etching.Methods. Experimental studies were conducted using piezoresponse force microscopy under applied electric field in planar geometry.Results. It is shown that the perforation of a ferroelectric film leads not only to the formation of significant inhomogeneities in the piezoelectric response distribution in the structure, but also to the noticeable increase in the magnitude of both the vertical and lateral components of the piezoresponse near the perforation holes. The calculation results showed that the greatest enhancement is observed for the lateral component of the piezoresponse: from 5 pm/V for a nonperforated film to 65 pm/V in the perforated area.Conclusions. The most probable mechanism for such a change in properties is the influence of a disturbed layer that occurs at the boundary and the inner surface of vertical air channels. The properties of this layer are due to two factors: amorphization of the structure as a result of the focused ion beam etching and the appearance of pinned domain states near the hole, leading to the formation of the complex piezoresponse distribution both at the hole boundary and in the gap between the perforations. The information obtained is important for understanding the peculiarities of the formation of local piezoelectric and ferroelectric responses in photonic crystals fabricated by focused ion beam etching, as well as for finding ways to control their state when an external electric field is applied.

Omnidirectional photonic band gaps in one-dimensional gradient refractive index photonic crystals considering linear and quadratic profiles

By using the transfer matrix formalism, in this work it is presented the study of the optical properties of 1D photonic structures constructed with M periods of bilayers of dielectric material and slabs with gradient refractive index (GRIN) profile of two types: linear and quadratic. By varying the profile parameters, preserving the average value of the refractive index for the GRIN slab, the results show the formation of new photonic band gaps whose bandwidths depends on the slope and the curvature of the linear and quadratic profile respectively. Also, it can be observed the formation of omnidirectional photonic bandgaps for the TE and TM polarizations, one for the linear profile and three for the quadratic one, for which their bandwidths depend linearly on the slope and the curvature of the GRIN profiles. It is expected that the presented results could be useful in the construction of optical devices based in their optical response under oblique incidence.

A proposal of 3D sensor for rapid detection of breast tumour cell using photonic structure

The present research proposes a method that can identify tumour cells present in the human breast with the help of a plasmon-based three-dimensional (3D) photonic structure. The mechanism of detection of cells (tumour or normal) is realised through the analysis of the photonic bandgap of the proposed copper-based plasmonic structure. Moreover, the plane-wave expansion technique is applied to find the solution of the Helmholtz equation that determines the band structure. In this process, three signals with frequencies of 0.5, 1.0 and 1.5 THz are allowed to impinge on the structure to obtain the required results. The detection of cells that may be normal or suffering from tumour is confirmed by the reflected signal from the 3D photonic structure. More precisely, the bandgap analysis suggests that the cell is cancerous (suffering from tumour) if the reflected signal falls within the blue regime. In contrast, if the signal received finds a place within the violet regime of the spectrum, then this is an indication of a normal cell.

1D reconfigurable bistable photonic device composed of phase change material for detection of reproductive female hormones

In this manuscript one-dimensional (1D) photonic biosensor (PQ) N GDG(PQ) N composed of phase change material (PCM) germanium antimony telluride (GST) has been studied in visible region of electromagnetic spectrum. This design is capable of label free recognition of reproductive hormones of female which are significant during reproductive process such as menstruation and parturition. The proposed structure is composed of an air cavity separated by two buffer layers of GST material. The GST buffer layers have been used to improve the sensing performance of the structure. The modified cavity associated with buffer GST layers is sandwiched between two 1D photonic structures (PS) (PQ) N . Both 1D PS are consisted of alternate material layers of SiO2 and Si of period 5. The transmission spectra of proposed design have been obtained by using transfer matrix method and MATLAB software. In this work the performance of the devise has been investigated for normal and oblique incidence corresponding to TE wave only under the influence of change of phases of GST. The mainstay of this research is focused on the tunable performance of proposed bio-sensing design due to switching between amorphous phase (aGST) and crystalline phase (cGST) of GST. Moreover how the change in the thickness of cavity region as well as angle of incidence corresponding to TE wave affects the performance of the design has also been studied. The sensitivity, quality factor and figure of merit values of the design have also been studied to get deep insight about the sensing capabilities of the proposed design under the influence of crystalline and amorphous phases of GST. Thus due to simple architecture and excellent switchable and reconfigurable characteristics, our structure works efficiently in industrial and biomedical refractive index based sensing applications.

Temperature distribution inside a porous silicon photonic mirror

Photonic devices require precise and high-cost procedures to evaluate their performance which is related to their temperature increase. The fundamental understanding of thermal phenomena, ergo measurement of temperature, inside radiation controlling devices is of great relevance to study their performance. In this paper, we carry out a comprehensive campaign of experiments to study the temperature profile inside a porous silicon multilayer 1D photonic structure by using a thermographic camera. In particular, we have analyzed broad-range reflective devices and found that the electromagnetic radiation does not travel beyond the photonic structure showing a clear maximum inside of it. We have compared this result with a pure silicon wafer under the interaction with the same radiation. To compare these samples, we used a normalization procedure that can be implemented on many microstructured devices to simplify their performance evaluation.

Midinfrared Dispersion Relations in InP -Based Photonic Crystal Slabs Revealed by Fourier-Transform Angle-Resolved Reflection Spectroscopy

Photonic crystals (PCs) offer unique ways to control light-matter interactions. The measurement of dispersion relations is a fundamental prerequisite if we are to create novel functionalities in PC devices. Angle-resolved spectroscopic techniques are commonly used for characterizing PCs that work in the visible and near-infrared regions. However, the techniques cannot be applied to the mid- and long-wavelength infrared regions due to the limited sensitivity of infrared detectors. Here, we propose an alternative approach to measuring infrared dispersion relations. We construct a high-precision angle-resolved setup compatible with a Fourier-transform spectrometer with an angle resolution as high as 0.3 degrees. Hence, the reflection spectra are mapped to the 2D photonic band structures of In(Ga,Al)As/InP based PC slabs, which are designed as mid-infrared PC surface-emitting lasers. We identify complex PC modes with the aid of polarization selection rules derived by the group theory. Spectral analysis makes it possible to evaluate the mode quality (Q) factors. Therefore, angle-resolved reflection is a useful way of optimizing 2D PC parameters for mid-infrared devices.

Three Ways Chip to Chip Communication via a Single Photonic Structure: A Future Paragon of 3D Photonics to Optical VLSI

A proposal is made in this paper to realize 3-ways chip to chip communication via 3D photonic structure. The mechanism of the work is understood with the help of absorbance and reflectance of the structure. The absorbance is determined using the analytical treatment where reflectance is computed using the photonic bandgap analysis, which is found with the help of plane wave expansion method. Further the present research deals with low power input signal whose potential varies from 0.55 to 1 V because to avoid the heat generation in nanoelectronics and nanophotonic circuits where circuit comprises chip, LED and photo detector along with waveguide (3D photonic structure). The output results indicate that a proper combination of lattice spacing of silicon-based 3D photonic structure and diameter of air holes could be a right candidate to realise 3-ways communication.

Can liquid crystal Blue Phase textures be described by Voronoi tessellations?

ABSTRACT Algorithms are introduced and tested to calculate the nucleation sites of Blue Phase platelets from the experimental microscopic texture. Refinement of the algorithms leads to a methodology based on reversing Voronoi tessellations. This method is robust, concise and provides nucleation sites with a good accuracy. The experimental texture is then recreated by calculation of the respective Voronoi diagram using the previously determined sites. With the outlined method the formation of Blue Phase textures can very well be described to a similarity larger than 80%, yet its limitations are also discussed. The latter are mainly rooted in the finite platelet boundary width, occasional boundary curvature and inevitable temperature fluctuations during the experimental texture acquisition. The outlined procedure can, for example, be used for the prediction of complex 2D photonic structures based on the growth of specific BP lattice planes through seeded nucleation patterns on substrates.

Realization of novel corona virus kit using silicon based 2D photonic structure via finite difference time domain method.

The present research proposes the novel corona virus kit using silicon based two (2D) photonic structure. The basic principle of the estimation of different corona viruses relies on the computation of reflectance, absorbance, and transmittance at the signal of 412 nm. Here reflectance is investigated through the analysis of photonic band gap where absorbance is calculated using analytical treatment. The present investigation is made for different corona virus such as N5H1, N5H2, H9N2, H4N6, FAdV, and IBV. The numerical analysis indicates that the sample could be affected by novel corona virus if the transmitted signal lies with red spectrum. Similarly, sample could be normal viruses if the transmitted signal would green spectrum

A proposal for testing kit of corona viruses using 3D photonic structure.

Design of corona virus testing kit is proposed in this paper using silicon based 3D photonic structure through zirconium quantum dot solution at the signal of 412 nm. The principle of measurement depends on the computation of reflectance, absorbance and transmittance of virus based quantum dot solution. In this paper, the reflectance is studied through the analysis of photonic band gap and absorbance is made through its numerical treatment. Further, the numerical investigation shows that the transmitted energy through photonic structure would determine the type of corona virus. For example; if the transmitted energy lies within the visible spectrum the sample would be normal corona virus. However, the sample could be IBV (SARS COV-2) if the transmitted energy would be Infrared.

Recent Progress on Advanced Optical Structures for Emerging Photovoltaics and Photodetectors

Organic‐ and perovskite‐based optoelectronics, which merge excellent optoelectronic properties with potentially large and high‐throughput manufacturing, have attracted attention as emerging revolutionary technologies with considerable practical applications. Herein, the recent progresses in organic‐ and perovskite‐based photovoltaics and photodetectors with integration of judicious optical structure designs are summarized. The characterization and performance metrics of such devices from the perspectives of device architecture, physics, and material science are studied. Research related to devices having dielectric mirrors, diffracted Bragg reflectors/photonic crystals, microcavities, and 2D photonic structures as design elements is discussed. Some suggestions of promising directions for future studies are concluded.

Improving the Efficiency of a Polymer Nanocomposite for Formation of Photon Structures by Means of Optical Recording

We present the results of investigation of conditions leading to optimization of an optical recording medium based on photosensitive urethane–acrylate nanocomposites containing silicone oxide nanoparticles that is used for efficient recording of Bragg gratings by means of multiple-beam interference. It is demonstrated that the choice of most efficient monomers and their concentration in the nanocomposite depending on their structure and the rate of polymerization, followed by finding optimal intensity of recording radiation for given composition, allows regulating the conditions for component diffusion thereby optimizing their redistribution in the recording medium and formation of regions with different values of refractive index. The results of the study can be used for creation of complex 2D and 3D photonic structures based on purposeful modification of light-sensitive polymer nanocomposites exhibiting various properties (luminescent, nonlinear-optical, etc.)

Bloch surface waves biosensing in the ultraviolet wavelength range – Bragg structure design for investigating protein adsorption by in situ Kretschmann-Raether ellipsometry

We designed a Bragg mirror structure with an SiO2 top layer to create a resonance in the ultraviolet wavelength range, near the absorption peak position of various proteins. We demonstrate that the wavelength of enhanced sensitivity can be adjusted by proper design of the 1D photonic structure. The possibility to design the wavelength of enhanced sensitivity supports measurements of better selectivity, optimized for the absorption of the target material. Since the width of the resonant peak in the reflectance spectra can be sharper than those of plasmonics, and they can be positioned at more favourable regions of the instrument and material (e.g., in terms of intensity or selectivity), the sensitivity can exceed those of plasmon-enhanced measurements. In this study we demonstrate the main features of the concept at the example of in situ spectroscopic ellipsometry of fibrinogen adsorption in the Kretschmann-Raether configuration. We realized a resonant peak with a full width at half maximum of 3 nm near the wavelength of 280 nm, which coincides with the absorption maximum of fibrinogen. The influence of depolarization and surface roughness on the measurements, and the potential for improving the current experimental detection limit of 45 pg/mm2 is also discussed.

High‐Resolution 3D Printed Photonic Waveguide Devices

AbstractPhotonic building blocks fabricated using two‐photon polymerization laser lithography are reported. 3D polymer structures are fabricated using a direct laser writing process with nonlinear two‐photon absorption in photosensitive material. The 3D photonic structures include 3D photonic waveguides, Bragg gratings, and resonators. In particular, high‐quality spiral and air‐bridge waveguides providing 3D light guiding beyond a single plane are demonstrated. Sub‐micrometer features as well as unique coupling interfaces with 1.6 dB coupling losses and large 3 dB bandwidth are also demonstrated. Experimental characterization reveals the good transmission performance of the fabricated photonic devices. In addition, the waveguides are demonstrated to support 30 Gb s−1 NRZ (nonreturn to zero) and 56 Gb s−1 PAM4 (pulse amplitude modulation 4) high‐speed data. Small power penalties of 0.7 dB for NRZ (BER = 10−12) and 1.5 dB for PAM4 (BER = 10−6) are obtained.

Focused ion beam milling for prototyping 2D and 3D photonic structures

Focused ion beam (FIB) milling is widely used in fields such as the semiconductor industry and materials science research. The direct writing and small feature size also make FIB milling attractive for rapid prototyping of novel photonic structures. In this manuscript, we describe in detail a FIB milling procedure which enables high-resolution fabrication of complex micro- and nanostructures with precise geometry control. Two different procedures (for 2D and 3D structures) are described and implemented on the tip of a glass optical fiber for fabricating diverse structures embedded on or below the tip surface. The procedures described here can be easily adjusted and implemented on any conductive or non-conductive substrate.

In English

One of the promising materials for the development of 2D photonic structures is macroporous silicon obtained using photoanodic etching. Presence of periodically located cylindrical pores divided by silicon columns provides large effective surface of samples and enhanced optical and photo-physical characteristics of macroporous silicon structures. In this paper, the near-IR light absorption oscillations of 2D macroporous silicon structures with microporous silicon layers, SiO 2 nanocoatings and CdTe, ZnO surface nanocrystals are studded taking into account the Wannier–Stark electro-optical effect. An analysis of the experimental absorption spectra was carried out within the model of the resonant electron scattering with infinite amplitude on impurity states in strong electric field, with difference between two resonant energies equaled to the step of Wannier–Stark ladder. The constant oscillation period specifies the realization of Wannier–Stark effect on the randomly distributed surface bonds on silicon-nanocoating interface. We compared the IR absorption oscillations in 2D macroporous silicon with surface nanocoatings, analyzed shifts and deviations of oscillation peaks. The coherence of the IR spectra oscillations increases with the decrease of surface state concentration and with the optimal area of contact of nanocrystals to the macropore surface. Thus, the shift of oscillations for ZnO nanoparticles with optimal size of nanocrystals (3.7–4.4 nm) leads to deviations of the oscillation peaks within 0.26–0.42 meV, the oscillation coherence reaches 0.25–0.4 %. The small broadening parameter of the Wannier–Stark ladder levels G = 0.3¸0.8 cm –1 equals to that for surface phonon polaritons measured in thin films of II-VI semiconductors. Controllability and coherence of the investigated system are determined by forming of coherent Wannier levels in a narrow triangular potential well formed by an electric field at the silicon-nanocoating interface. In addition, we have proposed a high coherent optical quantum computer based on the quantum Wannier-Stark electro-optical effect on a silicon matrix with macropores and a layer of nanocrystals on the macropore surface.

Aberrated moving soliton in nonlinear photonic crystal

ABSTRACTBased on computer simulation, we demonstrate the nonlinear localization of a femtosecond laser pulse energy in 1D- and 2D photonic structures at the inclined incidence of a beam (or several beams) on a face of the photonic structure consisting of layers or rectangular elements. We show that, in 1D photonic crystal (PC), the energy localization is due to the formation of the moving soliton with the aberrated wave front – the aberrated soliton, which moves inside the photonic structure, being reflected many times from the PC faces, and its appearance depends on the photonic structure elements, ambient medium and the incident laser pulse shape. The dependence of the light energy localization on the sizes of the rectangular elements is investigated. We demonstrate controlling the light energy localization due to the incidence of several beams on the photonic structure and discuss the possibility of observing the described phenomena in a physical experiment.

Generation of UV Signal using 1D Photonic Structure: A Proposal to Photonic Industry for Designing Laser Torch

Ultraviolet (UV) signal pertaining to the visible spectrum is generated here using silicon based 1D photonic structure. Here optical band gap analysis is a basic principle of the same. Moreover the proposed structure operates with the absorption loss of the signal, which is found to be zero with reference to the input signal. The outcomes of the present paper deals with the generation of the Ultraviolet Signal of 240 nm to 280 nm, which is useful for killing of germs in the water. Further such signal could be used in the water purification. Finally, a schematic diagram for the realisation of Laser Torch is proposed which could be designed at the industry level to understand in its physical form.

Chip to Chip Communication at Three Windows: A Proposed Optical Device to VLSI Industry

One way chip to chip communication is proposed in the present paper with respect to the three windows. The principle of realisation is made through optical band gap analysis of 1D photonic structure .The same band gap is originated with the help of FTDT (finite difference time domain method). Finally the outcomes of simulated result inferred that the one way communication with respect to the electronic signal of 1.455 V, 0.95 V and 0.8 V corresponding to the 1st, 2nd and 3rd optical windows respectively. The present device would be inculcated in the VLSI chip, if it could be designed at the industry level of VLSI.