Composite Photonic Structure Research Articles

Microsecond All-Optical Modulation by Biofunctionalized Porous Silicon Microcavity.

We successfully created a composite photonic structure out of porous silicon (PSi) microcavities doped by the photochromic protein, photoactive yellow protein (PYP). Massive incorporation of the protein molecules into the pores was substantiated by a 30 nm shift of the resonance dip upon functionalization, and light-induced reflectance changes of the device due to the protein photocycle were recorded. Model calculations for the photonic properties of the device were consistent with earlier results on the nonlinear optical properties of the protein, whose degree of incorporation into the PSi structure was also estimated. The successful proof-of-concept results are discussed in light of possible practical applications in the future.

The Direction-Dependent Dual-Mechanism Sensor Based on Graphene Surface Plasmon Polariton and Composite Photonic Structure With Black Phosphorus

The direction-dependent dual-mechanism refractive index sensor composed of the forward strip graphene and backward composite photonic structure with black phosphorus (BP) is proposed. The linear correlation between the absorption by different mechanisms and the refractive index of the analyte can be realized for two incident directions. The simulated results show that the sensitivities of the forward incidence with the refractive index measurement ranges of 1.2 - 1.6 and 1.6 - 1.9 are 3.135 THz/RIU (refractive index unit) and 1.135 THz/RIU. The sensitivities of the backward incidence with refractive index detection zones 1.2 - 1.5 and 1.6 - 2.0 are 9.500 THz/RIU and 14.650 THz/RIU. In addition, the forward incidence owns more appropriate linearity while the backward incidence possesses better angular stability. These results can find applications in reconfigurable integrated photodetectors for refractive index sensing.

Composite photonic structures based on multi-beam double-cone interference

In this article, a multi-beam double-cone interference method is used to design and experimentally observe complex periodic lattices. By adjusting the cone angle and tangential angle of the inner-cone beams, we can design double-period graded photonic superlattice and composite photonic lattices with different unit cells. At the same time, Fourier transforming patterns of photonic lattices are given to provide a deep understanding of the changes of the lattice structures. Finally, double-period graded photonic structures are observed by multi-fiber interference, which further verifies our theoretical assumption. This investigation provides a new idea to broaden the application of photonic structures in integrated optical devices.

Temperature tunable optical transmission using IR based 1D photonic crystals of VO2 nanostructures

The effect of 1D photonic crystals on the optical transmission of VO2 is studied by depositing thin films of VO2 nanoparticles on SiO2/TiO2 distributed Bragg reflectors (DBRs) in the near-infrared (IR) spectrum as per the earlier theoretical predictions of Rashidi et al (2018 J. Phys. D: Appl. Phys. 51 375102). Monoclinic VO2 nanoparticles with tuned crystallinity are synthesized using a facile solution processing method. Moderately crystalline (MC) and highly crystalline (HC) VO2 nanostructures are obtained by varying the synthesis temperature and post-growth annealing conditions. Both the MC VO2 and HC VO2 films exhibit the expected reduction in optical transmission in the IR region due to the structural phase transition from monoclinic (insulator) to rutile (metallic) around the critical temperature of 68 °C. By combining VO2 films on a 40% transmitting DBR structure, the average optical transmission decreases further to ~20%. The number of stacks of DBRs plays a key role in such an effective reduction of optical transmission in the IR. When the number of stacks of DBRs is further increased from 4 to 7, the optical transmission of metallic VO2 films on DBRs nearly vanishes in the near-IR spectrum in such vanadium dioxide 1D photonic crystal based composite photonic structures. Such a temperature-controlled, enhanced, broad band optical response could provide a promising design for VO2 nanoparticle based hybrid photonic absorbers for various smart window applications.

Tunable interface state in one dimensional composite photonic structure

Based on the Transfer Matrix method (TMM), we evaluate the conditions and controllability of interface states in one-dimensional photonic structures composed of two binary layered photonic crystals, PCI and PCII, having the same photonic bandgaps but different unit cells. For PCs with inversion symmetry but different symmetry centers, the composite photonic structure exhibits interface states in the middle of the corresponding bandgaps where the sum of the reflection phases of the PCs is zero. The observed interface states persist even when the inversion symmetry is broken by shifting the unit cell of the individual PC as long as the sum of the reflection phases is still zero. Moreover, the location of interface states inside the bandgaps can be controlled by adjusting the thicknesses of the adjacent layers at the interface of two PCs. The composite photonic structure can be realized easily by standard electron beam evaporation technology, opening more possible applications in multi-channel narrowband filters and other optical modulation devices.

Nonreciprocity in Photonic Structures with Phase-Change Components

We consider the scattering problem for an asymmetric composite photonic structure with a component experiencing a thermally driven phase transition. Using a numerical example, we show that if the heating is caused by the incident light, the transmittance can become highly asymmetric within a broad range of light intensities. This effect can be utilized for directional light transmission, asymmetric optical limiting, or power switching.

Janus Structural Color from a 2D Photonic Crystal Hybrid with a Fabry–Perot Cavity

AbstractStructural colors are widely applied for their stability and their sophisticated optical responses. However, these colors always appear washed‐out or pale assigning to the defect hardly avoided in the manufacturing procedures. It is still a challenge to bring multifunctional vivid color via a facile method. A composite structure combining 2D photonic crystal and Fabry–Perot cavity by a simple and convenient method is constructed here. Various metallic colors with tunable hue and high saturation are produced by the composite structure. What is more, an obvious optical Janus effect is created by the composite structure. Iridescent colors can be observed when viewing from the same side of incident light but only pale colors can be seen from the opposite side. The hues and saturation of the colors can be adjusted by the parameters of the composite structure. The experimental results indicate that the color is derived from the synergistic effect of the interference, the diffraction, and the Rayleigh scattering of the composite structure. The facile composite photonic structure pioneers a new way for art, architecture, and security features in anticounterfeiting materials.

Surface plasmon-enhanced optical absorption in monolayer MoS2 with one-dimensional Au grating

The optical absorption of a composite photonic structure, namely monolayer molybdenum disulfide (MoS2)-covered Au grating, is theoretically investigated using a rigorous coupled-wave analysis algorithm. The enhancement of localized electromagnetic field due to surface plasmon polaritons supported by Au grating can be utilized to enhance the absorption of MoS2. The remarkable enhancement of absorption due to exciton transition can also be realized. When the period of grating is 600 nm, the local absorption of the monolayer MoS2 on Au grating is nearly 7 times higher than the intrinsic absorption due to B exciton transition. A further study reveals that the absorption properties of Au grating can be tailored by altering number of MoS2 layers, changing to a MoS2 nanoribbon array, and inserting a hafnium dioxide (HfO2) spacer. This work will contribute to the design of MoS2-based optical and optoelectronic devices.

Mesoscopic photonic structures in glasses by femtosecond-laser fashioned confinement of semiconductor quantum dots

Optically tunable mesoscale structures offer unparalleled potential for photonic device applications. Here, we report the creation of composite photonic structures consisting of CdSxSe1−x quantum dots (QDs) customized within lines, first written in a glass by femtosecond laser pulses. CdSxSe1−x-doped borosilicate glasses were pulsed with a fs-laser using a 473 kHz repetition rate to create chemically distinct microscopic regions. Upon further heat treatment, these regions served as “micro-crucibles” within which quantum dots were precipitated exclusively. These results open prospects of developing other semiconductor doped glasses for versatile photonic structures useful over broader optical wavelengths.

Theoretical demonstration of highly efficient cw THz generation by using composite photonic-structure elements

We theoretically propose one-dimensional composite photonic structures for high-resolution THz spectroanalysis. We compare the performance of two GaAs/AlAs composite photonic-structure devices, one with usual 1/4-wavelength layers of distributed Bragg reflectors (DBRs), and the other with the designed DBRs. The device with designed DBRs shows the optical-to-terahertz conversion efficiency up to 10−5 and wide frequency tunability ranging from sub-THz to 3 THz. We found that the composite photonic structure allows us to control photonic modes with a high degree of freedom by flexible structure designs. This device achieve a cw THz source with a highly narrow bandwidth operating at room temperature.

Proposal of composite photonic structure element for efficient terahertz generation

AbstractIn this study, we propose new terahertz generation method. When we inject pump and signal wave into periodic multilayer structure obliquely (abstract figure), transmission resonant mode splits into two modes, i.e. p‐polarized mode and s‐polarized mode. By using two modes for difference frequency generation (DFG), THz wave can generate. As a result of theoretical calculation, composite photonic structure shows high performance, i.e. the conversion efficiency up to 10‐3% and wide tuneable frequency ranging from a few hundred of GHz to 3 THz. Further, the thickness of this element is order of a few micrometers that includes resonator mirror parts and total optical system can become compact size. This scheme has potential to achieve tuneable continuous wave (cw) THz source at room temperature. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Electrotunable in-plane one-dimensional photonic structure based on silicon and liquid crystal

The model of the electro-optical effect, due to the reorientation of liquid crystal molecules from a pseudoisotropic to a homeotropic state, in a composite photonic structure with a liquid crystal filler, is elaborated. A composite (110) grooved silicon photonic structure for the middle infrared range was designed and fabricated on a silicon-on-insulator platform. Polarized reflection spectra, demonstrating the electro-optical effect, have been obtained by means of Fourier transform infrared microscopy. The relative shift of the band edge at half intensity in the region of 10μm was found experimentally to be 1.6% compared to 2.2% as predicted by theory.