L3型二维平板光子晶体微腔品质因数优化

二维平板光子晶体微腔在垂直于平板方向上存在辐射损耗,使得微腔品质因数不够大,限制了其应用。结合光子晶体微腔损耗的傅里叶分析,采用调整腔模空间分布的方法,减少了波矢在辐射泄漏区域的分布,进而降低了腔损耗,实现了微腔品质因数的优化。针对L3型二维光晶体微腔的结构设计,对具体的L3型光子晶体微腔优化进行了数值仿真,仿真结果表明微腔品质因数得到了极大的提高,验证了光子晶体微腔品质因数优化方法的有效性。     

一维光子晶体完全光子禁带与结构的关系

阐述了完全光子禁带的概念.用光学特征矩阵方法,通过数值模拟计算,讨论了一维光子晶体出现完全光子禁带与晶体结构和介质材料的折射率的密切关系.具体计算了用同样两种介质材料组成3种不同结构的一维光子晶体,对于TM及TE电磁模式在不同入射角下的透射率谱,从中找出它们的完全光子禁带,发现3种结构的完全光子禁带的波长范围及宽度各不相同.另外,研究结果表明组成光子晶体的两种材料的折射率差别越大,两种电磁模的禁带越宽,越容易产生完全光子禁带.简单讨论了完全光子禁带出现的条件.     

光子晶体传感器的研究进展

光子晶体是一类具有光子能带和带隙的新型光学材料,近年来已成为传感器技术领域的研究热点。光子晶体微腔、光子晶体波导、光子晶体光纤在传感器领域得到了广泛应用,而凝胶光子晶体、反蛋白石光子晶体、分子印迹光子晶体则实现了化学生物传感器的"裸眼检测技术"。重点分类介绍了一维、二维、三维光子晶体的制备及其在传感器领域的应用进展。     

关于新的阶梯型函数光子晶体的研究

研究了一维阶梯型函数光子晶体,给出色散关系和透射率的表达式,并与常规光子晶体比较,发现在常规光子晶体中加入缺陷层后,出现明显的缺陷模。而在阶梯型函数光子晶体中加入缺陷层后,缺陷模个数少且强度弱。进一步研究了带缺陷和不带缺陷的阶梯型函数光子晶体的光场分布。发现有缺陷层时,光场强度分布得到增强或者减弱,不同于常规光子晶体中的光强只局域增强。函数光子晶体的这些新的特性对光子晶体的设计与应用具有重要的实际意义。     

多通道光子晶体器件设计

一维光子晶体缺陷模的光谱特性与缺陷模的结构紧密相关.当缺陷模中包含有多个缺陷时,将导致光子禁带中出现多个分立的缺陷能级,形成多个透射光通道.利用一维光子晶体缺陷模这一光谱特性设计了红外谱段的三通道光子晶体器件.     

光子晶体应用研究进展

光子晶体是一种具有光子带隙的新型材料,其概念提出比较早,距今已经过了30年。由于光子晶体具有很多新颖的特性,使其成为微纳光子学和量子光学的重要研究领域。随着微加工技术的进步和理论的深入研究,光子晶体在信息光学以及多功能传感器等其他多个学科中也得到广泛应用。本文从理论上详细综述了光子晶体的各种奇异特性,并从各种特性出发,详细介绍近年来光子晶体在光子晶体光纤、反射镜、滤波器、波导、低阈值激光器、多功能传感器、腔量子电动力学、偏振器、量子信息处理等领域的应用研究,并与传统的器件进行性能比较得出光子晶体器件具有无可比拟的优势。最后提出,随着3D打印制造技术的成熟,光子晶体材料必然会推动信息技术的新一轮革命。     

光子晶体应用研究进展

光子晶体是一种具有光子带隙的新型材料,其概念提出比较早,距今已经过了30年。由于光子晶体具有很多新颖的特性,使其成为微纳光子学和量子光学的重要研究领域。随着微加工技术的进步和理论的深入研究,光子晶体在信息光学以及多功能传感器等其他多个学科中也得到广泛应用。本文从理论上详细综述了光子晶体的各种奇异特性,并从各种特性出发,详细介绍近年来光子晶体在光子晶体光纤、反射镜、滤波器、波导、低阈值激光器、多功能传感器、腔量子电动力学、偏振器、量子信息处理等领域的应用研究,并与传统的器件进行性能比较得出光子晶体器件具有无可比拟的优势。最后提出,随着3D打印制造技术的成熟,光子晶体材料必然会推动信息技术的新一轮革命。     

面向硅基光互连应用的无源光子集成器件研究进展

光互连是突破传统微电子IC性能瓶颈的重要技术手段,对推进"后摩尔时代"微电子技术的发展和高性能计算技术的实现具有关键性意义。本文在归纳总结不同层次光互连结构特点的基础上,对片上光互连(on-chip or intra-chip optical interconnects)所涉及的若干种无源光子集成器件的设计制备及性能特点进行了分析介绍,这些器件包括SOI亚波长光子线波导、SOI光子晶体波导、MMI分束/合束器、微环/微盘谐振腔滤波器、光子晶体微腔耦合滤波器、光子晶体反射镜等,是硅基片上光互连的基本构成单元。本文对这些关键性光子集成器件的国内最新研究进展进行了报道。     

用遗传算法搜索一维光子晶体带隙

利用遗传算法和传输矩阵法计算一维光子晶体能带结构,将一维光子晶体用像素填充法进行二进制编码模拟,结果找到全方位相对禁带宽度达42.54%的4层结构和43.75%的2层结构;给出了一维光子晶体4层最佳结构的能带图、20个原胞的反射率透射率频谱图.发现一维2层光子晶体的全方位禁带宽度对每层厚度的变化是不敏感的,但是随着两种介质折射率差的增大而增大.     

棱镜耦合光子晶体表面波及其传感特性研究

构造一种棱镜耦合一维光子晶体结构,利用传输矩阵方法对该结构中光的传输特性进行研究.结果表明:光在这种棱镜耦合一维光子晶体结构中传播时,会在光子晶体表面产生非辐射传播模,即表面波,而且在反射谱中表面波所在的角度位置、反射率的大小以及反射峰的半峰全宽受到一维光子晶体的介质折射率和介质厚度的调制.此外,表面波对应的角度位置对...     

Photonic Crystal Hydrogel Enhanced Plasmonic Staining for Multiplexed Protein Analysis

Plasmonic nanoparticles are commonly used as optical transducers in sensing applications. The optical signals resulting from the interaction of analytes and plamsonic nanoparticles are influenced by surrounding physical structures where the nanoparticles are located. This paper proposes inverse opal photonic crystal hydrogel as 3D structure to improve Raman signals from plasmonic staining. By hybridization of the plasmonic nanoparticles and photonic crystal, surface‐enhanced Raman spectroscopy (SERS) analysis of multiplexed protein is realized. It benefits the Raman analysis by providing high‐density “hot spots” in 3D and extra enhancement of local electromagnetic field at the band edge of PhC with periodic refractive index distribution. The strong interaction of light and the hybrid 3D nanostructure offers new insights into plasmonic nanoparticle applications and biosensor design.     

Photonic crystal-based RGB primary colour optical filter

Abstract

We have presented an RGB optical filter, based on photonic crystal (PhC) waveguides, with the hexagonal arrangement of GaP rods in air. It filters out the three primary colours of the visible range, red (R, λ = 648 nm), green (G, λ = 540 nm) and blue (B, λ = 470 nm). The plane wave expansion method is applied for estimating the dispersion curves and finite element method is utilized in examining the propagation characteristics of the designed PhC-based optical filter. Transmittance, extinction ratio and tolerance analysis have further been calculated to confirm the performance of the proposed optical filter to work in the visible range of optical spectrum and filter out the three primary colours (red, green, blue) along different output ports.     

Hybrid genetic optimization for design of photonic crystal emitters

A unique hybrid-optimization technique is proposed, based on genetic algorithms (GA) and gradient descent (GD) methods, for the smart design of photonic crystal (PhC) emitters. The photonic simulation is described and the granularity of photonic crystal dimensions is considered. An innovative sliding-window method for performing local heuristic search is demonstrated. Finally, the application of the proposed method on two case studies for the design of a multi-pixel photonic crystal emitter and the design of thermal emitter in thermal photovoltaic is demonstrated. Discussion in the report includes the ability of the optimal PhC structures designed using the proposed method, to produce unprecedented high emission efficiencies of 54.5% in a significantly long wavelength region and 84.9% at significantly short wavelength region.     

Inkjet‐Printed Nanocavities on a Photonic Crystal Template

The last decade has witnessed the rapid development of inkjet printing as an attractive bottom‐up microfabrication technology due to its simplicity and potentially low cost. The wealth of printable materials has been key to its widespread adoption in organic optoelectronics and biotechnology. However, its implementation in nanophotonics has so far been limited by the coarse resolution of conventional inkjet‐printing methods. In addition, the low refractive index of organic materials prevents the use of “soft‐photonics” in applications where strong light confinement is required. This study introduces a hybrid approach for creating and fine tuning high‐Q nanocavities, involving the local deposition of an organic ink on the surface of an inorganic 2D photonic crystal template using a commercially available high‐resolution inkjet printer. The controllability of this approach is demonstrated by tuning the resonance of the printed nanocavities by the number of printer passes and by the fabrication of photonic crystal molecules with controllable splitting. The versatility of this method is evidenced by the realization of nanocavities obtained by surface deposition on a blank photonic crystal. A new method for a free‐form, high‐density, material‐independent, and high‐throughput fabrication technique is thus established with a manifold of opportunities in photonic applications.     

Photonic Crystal Phosphors Integrated on a Blue LED Chip for Efficient White Light Generation

Following the proof‐of‐concept experiment in the unit structure level, photonic crystal (PhC) phosphors—structurally engineered phosphor materials based on the nanophotonics principles—are integrated with a blue light‐emitting diode (LED) chip to demonstrate a compact and efficient white light source. Red‐ or green‐emitting CdSe‐based colloidal quantum dots (CQDs) are coated on a Si₃N₄ thin‐film grating to fabricate PhC phosphors. The underlying PhC structure is designed such that the photonic band‐edge modes at the zone center (k_∣∣ = 0) are tuned to the energy of the blue excitation photons. By progressively stacking the PhC phosphor plates on a blue LED chip, the blue, green, and red emission intensities can be tightly controlled to obtain white light with the desired properties. The chromaticity coordinates, (0.332, 0.341), and correlated color temperature, 5500 K, are obtained from a stack of 3 red and 11 green PhC phosphor plates; in contrast, a stack of 5 red and 16 green reference phosphor plates are required to generate a similar white light. Overall, the PhC phosphors produce 8% higher total emission intensity out of 33% less amount of CQDs than the reference phosphors.     

Enlarged Photonic Band Gap in Heterostructure of Metallic Photonic and Superconducting Photonic Crystals

We show theoretically that the frequency range of photonic band gap of a hetero-structure which is made of a metallic photonic and superconducting photonic crystal can be enlarged due to the combination of the reflection band properties of the superconductor–dielectric (PC1) and metallic–dielectric (PC2) periodic structures. The transmittance and band structure of the considered structures are calculated using simple transfer matrix method and the Bloch theorem. Beside this, we have also calculated the transmittance of the superconducting photonic structure (PC1), metallic photonic structure (PC2) and heterostructure of metallic photonic and superconductor photonic crystals (PC1/PC2) for TE and TM-mode at the different angles of incidence.     

Fano-Like Resonance from Disorder Correlation in Vacancy-Doped Photonic Crystals

By preparing colloidal crystals with random missing scatterers, crystals are created where disorder is embodied as vacancies in an otherwise perfect lattice. In this special system, there is a critical defect concentration where light propagation undergoes a transition from an all but perfect reflector (for the spectral range defined by the Bragg condition), to a metamaterial exhibiting an enhanced transmission phenomenon. It is shown that this behavior can be phenomenologically described in terms of Fano-like resonances. The results show that the Fano's parameter q experiences a sign change signaling the transition from a perfect crystal exhibiting a reflectance Bragg peak, through a state where background scattering is maximum and Bragg reflectance reaches a minimum to a point where the system reenters a low scattering state recovering ordinary Bragg diffraction. A simple dipolar model considering the correlation between scatterers and vacancies is proposed and the reported evolution of the Fano-like scattering is explained in terms of the emerging covariance between the optical paths and polarizabilities and the effect of field enhancement in photonic crystal (PhC) defects.     

光子晶体光纤光栅反射谱及时延特性研究

利用多极法对包层空气孔为正六边形对称结构光子晶体光纤的模式场进行了分析,计算出不同波长下基模的有效折射率,结合使用模式耦合理论和传输矩阵法对基于光子晶体光纤的布拉格光栅特性进行了计算和仿真,对比了常规单模光纤所成光栅与相同光栅周期的光子晶体光纤布拉格光栅反射谱及时延特性之间的差异.在此基础上,对光纤光栅的切趾特性进行了研究,选择不同的切趾函数,得出最佳切趾函数下光栅传输谱.理论计算和仿真结果表明,随波长增加,基模有效折射率下降,光栅谐振波长出现蓝移,采用啁啾化处理后,10 cm长光子晶体光纤光栅可以提供1 200 ps以上的线性时延.     

Nonlinear optical responses in two-dimensional photonic crystals

A two-dimensional (2D) highly nonlinear lithium niobate (LN) photonic crystal (PhC) waveguide is fabricated with the aim of studying its nonlinear optical properties. We show a large enhancement of the second-harmonic generation (SHG) in the 2D LN PhCs, originating from resonance between the external pump laser field and a photonic band mode. The SHG enhancement results agree well with the experimental photonic band structure obtained by an angle-dependent optical reflectivity and the theoretical band structure generated by three-dimensional finite-difference time-domain calculations. These results open new possibilities for the use of 2D LN PhC waveguide in integrated nonlinear optical applications.