An ultrasensitive biosensor based on hybrid structure and composed of long-range surface plasmon polariton(LRSPP) and dielectric planar waveguide(PWG) modes is proposed. Both PWG and LRSPP modes have strong resonances...An ultrasensitive biosensor based on hybrid structure and composed of long-range surface plasmon polariton(LRSPP) and dielectric planar waveguide(PWG) modes is proposed. Both PWG and LRSPP modes have strong resonances to form strong coupling between the two modes, and the two modes can couple to enhance sensitivity of sensors. In the hybrid structure, PWG is composed of cytop–Si–cytop multilayers and the LRSPP configuration is composed of cytop–metal–sensing medium multilayer slabs. The highest imaging sensitivities of 2264 and3619 RIU-1were realized in the proposed sensors based on Au and Al-monolayer graphene, respectively, which are nearly 1.2 and 1.9 times larger than the 1910 RIU-1sensitivity of the conventional LRSPR sensor(LRSPP sensor). Moreover, it is demonstrated that the PWG-coupled LRSPP biosensor is applicable to the sensing medium,with refractive index in the vicinity of 1.34.展开更多
The guided and leaky modes of a planar dielectric waveguide are eigensolutions of a singular Sturm-Liouville problem. The modes are the roots of a characteristicfunction which can be found with several methods that ha...The guided and leaky modes of a planar dielectric waveguide are eigensolutions of a singular Sturm-Liouville problem. The modes are the roots of a characteristicfunction which can be found with several methods that have been introduced in thepast. However, the evaluation of the characteristic function suffers from numericalinstabilities, and hence it is often difficult to find all modes in a given range. Here anew variational formulation is introduced, which, after discretization, leads either to aquadratic or a quartic eigenvalue problem. The modes can be computed with standardsoftware for polynomial eigenproblems. Numerical examples show that the method isnumerically stable and guarantees a complete set of solutions.展开更多
Plasmonic waveguides and conventional dielectric waveguides have favorable characteristics in photonic integrated circuits. Typically, plasmonic waveguides can provide subwavelength mode confinement, as shown by their...Plasmonic waveguides and conventional dielectric waveguides have favorable characteristics in photonic integrated circuits. Typically, plasmonic waveguides can provide subwavelength mode confinement, as shown by their small mode area, whereas conventional dielectric waveguides guide light with low loss, as shown by their long propagation length. However, the simultaneous achievement of subwavelength mode confinement and low-loss propagation remains limited. In this paper, we propose a novel design of an all- dielectric bowtie waveguide, which simultaneously exhibits both subwavelength mode confinement and theoretically lossless propagation. Contrary to traditional dielectric waveguides, where the guidance of light is based on total internal reflection, the principle of the all-dielectric bowtie waveguide is based on the combined use of the conservation of the normal component of the electric displacement and the tangential component of the electric field, such that it can achieve a mode area comparable to its plasmonic counterparts. The mode distribution in the all-dielectric bowtie waveguide can be precisely controlled by manipulating the geometric design. Our work shows that it is possible to achieve extreme light confinement by using dielectric instead of lossy metals.展开更多
A simple fabrication method of self-aligned ridge waveguides with dielectric side buffers is demonstrated on +Z-cut LiNbO3. The ridge waveguide is fabricated by a combination of the annealed proton exchange process an...A simple fabrication method of self-aligned ridge waveguides with dielectric side buffers is demonstrated on +Z-cut LiNbO3. The ridge waveguide is fabricated by a combination of the annealed proton exchange process and the proton-exchanged wet etching technique.展开更多
We obtain the photonic bands and intrinsic losses for the triangular lattice three-component two- dimensional (2D) photonic crystal (PhC) slabs by expanding the electromagnetic field on the basis of waveguide mode...We obtain the photonic bands and intrinsic losses for the triangular lattice three-component two- dimensional (2D) photonic crystal (PhC) slabs by expanding the electromagnetic field on the basis of waveguide modes of an effective homogeneous waveguide. The introduction of the third component into the 2D PhC slabs influences the photonic band structure and the intrinsic losses of the system. We examine the dependences of the band gap width and gap edge position on the interlayer dielectric constant and interlayer thickness. It is found that the gap edges shift to lower frequencies and the intrinsic losses of each band decrease with the increasing interlayer thickness or dielectric constant. During the design of the real PhC system, the effect of unintentional native oxide surface layer on the optical properties of 2D PhC slabs has to be taken into consideration. At the same time, intentional oxidization of macroporous PhC structure can be utilized to optimize the design.展开更多
基金National Natural Science Foundation of China(NSFC)(61505111)Guandong Natural Science Foundation(2015A030313549)+2 种基金Science and Technology Planning Project of Guangdong Province(2016B050501005)Science and Technology Project of Shenzhen(JCYJ20140828163633996,JCYJ20150324141711667)Natural Science Foundation of SZU(201452,201517,827-000051,827-000052,827-000059)
文摘An ultrasensitive biosensor based on hybrid structure and composed of long-range surface plasmon polariton(LRSPP) and dielectric planar waveguide(PWG) modes is proposed. Both PWG and LRSPP modes have strong resonances to form strong coupling between the two modes, and the two modes can couple to enhance sensitivity of sensors. In the hybrid structure, PWG is composed of cytop–Si–cytop multilayers and the LRSPP configuration is composed of cytop–metal–sensing medium multilayer slabs. The highest imaging sensitivities of 2264 and3619 RIU-1were realized in the proposed sensors based on Au and Al-monolayer graphene, respectively, which are nearly 1.2 and 1.9 times larger than the 1910 RIU-1sensitivity of the conventional LRSPR sensor(LRSPP sensor). Moreover, it is demonstrated that the PWG-coupled LRSPP biosensor is applicable to the sensing medium,with refractive index in the vicinity of 1.34.
文摘The guided and leaky modes of a planar dielectric waveguide are eigensolutions of a singular Sturm-Liouville problem. The modes are the roots of a characteristicfunction which can be found with several methods that have been introduced in thepast. However, the evaluation of the characteristic function suffers from numericalinstabilities, and hence it is often difficult to find all modes in a given range. Here anew variational formulation is introduced, which, after discretization, leads either to aquadratic or a quartic eigenvalue problem. The modes can be computed with standardsoftware for polynomial eigenproblems. Numerical examples show that the method isnumerically stable and guarantees a complete set of solutions.
基金This work was supported by the Na- tional Key Basic Research Program of China under Grant No. 2012CB922003, and the National Natural Science Foundation of China (NSFC) under Grant No. 61177053, and Anhui Provincial Natural Science Foundation under Grant No. 1508085SMA205.
文摘Plasmonic waveguides and conventional dielectric waveguides have favorable characteristics in photonic integrated circuits. Typically, plasmonic waveguides can provide subwavelength mode confinement, as shown by their small mode area, whereas conventional dielectric waveguides guide light with low loss, as shown by their long propagation length. However, the simultaneous achievement of subwavelength mode confinement and low-loss propagation remains limited. In this paper, we propose a novel design of an all- dielectric bowtie waveguide, which simultaneously exhibits both subwavelength mode confinement and theoretically lossless propagation. Contrary to traditional dielectric waveguides, where the guidance of light is based on total internal reflection, the principle of the all-dielectric bowtie waveguide is based on the combined use of the conservation of the normal component of the electric displacement and the tangential component of the electric field, such that it can achieve a mode area comparable to its plasmonic counterparts. The mode distribution in the all-dielectric bowtie waveguide can be precisely controlled by manipulating the geometric design. Our work shows that it is possible to achieve extreme light confinement by using dielectric instead of lossy metals.
文摘A simple fabrication method of self-aligned ridge waveguides with dielectric side buffers is demonstrated on +Z-cut LiNbO3. The ridge waveguide is fabricated by a combination of the annealed proton exchange process and the proton-exchanged wet etching technique.
基金supported in part by the National Natural Science Foundation of China (No. 60707001,60711140087)the National "973" Program of China(No. 2007CB310705)+4 种基金the National "863" Program of China (No. 2007AA01Z247)NCET (07-0110)PCSIRT(No. IRT0609)ISTCP (No. 2006DFA11040)P. R.China
文摘We obtain the photonic bands and intrinsic losses for the triangular lattice three-component two- dimensional (2D) photonic crystal (PhC) slabs by expanding the electromagnetic field on the basis of waveguide modes of an effective homogeneous waveguide. The introduction of the third component into the 2D PhC slabs influences the photonic band structure and the intrinsic losses of the system. We examine the dependences of the band gap width and gap edge position on the interlayer dielectric constant and interlayer thickness. It is found that the gap edges shift to lower frequencies and the intrinsic losses of each band decrease with the increasing interlayer thickness or dielectric constant. During the design of the real PhC system, the effect of unintentional native oxide surface layer on the optical properties of 2D PhC slabs has to be taken into consideration. At the same time, intentional oxidization of macroporous PhC structure can be utilized to optimize the design.