Bloch surface waves（BSWs） are excited in one-dimensional photonic crystals（Ph Cs） terminated by a graphene monolayer under the Kretschmann configuration. The field distribution and reflectance spectra are numerica...Bloch surface waves（BSWs） are excited in one-dimensional photonic crystals（Ph Cs） terminated by a graphene monolayer under the Kretschmann configuration. The field distribution and reflectance spectra are numerically calculated by the transverse magnetic method under transfer-matrix polarization, while the sensitivity is analyzed and compared with those of the surface plasmon resonance sensing method. It is found that the intensity of magnetic field is considerably enhanced in the region of the terminated layer of the multilayer stacks, and that BSW resonance appears only in the interface of the graphene and solution. Influences of the graphene layers and the thickness of a unit cell in Ph Cs on the reflectance are studied as well. In particular, by analyzing the performance of BSW sensors with the graphene monolayer,the wavelength sensitivity of the proposed sensor is 1040 nm/RIU whereas the angular sensitivity is 25.1°/RIU. In addition,the maximum of figure of merit can reach as high as 3000 RIU^-1. Thus, by integrating graphene in a simple Kretschmann structure, one can obtain an enhancement of the light–graphene interaction, which is prospective for creating label-free,low-cost and high-sensitivity optical biosensors.展开更多
Photonic crystal based ring resonators are best choice for designing all-optical devices. In this paper, we used a basic structure of photonic crystal ring resonators and designed all optical logic gates which are wor...Photonic crystal based ring resonators are best choice for designing all-optical devices. In this paper, we used a basic structure of photonic crystal ring resonators and designed all optical logic gates which are working using the Kerr effect. The proposed gates consisted of upper and lower wavegnides coupled through a resonator which was designed for dropping of special wavelength. The resonance wavelength was designed for 1550 nm telecom operation wavelength. We used numerical meth- ods such as plane wave expansion and finite difference time domain （FDTD） for performing our simulations and studied the optical properties of the proposed structures. Our results showed that the critical input power for triggering the gate output was lower compared to previously reported gates.展开更多
Because of its very low light extraction efficiency(LEE),LED is limited to be widely used under the condition of the internal quantum efficiency which up to 90%.In order to fullfill the design of a more efficient GaN-...Because of its very low light extraction efficiency(LEE),LED is limited to be widely used under the condition of the internal quantum efficiency which up to 90%.In order to fullfill the design of a more efficient GaN-based blue light LED,the model including deeply etched surface photonic crystals(PhCs)LED is discussed using mode analysis method from light waveguide theory.The distributions of all order modes in GaN layer are obtained by the effective index approximation.The light extraction efficiencies are also calculated by finite-difference time-domain method(FDTD).The emulated results fully coincide with the former analysis.Because the manufacture of the surface photonic crystal is feasible,the work can be very meaningful to design and manufacture the high efficiency GaN-based blue light LED in factory for a large amount.展开更多
Si photonics becomes one of the research focuses in the field of photonics. Si-based light-emitting devices are one of the most important devices in this field. In this paper, we review the Si-based light-emitting dev...Si photonics becomes one of the research focuses in the field of photonics. Si-based light-emitting devices are one of the most important devices in this field. In this paper, we review the Si-based light-emitting devices fabricated by embedding Ge self-assembled quantum dots into optical microcavities. Ge self-assembled quantum dots emit light in the telecommunication wavelength range from 1.3 to 1.6 pro, for which Si is transparent. Ge self- assembled quantum dots were grown on silicon-on- insulator （SOI） by molecular beam epitaxy （MBE） in Stranski-Krastanov （S-K） mode. Then, electron beam lithography （EBL） was used to define the pattern of optical microcavities on the wafer. Finally, the pattern was transferred onto the Si/Ge slab by inductive coupled plasma （ICP） dry etching. Room-temperature photolumi- nescence （PL） was used to characterize the light-emitting properties of fabricated devices. The results showed that strong resonant light emission was observed in different optical microcavities. Significant enhancement of the intensity was obtained by the optical resonance. Based on the results of PL, we designed and fabricated current- injected light-emitting devices based on Ge self-assembled quantum dots in optical microcavities. Room-temperature resonant light emission was observed from Ge dots in a 3.8 μm microdisk resonator.展开更多
Photonic crystal （PhC） has offered a powerful means to mold the flow of light and manipulate light- matter interaction at subwavelength scale. Silicon has a large refraction index and low loss in infrared wavelength...Photonic crystal （PhC） has offered a powerful means to mold the flow of light and manipulate light- matter interaction at subwavelength scale. Silicon has a large refraction index and low loss in infrared wavelengths, which makes it an important optical material. And silicon has been widely used for integrated photonics applications. In this paper, we have reviewed some recent theoretical and experimental works in our group on infrared two- dimensional （2D） air-bridged silicon PhC slab devices that are based on both band gap and band structure engineering. We have designed, fabricated, and characterized a series of PhC waveguides with novel geometries, PhC high-quality （high-Q） cavity, and channel drop filters utilizing resonant coupling between waveguide and cavity. These devices are aimed to construct a more flexible network of transport channel for infrared light at micrometer/nanometer scale. We have also explored the remarkable dispersion proper- ties of PhCs by engineering the band structures to achieve negative refraction, self-collimation, superprism, and other anomalous dispersion behaviors of infrared light beam. Furthermore, we have designed and fabricated a PhC structure with negative refraction effect and used scanning near-field optical microscopy to observe the negative refraction beam. Finally, we have designed and realized a PhC structure that exhibits a self-collimation effect in a wide angle range and with a large bandwidth. Our works presented in this review show that PhCs have a strong power of controlling propagation of light at micrometer/ nanometer scale and possess a great potential of applications in integrated photonic circuits.展开更多
In this paper, the photonic band gap （PBG） properties of two dimensional （2D） square lattice photonic crystal structures composed of rectangular cells were studied. The effect of refractive index, rectangles lengt...In this paper, the photonic band gap （PBG） properties of two dimensional （2D） square lattice photonic crystal structures composed of rectangular cells were studied. The effect of refractive index, rectangles length and the ratio of width to length of the rectangles on the PBG properties of the structure with different configura- tions was investigated. It is found that the density of gaps in both modes （transverse electric （TE） and transverse magnetic （TM）） is high for structure composed of rectangular dielectric rods in gaps is very low for structure pores in dielectric material. air, while the density of the composed of rectangular air展开更多
In this paper, we presented switching dynamic investigations on an InP photonic-crystal （PhC） nanocavity structure using homodyne pump-probe measurements. The measurements were compared with simulations based on tem...In this paper, we presented switching dynamic investigations on an InP photonic-crystal （PhC） nanocavity structure using homodyne pump-probe measurements. The measurements were compared with simulations based on temporal nonlinear coupled mode theory and carrier rate equations for the dynamics of the carrier density governing the cavity properties. The results provide insight into the nonlinear optical processes that govern the dynamics of nanocavities.展开更多
In this work, the characteristics of the photonic crystal tunneling injection quantum dot vertical cavity surface emitting lasers（Ph C-TIQD-VCSEL） are studied through analyzing a modified modulation transfer functio...In this work, the characteristics of the photonic crystal tunneling injection quantum dot vertical cavity surface emitting lasers（Ph C-TIQD-VCSEL） are studied through analyzing a modified modulation transfer function. The function is based on the rate equations describing the carrier dynamics at different energy levels of dot and injector well. Although the frequency modulation response component associated with carrier dynamics in wetting layer（WL） and at excited state（ES） levels of dots limits the total bandwidth in conventional QD-VCSEL, our study shows that it can be compensated for by electron tunneling from the injector well into the dot in TIQD structure. Carrier back tunneling time is one of the most important parameters, and by increment of that, the bias current dependence of the total bandwidth will be insignificant. It is proved that at high bias current, the limitation of the WL-ES level plays an important role in reducing the total bandwidth and results in rollovers on 3-d B bandwidth-I curves. In such a way, for smaller air hole diameter of photonic crystal, the effect of this reduction is stronger.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61203211 and 41675154)the Six Major Talent Peak Expert of Jiangsu Province,China(Grant No.2015-XXRJ-014)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20141483)
文摘Bloch surface waves（BSWs） are excited in one-dimensional photonic crystals（Ph Cs） terminated by a graphene monolayer under the Kretschmann configuration. The field distribution and reflectance spectra are numerically calculated by the transverse magnetic method under transfer-matrix polarization, while the sensitivity is analyzed and compared with those of the surface plasmon resonance sensing method. It is found that the intensity of magnetic field is considerably enhanced in the region of the terminated layer of the multilayer stacks, and that BSW resonance appears only in the interface of the graphene and solution. Influences of the graphene layers and the thickness of a unit cell in Ph Cs on the reflectance are studied as well. In particular, by analyzing the performance of BSW sensors with the graphene monolayer,the wavelength sensitivity of the proposed sensor is 1040 nm/RIU whereas the angular sensitivity is 25.1°/RIU. In addition,the maximum of figure of merit can reach as high as 3000 RIU^-1. Thus, by integrating graphene in a simple Kretschmann structure, one can obtain an enhancement of the light–graphene interaction, which is prospective for creating label-free,low-cost and high-sensitivity optical biosensors.
文摘Photonic crystal based ring resonators are best choice for designing all-optical devices. In this paper, we used a basic structure of photonic crystal ring resonators and designed all optical logic gates which are working using the Kerr effect. The proposed gates consisted of upper and lower wavegnides coupled through a resonator which was designed for dropping of special wavelength. The resonance wavelength was designed for 1550 nm telecom operation wavelength. We used numerical meth- ods such as plane wave expansion and finite difference time domain （FDTD） for performing our simulations and studied the optical properties of the proposed structures. Our results showed that the critical input power for triggering the gate output was lower compared to previously reported gates.
基金National Natural Science Foundation of China(No.61071087)Reward Fund of Outstanding Youth and Middle Age Scientist of Shandong Province(No.BS2009N5002)
文摘Because of its very low light extraction efficiency(LEE),LED is limited to be widely used under the condition of the internal quantum efficiency which up to 90%.In order to fullfill the design of a more efficient GaN-based blue light LED,the model including deeply etched surface photonic crystals(PhCs)LED is discussed using mode analysis method from light waveguide theory.The distributions of all order modes in GaN layer are obtained by the effective index approximation.The light extraction efficiencies are also calculated by finite-difference time-domain method(FDTD).The emulated results fully coincide with the former analysis.Because the manufacture of the surface photonic crystal is feasible,the work can be very meaningful to design and manufacture the high efficiency GaN-based blue light LED in factory for a large amount.
基金Acknowledgements The authors would like to thank Prof. Usami from Tohoku University for his help in the growth of Ge quantum dots. This work was supported by the Fundamental Research Funds for the Central Universities of Huazhong University of Science and Technology （No. 2011TS022） and the National Natural Science Foundation of China （Grant No. 61177049）.
文摘Si photonics becomes one of the research focuses in the field of photonics. Si-based light-emitting devices are one of the most important devices in this field. In this paper, we review the Si-based light-emitting devices fabricated by embedding Ge self-assembled quantum dots into optical microcavities. Ge self-assembled quantum dots emit light in the telecommunication wavelength range from 1.3 to 1.6 pro, for which Si is transparent. Ge self- assembled quantum dots were grown on silicon-on- insulator （SOI） by molecular beam epitaxy （MBE） in Stranski-Krastanov （S-K） mode. Then, electron beam lithography （EBL） was used to define the pattern of optical microcavities on the wafer. Finally, the pattern was transferred onto the Si/Ge slab by inductive coupled plasma （ICP） dry etching. Room-temperature photolumi- nescence （PL） was used to characterize the light-emitting properties of fabricated devices. The results showed that strong resonant light emission was observed in different optical microcavities. Significant enhancement of the intensity was obtained by the optical resonance. Based on the results of PL, we designed and fabricated current- injected light-emitting devices based on Ge self-assembled quantum dots in optical microcavities. Room-temperature resonant light emission was observed from Ge dots in a 3.8 μm microdisk resonator.
基金Acknowledgements This work was supported by the National Key Basic Research Special Foundation of China （No. 2011CB922002）, the National Natural Science Foundation of China, and National Center for Nanoscience and Technology of China. The authors would like to thank the previous members of our group, Cheng Ren, Haihua Tao, Yazhao Liu, and Changzhu Zhou for their contributions to the works presented in this review.
文摘Photonic crystal （PhC） has offered a powerful means to mold the flow of light and manipulate light- matter interaction at subwavelength scale. Silicon has a large refraction index and low loss in infrared wavelengths, which makes it an important optical material. And silicon has been widely used for integrated photonics applications. In this paper, we have reviewed some recent theoretical and experimental works in our group on infrared two- dimensional （2D） air-bridged silicon PhC slab devices that are based on both band gap and band structure engineering. We have designed, fabricated, and characterized a series of PhC waveguides with novel geometries, PhC high-quality （high-Q） cavity, and channel drop filters utilizing resonant coupling between waveguide and cavity. These devices are aimed to construct a more flexible network of transport channel for infrared light at micrometer/nanometer scale. We have also explored the remarkable dispersion proper- ties of PhCs by engineering the band structures to achieve negative refraction, self-collimation, superprism, and other anomalous dispersion behaviors of infrared light beam. Furthermore, we have designed and fabricated a PhC structure with negative refraction effect and used scanning near-field optical microscopy to observe the negative refraction beam. Finally, we have designed and realized a PhC structure that exhibits a self-collimation effect in a wide angle range and with a large bandwidth. Our works presented in this review show that PhCs have a strong power of controlling propagation of light at micrometer/ nanometer scale and possess a great potential of applications in integrated photonic circuits.
文摘In this paper, the photonic band gap （PBG） properties of two dimensional （2D） square lattice photonic crystal structures composed of rectangular cells were studied. The effect of refractive index, rectangles length and the ratio of width to length of the rectangles on the PBG properties of the structure with different configura- tions was investigated. It is found that the density of gaps in both modes （transverse electric （TE） and transverse magnetic （TM）） is high for structure composed of rectangular dielectric rods in gaps is very low for structure pores in dielectric material. air, while the density of the composed of rectangular air
文摘In this paper, we presented switching dynamic investigations on an InP photonic-crystal （PhC） nanocavity structure using homodyne pump-probe measurements. The measurements were compared with simulations based on temporal nonlinear coupled mode theory and carrier rate equations for the dynamics of the carrier density governing the cavity properties. The results provide insight into the nonlinear optical processes that govern the dynamics of nanocavities.
基金The Natural Science Foundation of Fujian Province of China(No.2011J01017)the Research Project of Science and Technology of Fujian Education Office of China(No.JB11149)the Nursery Project of Science and Technology of Minjiang University(No.YKY1103)
文摘In this work, the characteristics of the photonic crystal tunneling injection quantum dot vertical cavity surface emitting lasers（Ph C-TIQD-VCSEL） are studied through analyzing a modified modulation transfer function. The function is based on the rate equations describing the carrier dynamics at different energy levels of dot and injector well. Although the frequency modulation response component associated with carrier dynamics in wetting layer（WL） and at excited state（ES） levels of dots limits the total bandwidth in conventional QD-VCSEL, our study shows that it can be compensated for by electron tunneling from the injector well into the dot in TIQD structure. Carrier back tunneling time is one of the most important parameters, and by increment of that, the bias current dependence of the total bandwidth will be insignificant. It is proved that at high bias current, the limitation of the WL-ES level plays an important role in reducing the total bandwidth and results in rollovers on 3-d B bandwidth-I curves. In such a way, for smaller air hole diameter of photonic crystal, the effect of this reduction is stronger.
