排序方式: 共有198条查询结果,搜索用时 93 毫秒
71.
Gishamol Mathew Anju Babu Jesly Jacob Vincent Mathew 《Superlattices and Microstructures》2008,44(2):203-207
This paper discusses the magneto-optic phase shift in garnet/semiconductor-on-insulator plasmonic waveguides. We consider two structures: (1) Y IG/Si/SiO2 and (2) Y IG/GaInAsP/AlInAs-oxide. A dispersion relation for the plasmon propagation has been derived and the nonreciprocal phase shift of the fundamental TM mode has been determined at wavelengths of 1.55 μm, 1.5 μm and 1.3 μm. 相似文献
72.
A. Amo D. Ballarini D. Sanvitto E. Kozhemyakina L. Via M.S. Skolnick J.S. Roberts 《Superlattices and Microstructures》2008,43(5-6):449
We present a time resolved experiment in which we dynamically tailor the occupation and temperature of a photogenerated exciton distribution in QWs by excitation with two delayed picosecond pulses. The modification of the excitonic distribution results in ultrafast changes in the PL dynamics. Our experimental results are well accounted by a quasiequilibrium thermodynamical model, which includes the occupation and momentum distribution of the excitons. We use this model and the two-pulse experimental technique to study the polariton dynamics in InGaAs-based microcavities in the strong coupling regime. In particular, we demonstrate that resonantly injected upper polaritons mainly relax to the lower polariton branch via scattering to large momentum polariton states, producing the warming of the polariton reservoir. 相似文献
73.
D. Scalbert M. Vladimirova A. Brunetti S. Cronenberger M. Nawrocki J. Bloch A.V. Kavokin I.A. Shelykh R. Andr D. Solnyshkov G. Malpuech 《Superlattices and Microstructures》2008,43(5-6):417
Time-resolved Kerr (Faraday) rotation experiments allow for the observation of polariton spin beats in both InGaAs and CdMnTe quantum well (QW) microcavities. The existence of these beats is an unambiguous manifestation of the coherent energy exchange between exciton and photon components of polariton states created by a circularly polarized and spectrally wide femtosecond laser pulse. The polariton states are also shown to be split into a linearly polarized doublet. This splitting is responsible for the polarization transfer between linearly and circularly polarized states. In a highest-quality sample, the resulting spin dynamics could be detected. 相似文献
74.
In this paper, two kinds of modified surface plasmonic
waveguides formed by nanometric parallel lines are proposed. The
finite-difference frequency-domain method is used to study
propagation properties of the fundamental mode supported by these
surface plasmonic waveguide structures. Results show that the
transverse magnetic field of the fundamental mode is mainly
distributed in the face to face region formed by two rods. With the
same geometrical parameters and the same working wavelength of
632.8~nm, in the case of rods with a triangular cross-section, the
degree of localization of field is strong, i.e. the mode area is
small, but the fraction of the modal power in the metal increases,
so the effective index increases and the propagation length of the
mode decreases. With the same geometrical parameters, relative to
the case of a working wavelength of 632.8~nm, when working wavelength
is large, the mode area of transverse magnetic field distribution is
large, i.e. the degree of localization of field is weak, and the
interaction of field and silver is weak too, then the effective
index decreases, so the propagation length increases. The rounded
radii of rods have a great influence on the performance of the surface
plasmonic waveguides with rounded triangular cross-sections, but have
little influence on the performance of surface plasmonic waveguides
with rounded square cross-sections. Since the distribution of
transverse magnetic field, effective index, propagation length and
the mode area can be adjusted by the geometrical parameters, this
kind of modified surface plasmonic waveguide can be applied to the
field of photonic device integration and sensors. 相似文献
75.
76.
Performance of superconducting nanowire single-photon detector with the fan coupling antenna array 下载免费PDF全文
The performance of superconducting nanowire single-photon detector (SNSPD) involving niobium nitride with the fan coupling antenna array is analyzed. The SNSPD has a high detection efficiency and counting rate. Hydrogen silsesquioxane and niobium nitride are filled in the gold grating deposited on the substrate in which the fan coupling antenna arrays are embedded. By changing the position of the fan coupling antenna array, the maximum area of optical intensity is obtained and the photon collection efficiency is increased by 26.5 times. The detection efficiency of SNSPD is improved without changing the detection speed. These parameters are important for designing a practical single-photon detector, 相似文献
77.
Long-range surface plasmon polaritons with subwavelength mode expansion in an asymmetrical system 下载免费PDF全文
Long-range surface plasmon polariton (LRSPP) modes in an
asymmetrical system, in which the thin metal film is sandwiched
between a semi-infinite substrate and a high permittivity polymer
film with a finite thickness, are theoretically calculated and
analyzed. Due to the high permittivity of the polymer film, at
proper polymer film thicknesses, the index-matching condition of the
dielectrics at both sides of the metal can be satisfied for
supporting LRSPP modes, and the electromagnetic field above the
metal can be localized well. It is found that these LRSPP modes have
both long propagation lengths and subwavelength mode expansion above
the metal at the optimal polymer film thicknesses. Furthermore, the
requirements on the refractive index and the thickness of the
polymer film to support LRSPP modes at the optimal thicknesses are
found to be not critical. 相似文献
78.
This paper describes a multi-reflected mode based on a
narrow waveguide to enlarge the interferential area of surface
plasmon polaritons (SPPs). A reasonable thickness of metal film is
coated under the waveguide, the incident angle and the waveguide
thickness are optimized in order to effectively increase
interferential area. This is a key point for research into the
Goos--H\"anchen shift to optimize the waveguide thickness. Finally,
the SPP interferential field is simulated with the finite-difference
time-domain (FDTD) technique to prove the optimized results, and
indicates that not only is the interferential area enlarged, but
the high contrast is also maintained. Furthermore, the mode can
fabricate some specific interferential patterns by adding some
modulating techniques to the waveguide. So the mode has potential
application in the fabrication of sub-wavelength patterns. 相似文献
79.
Dengpan Wang Guangming Wang Tong Cai Kaiyue Liu Haipeng Li Ruiqi Mao Borui Wu 《Annalen der Physik》2020,532(6):2000008
Spoof surface plasmon polariton (SSPP) antennas are of particular importance in communication and radar systems. Currently available SSPP radiation devices are limited to low performance with high side-lobes because it is extremely challenging to accurately control the wave vector of SSPP and the inherent momentum mismatch between the SSPP and spatial waves. Inspired by the optical principle of reversibility, high-performance radiation control of SSPP is proposed to be achieved with transmissive phase gradient metasurface (TPGM). The TPGM, placed a meticulously optimized distance above the SSPP propagation structure, can provide an additional opposite wave vector to match the momentum between the SSPP and spatial waves. When the propagating SSPP transmits on the TPGM, it can be decoupled into the free space accurately and flexibly. Numerical results coincide well with the measurements, indicating that the radiation control of SSPP achieves high-performance and low side-lobe within 9 to 10.5 GHz with the measured radiation efficiency higher than 50%. The measured maximum efficiency appears at 9.8 GHz for 69%. Thanks to the flexible and accurate manipulation of the dispersion relation of SSPP provided by TPGM, the findings may open an avenue in achieving larger angle scanning antenna. 相似文献
80.
Alexander E. Minovich Angela E. Klein Dragomir N. Neshev Thomas Pertsch Yuri S. Kivshar Demetrios N. Christodoulides 《Laser \u0026amp; Photonics Reviews》2014,8(2):221-232
Airy beams represent an important class of non‐diffracting waves which can be realized on a flat surface. Being generated in the form of surface‐plasmon polaritons, such Airy plasmons demonstrate many remarkable properties: they do not diffract while propagating along parabolic trajectories, and they recover their shape after passing through obstacles. This paper reviews the basic physics of Airy plasmons in both paraxial and non‐paraxial cases, and describes the experimental methods for generation of Airy surface waves on metal surfaces, including a control of their trajectories, as well as the interference of Airy plasmons and hot‐spot generation. Many unusual properties of Airy plasmons can be utilized for useful applications, including plasmonic circuitry and surface tweezers. Picture: Observation of two colliding Airy plasmons. 相似文献