共查询到20条相似文献,搜索用时 46 毫秒
1.
We have fabricated tapered photonic crystal fibers using a fusion splicer and experimentally observed the near-field mode distribution and the beam divergence of it. We have also compared characteristics of the tapered photonic crystal fiber with those of a tapered standard single-mode fiber. Unlike a tapered standard single-mode fiber, the mode field profile of a tapered photonic crystal fiber shows a good confinement of its field within the core region. The numerical apertures of tapered photonic crystal fibers are increased as the diameter of the fiber is decreased. 相似文献
2.
We have fabricated tapered photonic crystal fibers using a fusion splicer and experimentally observed the near-field mode distribution and the beam divergence of it. We have also compared characteristics of the tapered photonic crystal fiber with those of a tapered standard single-mode fiber. Unlike a tapered standard single-mode fiber, the mode field profile of a tapered photonic crystal fiber shows a good confinement of its field within the core region. The numerical apertures of tapered photonic crystal fibers are increased as the diameter of the fiber is decreased. 相似文献
3.
Dellinger J Bernier D Cluzel B Le Roux X Lupu A de Fornel F Cassan E 《Optics letters》2011,36(7):1074-1076
The optical near-field technique is applied to provide a direct experimental observation of the refracted beam propagation inside a photonic crystal structure displaying a superprism effect. The obtained results show a 35° light beam angle deviation for a wavelength variation from 1500 to 1600 nm. The experimentally determined beam divergence is in good agreement with modeling predictions and previously performed transmittance experiments. A marked self-collimation propagation over a broad 20 nm wide spectral range centered at λ=1550 nm is experimentally demonstrated. The developed technique opens promising perspectives for the invisibility cloaking structures investigation. 相似文献
4.
研究了光子晶体波导对垂直腔面发射激光器(VCSEL)光束远场形貌的调控.采用三层对称平板波导模型分析了影响光子晶体VCSEL(PC-VCSEL)远场发散角的参数.研究表明,PC-VCSEL中光子晶体的填充比(空气孔直径和光子晶体周期的比值)以及空气孔的刻蚀深度控制了光束的发散角,低填充比和浅刻蚀的PC-VCSEL有利于获得低发散角的光束.设计并制作了两种不同结构参数的PC-VCSEL,这两种器件中光子晶体的填充比和空气孔的刻蚀深度不同.实验结果表明,低填充比和浅刻蚀的PC-VCSEL的发散角更低,与理论分析符合得很好. 相似文献
5.
H. Kurt 《Applied physics. B, Lasers and optics》2009,95(2):341-344
To obtain highly directional light output from photonic crystal waveguides (PCWs), the emission characteristics of the narrow-width
waveguide structures are investigated by tailoring the geometry of the exit sides. The local structural deformations in the
form of air hole removal from the triangular-lattice photonic crystal (PC) show the effectiveness of the previously proposed
approach that was implemented by us for another type of PC. The spatial broadening of the beam is greatly suppressed. With
the modified waveguide exits, highly directional emissions with small side lobes are achieved. The frequency dependency of
the directional emissions is evaluated. We show that the divergence angles of the beams depend linearly on the wavelength
for a regular type of PCW but the modified PCW exits have local minima with respect to wavelength in terms of the divergence
angle. The present work may prove to be helpful in the design of couplers and edge-emitting lasers and in the implementation
of free-space optical communications. 相似文献
6.
Hung-Pin D. Yang I-Chen Hsu Gray Lin Nikolai A. Maleev Hao-Chung Kuo 《Optics Communications》2007,274(1):94-99
An InGaAs sub-monolayer (SML) quantum dot photonic crystal vertical-cavity surface-emitting laser (QD PhC-VCSEL) for fiber-optic applications is first time demonstrated. The active region of the device contains 3 InGaAs SML QD layers. Each of the InGaAs SML QD layer is formed by alternate deposition of InAs (<1 ML) and GaAs. Single fundamental mode CW output power of 3.8 mW at 28 mA has been achieved in the 990 nm range, with a threshold current of 0.9 mA. Side-mode suppression ratio (SMSR) larger than 35 dB has been demonstrated over entire current operation range. The beam profile study of the PhC-VCSEL indicates that the laser beam is well confined by the photonic crystal structure of the device. The divergence angle of the devices remains almost unchanged with increasing current. 相似文献
7.
This paper reports that, based on the electromagnetic
scattering theory of the multipole method, a high-quality hollow beam is
produced through a selectively liquid-filled photonic crystal fibre.
Instead of a doughnut shape, a typical hollow beam is produced by
other methods; the mode-field images of the hollow-beam photonic
crystal fibre satisfy sixth-order rotation symmetry, according to
the symmetry of the photonic crystal fibre (PCF) structure. A dark
spot size of the liquid-filled photonic crystal fibre-generated
hollow beam can be tuned by inserting liquid into the cladding region
and varying the photonic crystal fibre structure parameters. The
liquid-filled PCF makes a convenient and flexible tool for the
guiding and trapping of atoms and the creation of all-fibre optical
tweezers. 相似文献
8.
We design a one-dimensional compound photonic crystal constituted of a periodic arrangement of electromagnetic-induced transparency atomic vapor. It is shown that, when a stochastic electromagnetic beam propagates through the compound photonic crystal, the spectral degrees of polarization and cross polarization of the beam can be modulated by changing the parameters of the supercells of the compound photonic crystal. 相似文献
9.
Lu Z Shi S Murakowski JA Schneider GJ Schuetz CA Prather DW 《Physical review letters》2006,96(17):173902
We present our experimental demonstration of self-collimation inside a three-dimensional (3D) simple cubic photonic crystal at microwave frequencies. The photonic crystal was designed with unique dispersion property and fabricated by a high precision computer-controlled machine. The self-collimation modes were excited by a grounded waveguide feeding and detected by a scanning monopole. Self-collimation of electromagnetic waves in the 3D photonic crystal was demonstrated by measuring the 3D field distribution, which was shown as a narrow collimated beam inside the 3D photonic crystal but a diverged beam in the absence of the photonic crystal. 相似文献
10.
Transverse beam dynamics in a nonlinear photonic crystal fiber is studied numerically. The field decomposition in terms of Laguerre-Gaussian functions is used to simulate the propagation of a beam along the fiber. Symmetry breakdown due to the competition of transverse modes is demonstrated. Both the few-mode photonic crystal fiber and the endlessly single-mode photonic-crystal fiber are considered. In the photonic crystal fiber with broad gain region, the resulting beam structure is shown to depend strongly upon the initial conditions. 相似文献
11.
12.
This paper describes results of studies on photoluminescence from blue-emitting GaN LED wafers coated with a layer of synthetic
opal photonic crystals. Commercial LED wafer material was used and samples were coated with thin films consisting of several
layers of stacked spherical polystyrene balls. Various optical measurements were performed on these samples while they were
excited with a 405 nm laser beam. Diffraction pattern due to the photonic crystal structure, showing the underlying six-fold
symmetry, was recorded. The spectrum and angle-resolved intensity of photoluminescence were measured to understand the coupling
of LED light with the grown photonic crystal structure on top of the wafer. 相似文献
13.
Polarization beam splitters based on a two-dimensional photonic crystal of negative refraction 总被引:1,自引:0,他引:1
A two-dimensional metallo-dielectric photonic crystal of negative refraction was designed for the application of polarization beam splitters. To match the refractive index of air, the effective refractive index of the designed photonic crystal is -1 for TE polarization and +1 for TM polarization. Two types of polarization beam splitter are presented. 相似文献
14.
Aaron F. Matthews 《Optics Communications》2009,282(9):1789-1271
I studied experimentally beam self-collimation and splitting in two-dimensional microwave photonic crystals. Using a microwave photonic crystal fabricated from alumina rods, I present an experimental proof of principle for an earlier theoretical proposal [A.F. Matthews, S.K. Morrison, Yu.S. Kivshar, Opt. Commun. 279 (2007) 313] of a photonic crystal beam splitter based on the self-collimation effect. 相似文献
15.
16.
Berrier A Mulot M Swillo M Qiu M Thylén L Talneau A Anand S 《Physical review letters》2004,93(7):073902
We report on the first experimental evidence of negative refraction at telecommunication wavelengths by a two-dimensional photonic crystal field. Samples were fabricated by chemically assisted ion beam etching in the InP-based low-index constrast system. Experiments of beam imaging and light collection show light focusing by the photonic crystal field. Finite-difference time-domain simulations confirm that the observed focusing is due to negative refraction in the photonic crystal area. 相似文献
17.
基于硅纳米线波导的两级光子晶体缩束器 总被引:1,自引:0,他引:1
鉴于在微观领域光波的缩束对实现光电集成的重要意义,提出了基于硅纳米线波导的两级光子晶体缩束器。其中一级压缩基于W5型和W1型光子晶体波导间的高效耦合。二级压缩则由宽为0.1μm,长为3.06μm的纳米线波导和W1型光子晶体波导构成,通过二者的高效耦合实现光束压缩。当W1型光子晶体波导和纳米线波导间介质柱的半径为0.04μm时,对于1550nm波长的电磁波,缩束器的通光效率可达93.4%,压缩比为16.08,出射光束半峰全宽仅为0.148μm。 相似文献
18.
《Photonics and Nanostructures》2008,6(2):134-141
Waveguide circuits in three-dimensional photonic crystals with complete photonic band gaps are simulated with finite difference time domain (FDTD) simulations, and compared with measurements on microwave scale photonic crystals. The transmission through waveguide bends critically depends on the photonic crystal architecture in the bend region. We have found experimentally and theoretically, a new waveguide bend configuration consisting of overlapping rods in the bend region, that performs better than the simple waveguide bend of terminated rods, especially in the higher frequency portion of the band. Efficient beam splitters with this junction geometry are also simulated. 相似文献
19.
In this paper, using the plane-wave expansion and finite difference time-domain methods, the photons behavior in the photonic crystal is investigated. Theoretically, when a polarized wave is incident from the background medium to the photonic crystal, the beam propagation directions in the photonic crystal determined by two methods are approximately same. But in this paper, the results exhibit that there is an additional direction obtained by the finite difference time-domain method compared with the plane-wave expansion. Considering basic physical mechanism of the photon behavior, the present work circumvents the electromagnetic field distribution in the photonic crystal at a degenerate state, which can reasonably explain the phenomenon. Finally, it shows that a photonic crystal can be properly designed to achieve double refraction simultaneously at one frequency, which can also offer new thoughts and foundation for the novel beam splitter that applied to many optical systems. 相似文献
20.
Yongjin Wang Yoshiaki Kanamori Hongbo Zhu Kazuhiro Hane 《Photonics and Nanostructures》2012,10(1):146-152
We present here the fabrication and characterization of single layer silicon photonic crystal mirror on a silicon-on-insulator wafer. By a combination of electron beam lithography, fast atom beam etching with deep reactive ion etching, silicon photonic crystal slabs are achieved on 260 nm freestanding silicon membrane and sandwiched with air on the top and bottom. Their high refractive index contrasts enable photonic crystal slabs function as dielectric mirrors for externally incident light. The optical performances of fabricated photonic crystal slabs can be tuned by varying the width of separation grooves or the air-hole size, which represents a significant advantage of offering various approaches for optical response control. 相似文献