排序方式: 共有64条查询结果,搜索用时 15 毫秒
41.
Buczynski R Szoplik T Taghizadeh MR Veretennicoff IP Thienpont H 《Optics letters》2002,27(20):1818-1820
We present a demonstrator photonic system for mathematical morphology image processing. Optically interconnected arrays of differential pairs of optoelectronic transceivers realize morphological erosion and dilation in an 8x8 pixel size image. 相似文献
42.
We present a practical method for fast alignment of a ring laser cavity. With the aid of an auxiliary HeNe laser a closed path is formed in the cavity so that laser action can be quickly attained. 相似文献
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Maciej Antkowiak Rafał Kotyński Krassimir Panajotov Francis Berghmans Hugo Thienpont 《Optical and Quantum Electronics》2007,39(4-6):455-467
We study numerically the temporal and spatial dynamics of light in Bragg gratings in highly nonlinear photonic crystal fibre
for a CW input signal. Our numerical model is based on the plane wave mode solver and a set of nonlinear coupled-mode equations
which we solve using a variation of implicit fourth order Runge-Kutta method. We observe not only bistability of the intensity
versus transmitted and reflected light but also complex dynamics. We demonstrate that for values of input intensity above
the bistable region the steady state may undergo a supercritical Hopf bifurcation. For some ranges of the input intensity
we also observe a coexistence of two periodic attractors. The dynamics found, in particular the features in the bifurcation
diagram, strongly depend on the parameters of the fibre. Consequently, we suggest that by proper design of the photonic crystal
in the cladding we can adjust such nonlinear features of the Bragg gratings as the width of the bistable region, the intensity
at which the bifurcation occurs and also the characteristics of the dynamics at high values of input intensity. 相似文献
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K. Baert W. Meulebroeck H. Wouters P. Cosyns K. Nys H. Thienpont H. Terryn 《Journal of Raman spectroscopy : JRS》2011,42(9):1789-1795
Raman spectroscopy has been used to identify iron‐containing glasses. This nondestructive technique offers a fast method to obtain qualitative information about the presence of iron oxides in glass. The effect of the iron content in glass samples is reflected on the topology of the Raman spectra: A strong link between the ratio of the Q2/Q3 vibration units of the silica tetrahedral structure is seen. If matrix effects are taken into account, also (semi)quantitative results can be obtained from the calibration lines. The linear calibration is based on the normalized band intensity at 980 cm−1 (I980/I1090) and the iron oxide concentration for similar glasses. In amber and dark colored glasses, an extra peak in the spectrum indicates the presence of a FeS chromophore. Different series of glasses of various origins (ancient and modern/industrial glass) have been considered. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
47.
Tomasz Czyszanowski Robert Sarzała Maciej Dems Hugo Thienpont Krassimir Panajotov 《Optical and Quantum Electronics》2008,40(2-4):149-154
We present self-consistent modeling of InP-based 1300-nm AlInGaAs photonic-crystal vertical-cavity surface-emitting diode laser. We investigate the influence of photonic-crystal parameters on threshold characteristics. We show that a shallow photonic crystal can significantly deteriorate the VCSEL threshold current. The significant reduction of threshold current can be assured by the photonic-crystal etched through the whole top DBR mirror. 相似文献
48.
Maciej Antkowiak Rafał Kotyński Krassimir Panajotov Francis Berghmans Hugo Thienpont 《Optical and Quantum Electronics》2006,38(4-6):535-545
We analyze theoretically the coupling properties of Bragg gratings written in highly birefringent photonic crystal fibers
with doped core and show how they can be tuned by the parameters of a microstructured fiber. We apply the coupled mode theory
combined with a fully vectorial mode solver based on the plane-wave method. The results indicate large differences in interaction
with the grating for the two linearly polarized fundamental modes. We show fiber designs, which provide single-mode operation
with high birefringence and at the same time a high coupling efficiency of the grating. Such features can be used in fiber
sensors, fiber laser configurations or to introduce a polarization dependent feedback in a long external cavity system with
a semiconductor laser. 相似文献
49.
Rafal Kotynski Maciej Antkowiak Francis Berghmans Hugo Thienpont Krassimir Panajotov 《Optical and Quantum Electronics》2005,37(1-3):253-264
In this paper we are modeling the interplay of material and form birefringence in photonic crystal fibers. We introduce an efficient numerical method for the calculation of the modal structure. Our approach relies solving the fully vectorial wave equation for the transverse magnetic field and the respective propagation constants using a plane wave expansion. The method accounts for a simple form of material anisotropy. Our analysis is relevant to certain application areas, and in particular to fiber sensing, where material birefringence arises for instance due to transversally applied mechanical stress. We analyze the influence of material birefringence on the modal birefringence and the state of polarization of the fundamental mode. 相似文献
50.
Van Uytfanghe K Stöckl D Thienpont LM 《Rapid communications in mass spectrometry : RCM》2004,18(13):1539-1540