共查询到20条相似文献,搜索用时 31 毫秒
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The need for purely laboratory-based light pseudoscalar particles searches has been emphasized many times in the literature, since astrophysical bounds on these particles rely on several assumptions to calculate the flux produced in stellar plasmas. In this Letter we study the use of light from synchrotron accelerators as a source for a photon regeneration experiment also know as “light shining through a wall”. Such an experiment can significantly improve present limits on the pseudoscalar particle mass and the pseudoscalar–photon coupling constant obtained from laser experiments. This is possible even using a small number of powerful magnets (B∼10 T), due to the large incident photon flux. On the other hand, the use of a broadband incident photon-beam instead of infrared or optical lasers allows a significant improvement in the mass reach of the experiment (it is possible to test masses up to 0.01 eV without a drop in sensitivity). Large, but still feasible, configurations can explore in a quite model-independent way a large part of the parameter space examined by solar searches and HB stars in globular clusters. Additionally, the proposal may be useful for testing string motivated effective theories containing light and weakly interacting particles. 相似文献
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Vincent Tombelaine Erik Vater Benjamin Dietzek Jürgen Popp Hartmut Bartelt Raphaël Jamier 《Optics Communications》2011,284(7):1970-1974
Supercontinuum fiber light sources with their extremely wide wavelength spectrum can provide new options for achieving specific wavelength distributions in a very flexible way. Two concepts for the combination of such supercontinuum light sources with a spectrally dispersive optical system and an interactive filter for modulating the light spectrum are discussed. These concepts provide the possibility to achieve laser-like light sources with an almost arbitrary shape of the spectrum, great flexibility in interactive tuning of the spectral properties and covering wavelengths from UV to the infrared range. 相似文献
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A two-level medium, described by the Maxwell-Bloch system, is engraved by establishing a standing cavity wave with a linearly polarized electromagnetic field that drives the medium on both ends. A light pulse, polarized along the other direction, then scatters the medium and couples to the cavity standing wave by means of the population inversion density variations. We demonstrate that control of the applied amplitudes of the grating field allows one to stop the light pulse and to make it move backward (eventually to drive it freely). A simplified limit model of the Maxwell-Bloch system with variable boundary driving is obtained as a discrete nonlinear Schr?dinger equation with tunable external potential. It reproduces qualitatively the dynamics of the driven light pulse. 相似文献
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Following the recent work of Chandleret al on quasi probability distributions for spin-1/2 particles, we show that polarized light can be interpreted in terms of trivariate
probability distributions in two different ways by choosing the variates to correspond to (i) the co-ordinates on the Poincare
sphere, (ii) the components of the spin operator of the photon. In either case, it is shown that the Margenau-Hill procedure
leads to probability mass functions while the Wigner-Weyl approach leads to probability density functions and the well-known
Stokes parameters are also realised as appropriate averages with respect to these distribution functions. 相似文献
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Without need of another control light, this paper analyses in a time-dependent way a new scheme to achieve ultraslow propagation of the input probe field through a medium composed of two-level atoms where their upper level is split into two hyperfine sub-levels via some applied static field such as a DC magnetic or a DC electric field or whatever other static field.[第一段] 相似文献
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We show that fast and slow light results from multiple scatterings in a liquid crystal light valve, where nondegenerate two-wave mixing occurs in the Raman-Nath regime of optical diffraction. The large nonlinear response and dispersive characteristics of the liquid crystals allow us to obtain group velocities as slow as less than 0.2 mm/s, which is attractive for the realization of ultrahigh precision interferometers and metrology measurements. 相似文献
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A novel concept for an all-optical transistor is proposed and verified numerically. This concept relies on cross-phase modulation between a signal and a control pulse. Other than previous approaches, the interaction length is extended by temporally locking control and the signal pulse in an optical event horizon, enabling continuous modification of the central wavelength, energy, and duration of a signal pulse by an up to sevenfold weaker control pulse. Moreover, if the signal pulse is a soliton it may maintain its solitonic properties during the switching process. The proposed all-optical switching concept fulfills all criteria for a useful optical transistor in [Nat. Photon. 4, 3 (2010)], in particular, fan-out and cascadability, which have previously proven as the most difficult to meet. 相似文献
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Svetlana Lipnitskaya Karim Mynbaev Lidiya Nikulina Vladimir Kramnik Vladislav Bougrov Alexey Kovsh Maxim Odnoblyudov Alexey Romanov 《Optical Review》2014,21(5):655-658
A research has been carried out on the optimization of the shape of encapsulating cover to minimize optical losses in light-emitting modules fabricated with the “chip-on-board” (COB) technology. Optical properties of the components of a typical COB were taken into account including those of the substrate, light-emitting chips, encapsulating material and phosphor particles. Light losses were analyzed for various types of encapsulant surface structuring in an attempt to design an optical element with maximum light extraction efficiency. Calculations were complemented with experimental measurements. The results of the research showed that structuring the surface of the encapsulant can enhance light extraction by 10 to 15% for the material without phosphor particles and by 10 to 14% for the material with phosphor particles. 相似文献
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《Optik》2014,125(16):4505-4507
We present our experimental demonstration of controlling waveform of a signal pulse by using two beams of continuous wave (CW) generated by stimulated Brillouin scattering (SBS) in optical fibers with different frequencies. Waveform of the signal pulse is modulated in an “all-optical” way according to total input power. This method is only suitable for light pulse with nanosecond width. We provide a new method for controlling light with light. 相似文献
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关于探照灯照射的光斑速度 总被引:1,自引:1,他引:0
光速(真空中)是自然界物体运动或信息及能量传递的极限,如果不注意这个条件,一般地谈速度,那么,找寻超光速的现象并不是难事.有些教科书上时常以探照灯光斑移动的速度来阐述这种超光速现象,演算得到光斑移动的速度为v=hωcos2θ.本文指出,此结果是错的!对正确结果做的定量计算表明:光斑速度虽仍然能超光速,但正确结果的超光速条件远比错误结果的超光速复杂,而且物理含义也更加丰富. 相似文献
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By performing optical two-wave mixing in a liquid crystal light valve, we are able to slow down optical pulses to group velocities
as slow as a few tenths of mm/s, corresponding to a very large group index. We present experiment and model of the slow light
process occurring in liquid crystal light valves. The large group index corresponds to having a large sensitivity for phase
variations, a property that can be used to increase the sensitivity of Fourier transform interferometer. We show that when
a liquid crystal light valve is inserted in a Mach–Zehnder interferometer, the effect of frequency perturbations at the input
of the system is amplified by a factor related to the group delay. 相似文献
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James T. Wheeler 《General Relativity and Gravitation》1989,21(3):293-305
Normally, pure states of coherent light have equal uncertainties for pairs of conjugate variables. In recent years, however, it has become possible to produce and detect light in which fluctuations of one of the quadrature components are suppressed below the corresponding flutuations of a coherent state. Such radiation is said to be in a squeezed state. We explore the possibility that a strong gravitational field can produce a squeezed state of light. Such squeezing does in fact occur, and we derive an expression for the resulting uncertainties in a high frequency or long time limit. These results comprise a new, testable prediction of general relativity. 相似文献
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Terning J 《Physical review D: Particles and fields》1996,53(5):R2284-R2287
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Lossless light projection 总被引:1,自引:0,他引:1
A new technique for energy-preserving phase-only light projection is demonstrated. The phase-only encoding is based on an extension of the Zernike phase-contrast method into the domain of full-range [0; 2pi ] phase modulation, breaking the usual small-phase-angle limitation. Controlling the spatial average value of the input-phase pattern and choosing appropriate phase retardation at the phase-contrast filter yield pure-phase-based image formation. Experimental results demonstrate close to 90% energy efficiency. Output intensity levels with magnitudes more than 3.5times that of the input intensity level were measured in the brightest regions of the projected images. 相似文献
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