Double-slit Interference Experiment Research Articles

Young’s double-slit interference experiment with electrons

In this short Note we report a method for producing samples containing two nano-sized slits suitable for demonstrating to undergraduate and graduate students the double-slit electron interference experiment in a conventional transmission electron microscope.

Degree of polarization in Young's double-slit interference experiment formed by stochastic electromagnetic beams

We analyze the behavior of the degree of polarization in the interference field of Young's double-slit experiment. We analyze the degree of polarization in Young's double-slit interference experiment illuminated by stochastic electromagnetic beams. The distribution of the degree of polarization in the interference field for different correlation lengths and different slit widths is investigated. Furthermore, it is shown that the degree of polarization for a fixed observation point may take on values different from those it takes in the slits, depending not only on the value of the correlation length but also on the width of the slit.

Observation and Analysis of Phase-Locking in Parabolic Bow-Tie Laser Arrays

This paper presents experimental and theoretical results to show that in-phase coherent coupling occurs in high-power arrays of parabolic bow-tie lasers. Such devices require simple and inexpensive device fabrication, thus providing a cost-effective high-power laser for high-brightness operation at 980 nm. The maximum brightness achieved was 318 MWmiddotcm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> sr <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> at 20 times the threshold with far-field full-width at half-maximum less than 1.5 times the diffraction limit, measured without the use of external lenses under low-duty cycle (0.1%) pulsed operation. Results obtained from double-slit interference experiments show a clear distinction between phase-coherent arrays and corresponding arrays of independent emitters

Experimental study of the spectral anomalies in Young’s interference experiment

We report, the experimental result of a study, conducted to investigate the spectral anomalies in the region of superposition in the Young’s double-slit interference experiment. These results are in close agreement with the theoretical study by Pu et al. (J. Pu, C. Cai S. Nemoto, Opt. Express 12 (2004) 5131). The application of this study might be useful in realizing the information transmission in free space, in optical signal processing and optical computing.

Numerical simulation of the double slit interference with ultracold atoms

We present a numerical simulation of the double slit interference experiment realized by F. Shimizu, K. Shimizu and H. Takuma with ultracold atoms. We show how the Feynman path integral method enables the calculation of the time-dependent wave function. Because the evolution of the probability density of the wave packet just after it exits the slits raises the issue of interpreting the wave/particle dualism, we also simulate trajectories in the de Broglie–Bohm interpretation.

Dual Aharonov–Bohm Effect

The quantum dynamics of a magnetic monopole in the presence of a thin electric flux is investigated. We discuss the dual Aharonov–Bohm effect and we analyze this in the point of view of the duality transformation. We also study a double slit interference experiment for a magnetic monopole in the presence of an electric vector potential. We demonstrate the appearance of Berry's quantum phase in this dynamics. The scattering of a magnetic monopole by a thin electric flux tube is studied, the scattering amplitude and the phase shift are obtained.

Characteristics of a Saturated 18.9-nm Tabletop Laser Operating at 5-Hz Repetition Rate

We report the characteristics of a saturated high-repetition rate Ni-like Mo laser at 18.9 nm. This table-top soft X-ray laser was pumped at a 5-Hz repetition rate by 8-ps 1-J optical laser pulses impinging at grazing incidence into a precreated Mo plasma. The variation of the laser output intensity as a function of the grazing incidence angle of the main pump beam is reported. The maximum laser output intensity was observed for an angle of 20/spl deg/, at which we measured a small signal gain of 65 cm/sup -1/ and a gain-length product g/spl times/l>15. Spatial coherence measurements resulting from a Young's double-slit interference experiment show the equivalent incoherent source diameter is about 11 /spl mu/m. The peak spectral brightness is estimated to be of the order of 1/spl times/10/sup 24/ photons s/sup -1/ mm/sup -2/ mrad/sup -2/ within 0.01% spectral bandwidth. This type of practical, small scale, high-repetition soft X-ray laser is of interest for many applications.

Anomalous Behaviour of the Spectra in Young's Double-SlitInterference Experiments

It is shown that an anomaly of the spectrum takes place in theinterference field when Young's double-slit interference experiment isilluminated by spatially coherent polychromatic light. Specifically, drastic spectral changes (i.e. the spectral shifts exhibit a rapidtransition) occur in the vicinity of the dark fringes. The potentialapplications of this spectral anomaly are also considered.

Spectral anomalies in Young's double-slit interference experiment

We report a phenomenon of spectral anomalies in the interference field of Young's double-slit interference experiment. The potential applications of the spectral anomalies in the information encoding and information transmission in free space are also considered.

De Broglie wavelength of a non-local four-photon state.

Superposition is one of the most distinctive features of quantum theory and has been demonstrated in numerous single-particle interference experiments. Quantum entanglement, the coherent superposition of states in multi-particle systems, yields more complex phenomena. One important type of multi-particle experiment uses path-entangled number states, which exhibit pure higher-order interference and the potential for applications in metrology and imaging; these include quantum interferometry and spectroscopy with phase sensitivity at the Heisenberg limit, or quantum lithography beyond the classical diffraction limit. It has been generally understood that in optical implementations of such schemes, lower-order interference effects always decrease the overall performance at higher particle numbers. Such experiments have therefore been limited to two photons. Here we overcome this limitation, demonstrating a four-photon interferometer based on linear optics. We observe interference fringes with a periodicity of one-quarter of the single-photon wavelength, confirming the presence of a four-particle mode-entangled state. We anticipate that this scheme should be extendable to arbitrary photon numbers, holding promise for realizable applications with entanglement-enhanced performance.

Objectivity, retrocausation, and the experiment of Englert, Scully, and Walther

In a recent contribution to this journal [Am. J. Phys. 64, 1468–1475 (1996)] I wrongly asserted that retrocausation in the Englert, Scully, and Walther (ESW) experiment (a double-slit interference experiment with atoms) can occur only until the atom arrives at the screen. In their response, Englert, Scully, and Walther [preceding paper] point out my fallacy but give an incomplete analysis of its origin. In this paper I trace this fallacy to a deep-seated preconception about time and reality. I show that among the two possible realistic interpretations of standard quantum mechanics, the reality-of-states view and the reality-of-phenomena view, only the latter is viable. It follows that retrocausation is a necessary feature of any realistic account of the ESW experiment based on standard quantum mechanics. Finally I eludicate the sense in which the spatial properties of quantum systems are objective, and show that they are extrinsic rather than intrinsic.

Theory of phase-sensitive measurement of photon-assisted tunneling through a quantum dot

Recent double-slit interference experiments have demonstrated the possibility of probing the phase of the complex transmission coefficient of a quantum dot via the Aharonov-Bohm effect. We propose an extension of these experiments: an ac voltage imposed on the side gate with the concomitant photonic sidebands leads to additional structure both in the amplitude and in the phase of the Aharonov-Bohm signal. Observation of these effects would be a definitive proof of coherent absorption and reemission of photons from the ac source.

Quantum theory of double-slit interference: Role of the quantum phase

We discuss certain questions related to the phase of the quantum state of light by considering the double-slit interference experiment. In a quantum description of the situation one has to consider two phases, the mode phase and the quantum phase. By considering superpositions in different ways, it is shown that these two phases play rather distinct roles.

Phase evolution of the transmission coefficient in an Aharonov-Bohm ring with Fano resonance

Phase of the transmission coefficient for a mesoscopic loop with Fano resonance has been investigated by using the scattering matrix method, for a model of an Aharonov-Bohm ring with a double barrier coupled to a $t$-stub resonator in one arm. It is found that the phase varies rapidly by \ensuremath{\pi} on the shoulder of a resonance peak. In addition, it is found that there is a sudden phase jump by $\ensuremath{\pi}$ near the tail of a resonance peak. Each resonance peak is found to return to the same phase via two processes; in one process, the phase shift by $\ensuremath{\pi}$ occurs rather smoothly through the excitation of the $h/2e$ oscillation near the resonance peak, and in the other process, the same amount of phase shift occurs very abruptly across the zero transmission of the resonator. These phase behaviors show some resemblance to the ones found in the recent phase measurement of a quantum dot via double-slit interference experiment.

Two-photon double-slit interference experiment

We report a two-photon double-slit interference experiment. Two correlated photons, generated by spontaneous parametric downconversion and traveling in different directions, are made to pass through a double slit in such a way that the path of one photon can be identified with that of the other photon. No single-photon interference pattern is observed even if the path is not actually identified, but a spatial interference pattern appears in the joint detection counting rates of the photon pairs. It can easily be shown that these nonlocal phenomena cannot be exhibited by any kind of classical field.

Influence of a finite energy width on the hot electron double-slit interference experiment: A design of the emitter structure

The influence of electron energy width in the hot electron double-slit experiment is investigated quantitatively. The required condition on the Fermi level in the emitter and the slit-spacing is derived for the experiment. In order to achieve a coherent electron source, a single-barrier graded emitter structure is discussed and its characteristics are considered. For application to the hot electron double-slit experiment, the graded emitter diode is fabricated and the current–voltage relation is measured in a supplementary experiment.

Nonlocal momentum transfer inwelcher Wegmeasurements

A ``which-path'' (welcher Weg) measurement necessarily destroys the fringes in a double-slit interference experiment. We show that in all instances one may attribute this destruction to a disturbance of the particle's momentum by an amount equal to at least $\ensuremath{\pi}\ensuremath{\Elzxh}/2d$, where $d$ is the slit separation, in accordance with the uncertainty principle. However, this momentum transfer need not be local; that is, it need not act at either of the slits through which the particle passes. For well-known welcher Weg measurements such as Einstein's recoiling slit and Feynman's light microscope, the disturbance can be understood in terms of random classical momentum kicks that act locally. In some recent proposals, including that by Scully, Englert, and Walther [Nature (London) 351, 111 (1991)], the momentum transfer is of a peculiarly quantum, nonlocal nature. In this paper we introduce a formalism based on the Wigner function, as this describes both the local and nonlocal momentum transfer caused by any welcher Weg measurement. We show that for some examples, such as that of Scully, Englert, and Walther, there is no momentum disturbance at the slits even though the nonlocal momentum disturbance is sufficient to destroy the interference pattern. Finally, we discuss the experimental signatures of nonlocal versus local momentum transfer and demonstrate a strong similarity to the nonlocality of the Aharonov-Bohm effect.

Phase measurement in a quantum dot via a double-slit interference experiment

The transport properties of electronic devices are usually characterized on the basis of conductance measurements. Such measurements are adequate for devices in which transport occurs incoherently, but for very small devices—such as quantum dots1,2—the wave nature of the electrons plays an important role3. Because the phase of an electron's wavefunction changes as it passes through such a device, phase measurements are required to characterize the transport properties fully. Here we report the results of a double-slit interference experiment which permits the measurement of the phase-shift of an electron traversing a quantum dot. This is accomplished by inserting the quantum dot into one arm of an interferometer, thereby introducing a measurable phase shift between the arms. We find that the phase evolution within a resonance of the quantum dot can be accounted for qualitatively by a model that ignores the interactions between the electrons within the dot. Although these electrons must interact strongly, such interactions apparently have no observable effect on the phase. On the other hand, we also find that the phase behaviour is identical for all resonances, and that there is a sharp jump of the phase between successive resonance peaks. Adequate explanation of these features may require a model that includes interactions between electrons.

Electron holography shows its resolve

The wave nature of free electrons was first proposed by Louis de Broglie 70 years ago, and demonstrated three years later in famous experiments by George Thomson, Clinton Davisson and Lester Germer. Thomson observed circular fringes caused by the interference of electron waves scattered by a thin metal foil, whilst Davisson and Germer used nickel crystals to diffract the electrons. Seishi Kikuchi also obtained electron diffraction patterns using single-crystal mica films. Later double-slit interference experiments allowed this wave-particle duality to be observed directly: electrons are always detected individually, but when their distribution is integrated over time, an interference pattern characteristic of wave behaviour results, even when there is only one electron in the apparatus at any time (figure 1).

Low-intensity interference effects and hidden-variable theories

The double-slit interference experiment and other similar experiments in the low-intensity limit (that is, one photon in the apparatus at a time) are examined in the spirit of Bell’s work from the point of view of hidden-variable theories. It is found that there exists a class of hidden-variable theories which disagrees with quantum mechanics for a certain type of interference experiment. A manufactured conceptualization of this class, which is a particle view of interference, is described. An experiment, which appears to be feasible, is proposed to examine this disagreement.