Double slit interferometer

Fig. 7.11 (a) Scheme of a double-slit interferometer. The atoms can move along two spatially separated paths from the source to the detector, (b) Atomic density profile, monitored with an 8 pm grating in the detector plane, as a function of the lateral displacement of the grating. The dashed line is the detector backgrormd. The line coimecting the experimental points is a guide to the eye. (Reprinted from Carnal and Mlynek 1991 with courtesy and permission of the American Physical Society.)... 

This chapter is organized as follows In Section 2, quantum states are briefly described. Section 3 presents aspects of standard quantum measurement model. Section 4 includes double-slit, Einstein-Podolsky-Rosen, and Tonomura s experiments. Section 5 illustrates calculations of quantum states for quantum measurements. In Section 6, atom interferometer experiment of Scully et al. is analyzed. A detailed discussion is presented in Section 7, emphasizing a physical perception of quantum mechanics. 

Fig. 14 Schematic drawings of interferometric arrangements (a) Mach-Zehnder configuration the sensing and the reference branch are combined after the interaction of the sample and a photodiode (D) that records the light intensity time-resolved, (b) Young interferometer. The sensing and the reference branch interfere in the far field. The interference pattern is recorded by a CCD. Either the end face of the waveguide structure approximates two point light sources or a double slit can be set in the beam path to generate the interference pattern. L interaction length, input power, Fou, output power...

Three apertures are used (i) a single slit 1.5 mm wide (ii) a double slit, each slit 1.5 mm wide, with the centres separated by 5.5 mm (iii) a third aperture being identical to the second with one of the slits covered with a low-pass Alter (edge at 21 cm ). The third aperture is used to have a different source not only spatially, but also spectrally. As the interferometer is only sensitive in one spatial dimension, the slits are arranged perpendicular to the projected scanning direction to increase the overall signal available. 

For a double slit source, the modulation due to the source being spatially resolved appears at lower frequencies, as expected, because the source is spatially bigger than the interferometric beam for any baseline length. In this particular case, this modulation due to the Stellar Interferometer almost reaches zero intensity, because we are interfering two almost identical sources and therefore destructive interference is achieved. The destructive interference is not complete due to the different optical elements in the system (i.e. transmissions of the optical elements, the spectral arm contains one extra mirror compared to the spatial arm). 

O. Carnal, J. Mlynek Young s double slit experiment with atoms a simple atom interferometer. Rhys. Rev. Lett. 66, 2689 (1991)... 

Quantum interferometers have been built to recreate the classic double-slit interference experiment, using single atoms instead of a light beam. 

A beam of slow atoms can be manipulated in many ways. This is performed within the field of atom optics [9.445-9.447]. An atomic beam can be bent or focused using laser fields. An atomic beam can also be reflected at an optical surface using the evanescent optical field from a laser beam reflected from the other side of the surface. The atom version of the Yoimg double-slit experiment has been performed, even with monochromatic thermal atoms, showing clearly the existence of matter waves [9.448]. Beam splitters for slow atomic beams can be optically achieved to build atomic interferometers based on de Broglie wave interference. The thermal de Broglie wavelength... 

We know of many types of optical interferometer (the simple double-slit Young interferometer, the Mach-Zehnder interferometer, the Fabry-Perot interferometer, the Talbot interferometer, etc.). A similar situation occurs in atom interferometry. Artificial laboratory devices exploit various types of structure for atom interferometry both material bodies (slits and gratings) and nonmaterial light structures. All these atom interferometers will be considered very briefly we refer readers for details to the book by Berman (1997) and reviews by Baudon et al. (1999), Kasevich (2002), and Chu (2002). 

A simple Young s double-slit atom interferometer was demonstrated by Carnal and Mlynek (1991). This experiment is schematically illustrated in Fig. 7.11. It used a... 

The simplest version of the atomic interferometer consists of two electrodes with the slits for passing the beam, separated with the variable gap L. For Lamb shift measurement corresponding interferometer is made of two two-electrode systems with longitudinal electric fields, mixing 2S and 2P-states. The systems were separated with a field-free gap of variable length L. This implies, that it is possible to write an exact expression for the probability W(L)e1,e2 of the yield I2P of 2P-atoms from the double system and determine, by processing the experimental dependence I2p(L), the Lamb shift value S. 

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