CN103412304A - Matter wave correlated image generation method and device thereof - Google Patents

Abstract

The invention relates to a method and a device for generating matter-wave correlation imaging. The matter-wave correlation imaging method includes the following steps: generating a partially coherent matter wave; projecting the partially coherent matter wave onto an atomic grating, and forming a periodically distributed matter wave density image on a detection surface with an integer multiple of Talbot distance; Select the signal matter wave and the reference matter wave projecting the object to be measured from the density image; project the signal matter wave onto the object; carry out bucket measurement on the signal matter wave after projecting the object and perform spatial correlation with the reference matter wave to obtain image of the object. The present invention uses cold atomic matter waves instead of light waves as the wave source for correlation imaging, which has shorter wavelengths and higher imaging resolution; the present invention generates signal matter waves and reference matter waves through atomic gratings, avoiding matter wave splitting The destruction of the matter wave quantum correlation by the device and the asymmetric transmission process has the characteristics of simple device, fast imaging speed and large number of images.

Description

Method and device for generating matter-wave correlation imaging

technical field

The invention relates to a material wave correlation imaging method and a device thereof. the

technical background

Correlative imaging (ghost imaging) is a novel imaging mechanism. It utilizes the partial coherence or quantum entanglement characteristics of the light source to realize the acquisition of the diffraction image of the object with nanometer resolution in the optical path without the object. The principle is shown in Figure 1. A continuous partially coherent light beam generated by the pseudothermal light source 11 is split into signal light and reference light by a beam splitter 12 . The signal light illuminates a preselected hollow object 14 . The barrel detector 15 is arranged behind the hollow object 14, and the barrel detector 15 is composed of an avalanche photodiode and is arranged at a fixed position. The reference light is captured by the area detector 13 . The measurement results of the barrel detector 15 and the surface detector 13 are sent to a data processor 16 . After being processed by the data processor 16, the second-order correlation function of the light beam at the barrel detector 15 and the surface detector 13 can be obtained. Imaging results may be obtained from the output of the data processor. Correlative imaging is widely used in distributed image processing, distributed sensing, and communication. the

With the rise of cold atom optics in recent years, and the realization of the Hanbury-Brown-Twiss (HBT) effect in the field of matter waves (see academic papers Schellekens, M. et al. Hanbury Brown Twiss Effect for Ultracold Quantum Gases SCIENCE2005310, 648-651), the feasibility of matter-wave correlation imaging has received more and more attention. The above Hanbury-Brown-Twiss scheme can be used for the transmission of single-bit quantum information in matter waves, but it cannot be directly used in the field of imaging with multi-bit quantum information. Correlation imaging between matter particles and matter particles has important application value in quantum communication and quantum computing. Compared with light waves, matter waves have shorter wavelengths and higher imaging resolution. the

Correlation imaging requires the transmission of multi-bit quantum information. Beam splitter is an important device in correlative imaging system. The light beam generated by the light source is divided into two by the beam splitter, one of which is called signal light and the other is called reference light. The signal light path contains the object to be imaged, and the reference light path does not contain the object. Through the coincidence measurement of the two beams of light, the image of the object can be obtained on the reference light path. In the field of matter waves, the manufacture of matter wave beam splitting devices is complex and difficult to process, and the beam splitting efficiency is not high. This makes it very difficult to implement correlative imaging methods in the field of matter waves, which limits the application and promotion of correlative imaging technology. the

In the prior art, there is a correlation imaging method using a periodic grating instead of a beam splitter (see academic paper Li, H., Chen, Z., Xiong, J. & Zeng, G. Periodic diffraction correlation imaging without a beam-splitter .Opt.Express 201220, 2956-2966). This method has considerable advantages, but it still cannot be used as a matter-wave correlation imaging solution. The main reason is that this method is designed for pseudothermal light sources. The matter waves of will produce additional phases. This additional phase will affect the accuracy of imaging results, thus limiting the application and promotion of this method in the field of matter waves. the

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art, and provide a correlative imaging method with simple steps, convenient implementation and wide application to matter waves. the

Another object of the present invention is to provide an imaging device that can reduce costs and realize matter wave imaging. the

The technical solution adopted by the present invention to solve the above-mentioned technical problems is a matter-wave correlation imaging method, the steps of which are:

(1) Generate partially coherent matter waves;

(2) Projecting the part of the coherent matter wave onto the atomic grating to generate a signal matter wave and a reference matter wave;

(3) Projecting the signal matter wave onto a hollowed-out object placed on the detection plane in advance;

(4) Carrying out barrel measurement on the signal matter wave projected on the object and performing spatial correlation with the reference matter wave to obtain an image of the object. the

(5) Perform multiple correlation measurements on the object, and perform signal processing on the correlated data. the

In a preferred technical solution of the matter-wave correlation imaging method of the present invention, the partially coherent matter wave is a monoenergetic cold atomic beam. the

In a preferred technical solution of the matter-wave correlation imaging method of the present invention, the atomic grating is formed by a laser standing wave field that is far out of tune with the atomic resonance energy level. the

In a preferred technical solution of the matter-wave correlation imaging method of the present invention, the matter wave passes through the atomic grating to generate a diffracted matter wave with a periodic structure on a detection plane that is an integer multiple of the Taber distance from the atomic grating. the

In a preferred technical solution of the matter-wave correlation imaging method of the present invention, the matter waves in any two period units of the diffracted matter waves are respectively used as signal matter waves and reference matter waves projected on the object to be measured. the

A preferred technical solution of the matter-wave correlation imaging method of the present invention, when performing correlation measurement on the object, the correlation data of the signal matter wave after projecting the object and the reference matter wave

Γ=< _∫object t(x ₁ )D(x ₁ )dx ₁ D(x ₂ )>= _∫object <t(x ₁ )D(x ₁ )D(x ₂ )>dx ₁

＝ _∫Object t(x ₁ )<D(x ₁ )D(x ₂ )>dx ₁

= _∫object t(x ₁ )G ⁽²⁾ (x ₁ , x ₂ )dx ₁

Where t(x) is the image transmission function of the hollow object, D(x) is the atomic density of the diffracted matter wave, ∫ _object t(x ₁ )D(x ₁ )dx ₁ is the The barrel measurement data, G ⁽²⁾ (x ₁ , x ₂ ) is the second-order correlation function of the diffracted matter wave.

A preferred technical solution of the matter-wave correlation imaging method of the present invention, when performing correlation measurement on the object, the second-order correlation characteristics of the matter wave

G ⁽²⁾ (x ₁ , x ₂ )＝1+|G ⁽¹⁾ (x ₁ , x ₂ )| ²

Among them, G ⁽¹⁾ (x ₁ , x ₂ ) is the first-order correlation function of the matter wave.

The technical solution adopted by the present invention to solve the above technical problems also provides a matter-wave correlation imaging device, the structural features of which include:

(1) cold radical generator, which generates partially coherent matter waves;

(2) Atomic grating, the atomic grating is formed by a laser standing wave field far out of tune with the atomic resonance energy level, which diffracts the partially coherent matter wave and forms a matter wave distribution with a periodic structure;

(3) barrel detector, the barrel detector detects the signal matter wave after projecting the object to be measured;

(4) surface detector, described surface detector is made of microchannel plate, is used for detecting reference matter wave;

(5) a data processor, the data processor receives the signals of the barrel detector and the surface detector, and correlates the two to obtain the image of the object. the

In a preferred technical solution of the matter-wave correlation imaging device of the present invention, the barrel detector and the surface detector are respectively placed on the periodic structural unit formed by the diffraction of the partially coherent matter beam. the

A preferred technical solution of the matter-wave correlation imaging device of the present invention is to correlate and measure the signal matter wave after projecting the object and the reference matter wave signal

Γ=< _∫object t(x ₁ )D(x ₁ )dx ₁ D(x ₂ )>= _∫object <t(x ₁ )D(x ₁ )D(x ₂ )>dx ₁

＝ _∫Object t(x ₁ )<D(x ₁ )D(x ₂ )>dx ₁

= _∫object t(x ₁ )G ⁽²⁾ (x ₁ , x ₂ )dx ₁

Wherein t(x) is the image transmission function of the hollow object, D(x) is the atomic density of the diffracted matter wave, ∫ _t (x ₁ )D(x ₁ )dx ₁ is the The measured data, G ⁽²⁾ (x ₁ , x ₂ ) is the second-order correlation function of the diffracted matter wave.

A preferred technical solution of the matter-wave correlation imaging method of the present invention, when performing correlation measurement on the object, the second-order correlation characteristics of the matter wave

G ⁽²⁾ (x ₁ , x ₂ )＝1+|G ⁽¹⁾ (x ₁ , x ₂ )| ²

Among them, G ⁽¹⁾ (x ₁ , x ₂ ) is the first-order correlation function of the matter wave.

Compared with the prior art, the present invention has the following advantages: the correlative imaging method of the present invention uses cold atomic matter waves instead of light waves as the wave source of correlative imaging, and has the characteristics of shorter wavelength and higher imaging resolution; The correlative imaging device does not use the material wave splitter which is complicated and difficult to process, but uses the atomic grating formed by the standing wave field of the laser to diffract the incident material wave, and select the signal material wave and the reference material wave from the diffraction pattern, avoiding the The matter-wave beam splitter and the asymmetric transmission process destroy the matter-wave quantum correlation, which has the advantages of reasonable structural design, fewer components, convenient implementation, fast imaging speed, and large number of images. the

Description of drawings

FIG. 1 is a schematic structural diagram of an associated imaging system in the prior art. the

Fig. 2 is a schematic structural diagram of a matter-wave correlated imaging system according to an embodiment of the present invention. the

FIG. 3 is a schematic diagram of a material wave density image with a periodic structure generated by the atomic grating shown in FIG. 2 on the detection surface 23 . the

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings. The following examples are explanations of the present invention, and are better application forms of the present invention, but the present invention is not limited to the following examples. the

Please refer to FIG. 2 . FIG. 2 is a schematic structural diagram of a matter wave imaging device according to an embodiment of the present invention. The matter wave imaging system includes a cold atom group generator 21 , an atomic grating 22 , a detection plane 23 , a hollow object 231 , a barrel detector 232 , a plane detector 233 , and a data processor 24 . The cold atomic group generator 21 generates partially coherent matter waves; the atomic grating 22 is formed by a laser standing wave field far out of tune with the atomic resonance energy level, which diffracts the partially coherent matter waves and forms a periodic structure matter wave distribution; the hollow object 231 is an object to be imaged; the barrel detector 232 is used to detect the signal matter wave after projecting the object to be measured 231; the surface detector 233 is made of a microchannel plate for Detecting reference matter waves; the data processor 24 is used to receive the signals of the barrel detector 232 and the surface detector 233 , and correlate them to obtain an image of the object 231 . The data processor 24 is a computer. the

Below in conjunction with Fig. 2, describe in detail the main steps of the matter wave imaging method of the present invention:

(1) Set the corresponding parameters of the cold radical generator 21 to generate partially coherent matter waves. Then, the partially coherent matter wave is allowed to fall freely onto the atomic grating 22 under the action of gravity. the

(2) The atomic grating 22 diffracts the incident cold atomic matter waves to generate diffracted matter waves with a periodic structure. the

(3) Projecting the diffracted matter wave onto the detection plane 23 at a distance L from the atomic grating. the

(4) Selecting the two periodic units formed by the diffracted matter wave on the detection plane 23 as the signal matter wave and the reference matter wave projecting the object to be measured;

(5) Projecting the signal matter wave onto a hollow object 231 placed on the detection plane in advance.

(6) The probe detector 232 measures the signal matter wave after the object is projected, and the measurement data is input into the data processor 24 . the

(7) The surface detector 233 measures the reference matter wave, and the measurement data is input into the data processor 24 . the

(8) The data processor 24 performs associated processing on the measurement data of the barrel detector 232 and the surface detector 233, that is, the barrel detector 232 and the surface detector 233 perform associated measurement on the object 231 to be imaged. , the data associated and measured by the data processor 24 is

Γ=< _∫object t(x ₁ )D(x ₁ )dx ₁ D(x ₂ )>= _∫object <t(x ₁ )D(x ₁ )D(x ₂ )>dx ₁

＝ _∫Object t(x ₁ )<D(x ₁ )D(x ₂ )>dx ₁

= _∫object t(x ₁ )G ⁽²⁾ (x ₁ , x ₂ )dx ₁

Wherein t(x) is the image transmission function of the hollow object, D(x) is the atomic density of the diffracted matter wave, ∫t(x ₁ )D(x ₁ )dx ₁ is the The measured data, G ⁽²⁾ (x ₁ , x ₂ ) is the second-order correlation function of the diffracted matter wave.

For partially coherent matter waves, G ⁽²⁾ (x ₁ , x2 ₎ ＝1+|G ⁽¹⁾ (x ₁ , x ₂ )| ² , where G ⁽¹⁾ (x ₁ , x ₂ ) is the first-order correlation function.

FIG. 3 is a schematic diagram of the density distribution of diffracted matter waves on the detection plane 23 according to an embodiment of the present invention. The square structure represents the periodic unit formed after the partially coherent matter wave is diffracted by the atomic grating. The shaded structure 31 represents the signal matter wave projection area, and the non-shaded structure 32 represents the reference matter wave projection area. This embodiment realizes matter-wave correlation imaging, and has the characteristics of reasonable structural design, fewer components, and convenient use. the

Claims (11)

1. A matter-wave correlation imaging method, characterized in that, comprising the steps of: (1) Generate partially coherent matter waves; (2) Projecting the part of the coherent matter wave onto the atomic grating to generate a signal matter wave and a reference matter wave; (3) Projecting the signal matter wave onto a hollowed-out object placed on the detection plane in advance; (4) Carrying out barrel measurement on the signal matter wave projected on the object and performing spatial correlation with the reference matter wave to obtain an image of the object. the (5) Perform multiple correlation measurements on the object, and perform signal processing on the correlated data. the 2. The matter-wave correlated imaging method according to claim 1, characterized in that: the partially coherent matter wave is a monoenergetic cold atomic beam. the 3. The matter-wave correlation imaging method according to claim 1, characterized in that: the atomic grating is formed by a laser standing wave field that is far out of tune with the atomic resonance energy level. the 4. The matter-wave correlation imaging method according to claim 1, characterized in that: the matter wave passes through the atomic grating, and generates a diffracted matter wave with a periodic structure on the detection plane that is an integer multiple of the Taber distance from the atomic grating. 5. The matter-wave correlated imaging method according to claim 4, characterized in that: the matter waves in any two periodic units of the diffracted matter waves are respectively used as signal matter waves and reference matter waves projected on the object to be measured. the 6. The matter-wave correlation imaging method according to claim 5, characterized in that: when performing correlation measurement on the object, the associated data of the signal matter wave and the reference matter wave after projecting the object Γ=< _∫object t(x ₁ )D(x ₁ )dx ₁ D(x ₂ )>= _∫object <t(x ₁ )D(x ₁ )D(x ₂ )>dx ₁ ＝ _∫Object t(x ₁ )<D(x ₁ )D(x ₂ )>dx ₁ = _∫object t(x ₁ )G ⁽²⁾ (x ₁ , x ₂ )dx ₁ Where t(x) is the image transmission function of the hollow object, D(x) is the atomic density of the diffracted matter wave, ∫ _object t(x ₁ )D(x ₁ )dx ₁ is the signal matter wave The barrel measurement data, G ⁽²⁾ (x ₁ , x ₂ ) is the second-order correlation function of the diffracted matter wave. 7. The matter-wave correlation imaging method according to claim 6, when performing correlation measurement on the object, the second-order correlation characteristic of the matter wave G ⁽²⁾ (x ₁ , x ₂ )＝1+|G ⁽¹⁾ (x ₁ , x ₂ )| ² Among them, G ⁽¹⁾ (x ₁ , x ₂ ) is the first-order correlation function of the matter wave. 8. A matter-wave correlation imaging device, characterized in that: comprising (1) cold radical generator, which generates partially coherent matter waves; (2) atomic grating, the atomic grating is formed by a laser standing wave field far out of tune with the atomic resonance energy level, which diffracts the partially coherent matter wave and forms a matter wave distribution with a periodic structure; (3) barrel detector, the barrel detector detects the signal matter wave after projecting the object to be measured; (4) surface detector, described surface detector is made of microchannel plate, is used for detecting reference matter wave; (5) a data processor, the data processor receives the signals of the barrel detector and the surface detector, and correlates the two to obtain the image of the object. the 9 . The matter-wave correlated imaging device according to claim 8 , wherein the bucket detector and the surface detector are respectively placed on the periodic structure unit formed by the diffraction of the partially coherent matter beam. the 10. The matter-wave correlation imaging device according to claim 8, wherein the data of correlating measurement of the signal matter wave and the reference matter wave signal after projecting the object Γ=< _∫object t(x ₁ )D(x ₁ )dx ₁ D(x ₂ )>= _∫object <t(x ₁ )D(x ₁ )D(x ₂ )>dx ₁ ＝ _∫Object t(x ₁ )<D(x ₁ )D(x ₂ )>dx ₁ =∫ _object t(x ₁ )G ⁽²⁾ (x ₁ , x ₂ )dx ₁ Wherein t(x) is the image transmission function of the hollow object, D(x) is the atomic density of the diffracted matter wave, ∫t(x ₁ )D(x ₁ )dx ₁ is the The measured data, G ⁽²⁾ (x ₁ , x ₂ ) is the second-order correlation function of the diffracted matter wave. 11. The matter-wave correlation imaging method according to claim 10, characterized in that, when performing correlation measurement on the object, the second-order correlation characteristic of the matter wave G ⁽²⁾ (x ₁ , x ₂ )＝1+|G ⁽¹⁾ (x ₁ , x ₂ )| ² Among them, G ⁽¹⁾ (x ₁ , x ₂ ) is the first-order correlation function of the matter wave.

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