CN105117774B - A kind of Magneto-Optical Trap method and device of laser cooling and trapping - Google Patents
A kind of Magneto-Optical Trap method and device of laser cooling and trapping Download PDFInfo
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Abstract
The present invention relates to laser cooling and trapping of the laser of two wavelength to stepped energy level alkali metal atom, the Magneto-Optical Trap method and apparatus that specially a kind of laser using atom storage wave band and two wavelength of optical communication wave band is cooled down and captured to atom.Comprise the following steps：Build the atom vacuum room containing printing opacity quartz window；Build the magnetic field part of Magneto-Optical Trap；Construction work is in the ground state and the light path part of the laser of middle excitation state of alkali metal atom；Construction work is in the middle excitation state and the light path part of the laser of more highly excited level of alkali metal atom；Build the probe portion for the atomic fluorescence being made up of charge-coupled device camera.Device of the present invention cooling and capture atom directly from room temperature hot atom vacuum room, available for the laser cooling and trapping to storing wave band and the alkali metal atom of optical communication wave band with atom；The application study of the cooling mechanism and quantum repeater based on four-wave mixing of atom is cooled down available for multi-photon.
Description
Technical field
The present invention relates to laser cooling and trapping of the laser of two wavelength to stepped energy level alkali metal atom, it is specially
A kind of laser for two wavelength that wave band and optical communication wave band are stored using atom carries out laser cooling and trapping to atom
Magneto-Optical Trap method and device.
Background technology
Since Hansch in 1975 and Schawlow proposes the suggestion that laser cools down neutral atom, and
The Willam Phillips of National Institute of Standards and Technology in the 1985 and Steven Chu (Steven of Stanford University
Chu) realize the laser cooling and trapping of neutral atom in an experiment first, greatly promoted Physics of Cold Atoms development and
Using such as atomic clock, optical tweezer, Bose-Einstein condensation, atom laser, high-resolution spectroscopy, it has also become modern physicses
One of most active research field in.The cold atoms obtained by laser-cooling technology, because there is the thing of other states
Matter（Such as the atom in normal temperature lower chamber）Unexistent advantage, development and practical application to physics have great importance.
In the late three decades, deep theory and experimental study work have been carried out in above-mentioned several respects in the world, and be progressively applied to
In social practice.In these great achievements obtained, the highly important effect of Magneto-Optical Trap technique functions.In quantum communication and
In quantum calculation, cold atom is to constitute one of basic scheme of quantum memory and transmitter, and Magneto-Optical Trap is to obtain cold atom
Most directly effective method.
The remote distribution of quantum state is the key technology of the quantum techniques such as following long-range quantum key distribution and quantum network,
In specific implementation, either free space transmission or the quantum channel of optical fiber transmission, can all cause transmission loss and dephasign
It is dry.Even for 1.5 micron optical fiber communication bands, its transmission loss is 0.2 dB/km, and number of photons is original after being transmitted through 100 km
1 % come, number of photons is changed into original 10 after 500 km-10.Using the quantum state emission source of 10 GHz ultrafast repetition rate as
Example, it is 0.1 GHz by the transfer rate of 100 km optical fiber, and for 500 km optical fiber, its transfer rate is 1 Hz, for 1000
Its efficiency of transmission of km optical fiber is 10-10 Hz.In classical communication, using amplifier or this transmission loss can be overcome,
And in quantum communication, due to the unclonable principle of quantum, direct amplifier is infeasible.It can only use and its complicated quantum
Repeater.
Tangling for relatively short distance is expanded to the quantum entanglement of long range by quantum repeater by entanglement transfer.With current
From the point of view of quantum repeater development, also in the laboratory research stage, most of be based on using atom assemblage and linear optics as base
The DLCZ agreements or the experimental demonstration of its improved protocol of plinth, but also be the demonstration of the via node of relatively short distance, what it was demonstrated
Transmission range is hundred meters of magnitudes.In these demonstrations, the photon wavelength of transmission is big to store wave band all in atom, and its wavelength is
700nm to 900nm, transmission loss is far longer than 1.1 ~ 1.7 microns of optical-fibre communications wave band, greatly limit transmission range, even
It is that the transmission of relatively short distance can not also be met.Foreign study personnel have invented stores wave band and optical-fibre communications wave band based on atom
In the quantum repeater of entangled photon pairs【Phys. Rev. Lett. 96,093604 (2006), patent No. US
20080258049A1】, transmission loss is greatly reduced, this is overcome difficult.In the invention, six beams cooling light and quadrupole
Rb atom coolings are obtained after a Cold atomic cloud, prepared by the conventional magneto-optic trap that field coil and anti-pumping light are constituted
To required quantum state, light field and magnetic field are then powered off, a branch of atom in addition is stored to the laser and a branch of fiber optic communication ripple of wave band
The laser of section, with specific low-angle acting in opposition to Cold atomic cloud, photon is collected in specific two angles as pump light,
Obtain association or even the two-photon pair tangled.But the laser of invention intervention is more, intervenes the direction of laser, collects the side of photon
Strict alignment is needed to waiting, is easily influenceed by arrangement of geometry vacuum pipe of atomic air chamber etc.；Each laser
Frequency and the time being switched on and off need strict control, add the complexity of control；The laser of communication band is not joined
With atom cooling, only opened in extremely short time window, utilization rate is not enough.
The content of the invention
The present invention is in the existing quantum repeater based on conventional magneto-optic trap of solution【Phys. Rev. Lett. 96,
093604 (2006), patent No. US 20080258049A1】, participate in four-wave mixing process is suitable for the storage of atom long-life
Wave band of laser and be suitable for the optical communication wave band of laser of optical fiber long-distance transmissions, light path is complicated and to be not engaged in atom cold
But, it is impossible to which the technical problem made full use of is there is provided a kind of Magneto-Optical Trap method and device of laser cooling and trapping, while proposing the
The various various combination modes of one cooling light and the second cooling light, device flexibly, meets the demand of various different potential applications.
A kind of Magneto-Optical Trap method of laser cooling and trapping of the present invention is realized using following technical scheme：One
The Magneto-Optical Trap method of laser cooling and trapping is planted, using the cooling laser and anti-pumping laser of two kinds of different wave lengths, with reference to anti-
Magneto-Optical Trap is constituted to Helmholtz coil, the atom to be cooled with capture is alkali metal atom；First cooling laser work is in suitable
The wave band stored together in the atom long-life, corresponding to the transition of alkali metal atom ground state to middle excitation state；Second cooling laser
Work in the optical communication wave band for being suitable for optical fiber long-distance transmissions, and corresponding to excitation state in the middle of alkali metal atom to higher
The transition of excitation state；Back suction transports laser work in the wave band for being suitable for the storage of alkali metal atom long-life, former corresponding to alkali metal
Transition of the subbase state to middle excitation state；Using the geometrically symmetric center of reverse Helmholtz coil as origin, Axisymmetric Distributed Line is z-axis
In identified three-dimensional coordinate, cooling laser is transmitted each along three reference axis：On first axle, two beams first cool down laser with
Opposite overlap mode is converged on origin, Article 2 axle, and two beams first cooling laser converges at origin with opposite overlap mode, the
On three axles, some cooling laser of beam first, second to penetrating combination to converge at origin, and it is one that described pair, which is penetrated combination,
Individual direction is a branch of second cooling laser or is a branch of first cooling laser and a branch of second cooling laser coincidence, other direction
For first cooling laser or be the second cooling laser or be it is a branch of first cooling laser and it is a branch of second cooling laser overlap；
Three axles correspond respectively to the combination of any order of x, y, z；The anti-pumping laser of two beams is along three dimensions any angle with phase
Origin is converged to overlap mode；Reverse Helmholtz coil produces quadripolar magnetic field, and magnetic field zero is located at the origin of coordinates, x directions,
The magnetic field gradient in y directions is equal in magnitude, and the magnetic field gradient size in z directions is twice of x directions；The reverse Helmholtz coil
Between be provided with internal-filling alkali metal atom vacuum room；The detection of atomic fluorescence signal by CCD black and white cameras, data collecting card and
Computer is completed.
The present invention and art methods【Phys. Rev. Lett. 103, 173003 (2009)】Compare, light path cloth
The advantage put is：In x-axis, two beams first cooling laser is converged in origin, y-axis with opposite overlap mode, and two beams first are cold
But laser is converged in origin, z-axis with opposite overlap mode, and some cooling laser of beam first, second are with to penetrating combination remittance
Gather in origin, its combination is as follows：（a）(L2)+(L2)；（b）(L1 L2)+(L2)；（c）(L1 L2)+(L1 L2)；（d）
(L1)+(L1 L2)；（e）(L1)+(L2) ；L1 represents the first cooling laser, and L2 represents the second cooling laser.And x, y, z three
The corresponding light path arrangement of axle can be exchanged arbitrarily, meet different experiment parameter demands, not enough in the second cooling laser power
In the case of suitable light path arrangement can also be selected to realize cooling.
The present invention is compared with art methods, and the advantage of cooling optical maser wavelength is：First cooling laser work is in suitable
The wave band stored together in the atom long-life, the second cooling laser work is in the optical communication ripple for being suitable for optical fiber long-distance transmissions
Section.The wavelength of the cooling laser of wavelength+the second of first cooling laser has following combination with the stepped transition energy level of atom：（a）
795nm+1324nm correspondences87Rb or85Rb atoms 5S1/2 – 5P1/2 – 6S1/2；（b）780nm+1367nm correspondences87Rb
Or85Rb atoms 5S1/2 – 5P3/2 – 6S1/2；（c）795nm+1476nm correspondences87Rb or85Rb atoms 5S1/2 - 5P1/2 –
4D3/2；（d）780nm+1529nm correspondences87Rb or85Rb atoms 5S1/2 - 5P3/2 – 4D3/2(5/2)；（e）895nm +
1359nm correspondences133Cs atoms 6S1/2 – 6P1/2 – 7S1/2；（f）852nm+1470nm correspondences133Cs atoms 6S1/2 –
6P3/2 – 7S1/2；（g）590nm+1138nm correspondence Na atoms 3S1/2 – 3P1/2 – 4S1/2；（h）589nm+1141nm correspondences Na
Atom 3S1/2 – 3P1/2 – 4S1/2；（i）770nm+1244nm correspondence Na atoms 4S1/2 – 4P1/2 – 5S1/2；（j）767nm+
1253nm correspondence K atoms 4S1/2 – 4P3/2 – 5S1/2；（k）770nm+1169nm correspondence K atoms 4S1/2 – 4P1/2 – 3D3/2；
（l）767nm+1177nm correspondence K atoms 4S1/2 – 4P3/2 – 3D3/2(5/2)。
The magneto-optic trap device of a kind of atom laser cooling of the present invention and capture is to adopt the following technical scheme that realization
's：A kind of magneto-optic trap device of atom laser cooling and capture, including internal-filling alkali metal atomic vapour vacuum room, by two kinds
The cooling laser and anti-pumping laser of different wave length, with reference to reverse Helmholtz coil constitute Magneto-Optical Trap；First cooling laser
The wave band for being suitable for the storage of atom long-life is worked in, corresponding to the transition of alkali metal atom ground state to middle excitation state；Second
Laser work is cooled down in the optical communication wave band for being suitable for optical fiber long-distance transmissions, and corresponding to exciting in the middle of alkali metal atom
Transition of the state to more highly excited level；Back suction transports laser work in the wave band for being suitable for the storage of alkali metal atom long-life, corresponds to
Transition of the alkali metal atom ground state to middle excitation state；Using the geometrically symmetric center of reverse Helmholtz coil as origin, axle pair
Line is called that determined by z-axis in three-dimensional coordinate, cooling laser is transmitted each along three reference axis：On first axle, two beams first
Cooling laser split-phase is converged on origin, Article 2 axle to overlap mode, and two beams first cooling laser is converged with opposite overlap mode
Gather on origin, Article 3 axle, some beams first, second cool down laser to converge at origin to penetrating combination, and described pair is penetrated
Combination is that a direction is a branch of second cooling laser or is that a branch of first cooling laser and a branch of second cool down laser
Overlap, other direction be the first cooling laser or be the second cooling laser or be it is a branch of first cooling laser and a branch of second
Laser is cooled down to overlap；Three axles correspond respectively to the combination of any order of x, y, z；The anti-pumping laser of two beams is along three dimensions
Any angle converges at origin with opposite overlap mode；Reverse Helmholtz coil produces quadripolar magnetic field, and magnetic field zero, which is located at, to be sat
Mark origin, x directions, y directions magnetic field gradient it is equal in magnitude, the magnetic field gradient size in z directions is twice of x directions；Vacuum gas
Room is located between reverse Helmholtz coil；Also include the CCD black and white cameras and CCD black and white for being used to gather atomic fluorescence signal
Data collecting card that camera signal output end is connected and the computer being connected with data collecting card signal output part.
Device of the present invention cooling and capture atom directly from room temperature hot atom vacuum room, available for original
The laser cooling and trapping of son storage wave band and the alkali metal atom of optical communication wave band；The cooling of atom is cooled down available for multi-photon
The research of mechanism；Application study available for the quantum repeater based on four-wave mixing.
Compared with prior art, in the present invention, a branch of or two beams cooling light is replaced with to the laser of communication band, both conduct
Second cooling beche-de-mer without spike and cooling, but also as the pump light of quantum state, and because the laser of intervention is few, system is more succinct,
It is not easily susceptible to the influence of the arrangement of geometry vacuum pipe of atomic air chamber etc..In addition, the present invention can be additionally used in atom storage
Wave band and the research in fiber optic communication wave band nondegenerate two photon source.
Brief description of the drawings
Wording employed herein, term are only used for the purpose rather than restricted purpose of description.Unless otherwise saying
Bright, terms used herein is consistent with the generic term implication of this area.
Fig. 1 --- solid line is light connects in the structural representation of device of the present invention, figure, and dotted line is electrical connection, bag
Include：
Back suction transports laser element：The 852nm semiconductor lasers of 1- the first, 2-852nm optical isolators, 3- first
The wave plates of 852nm 1/2nd, first cube of polarization splitting prism of 4-, the positive frequency shifting arrangement of 5- acousto-optic frequency shifters singles, 6- first is anti-
Penetrate mirror, 7- saturation-absorption spectrum frequency locking devices, 8- the first proportional integration amplifiers.
First cooling laser element：The 852nm semiconductor lasers of 9- the 2nd, 10-852nm optical isolators, 11- second
The wave plates of 852nm 1/2nd, second cube of polarization splitting prism of 12-, double negative frequency shift devices of 13- acousto-optic frequency shifters, 14- polarizations
Spectrum frequency locking device, 15- the second proportional integration amplifiers, the wave plates of the 3rd 852nm of 16- 1/2nd, the 3rd cube of polarization point of 17-
Light prism, 18- acousto-optic frequency shifters single negative frequency shift devices, double positive frequency shifting arrangements of 19- acousto-optic frequency shifters, 20- fibre-optic waveguides position
Facies pattern electrooptic modulator, the speculums of 21- second.
Second cooling laser element：22-1470nm semiconductor lasers, 23-1470nm optical isolators, 24-
The wave plates of 1470nm 1/2nd, the 4th cube of polarization splitting prism of 25-, the speculums of 26- the 3rd, the 852nm/1470nm of 27- the first
Double color plate, 28- detectors, 29- Cs atoms bubble, the 852nm/1470nm double color plates of 30- the 2nd, the wave plates of 31-1470nm 1/2nd,
The speculums of 32- the 4th, the 5th cube of polarization splitting prism of 33-, 34- differential detectors, the proportional integration amplifiers of 35- the 3rd.
852nm/1470nm double color plates can pass through 1470nm and reflect 852nm laser.
Magneto-Optical Trap light path arrangement unit：36 to 39 be respectively first, second, third, fourth group of 852nm cooling light and polarization
Control element, 40 be the 5th group of 852nm cooling light and polarization control component, 41-1470nm cooling light polarization control elements, 42-
The reverse Helmholtz coil of Magneto-Optical Trap.
Atomic fluorescence collector unit：43-CCD black and white cameras, 44- data collecting cards, 45- computers.
Fig. 2 --- involved 133Cs atomic energy level systems in the present invention.
Fig. 3 --- involved double-colored polarization spectrum rrequency-offset-lock second cools down the signal of light in the present invention.
Fig. 4 --- in the present invention involved Magneto-Optical Trap peak fluorescence with two-photon off resonance change.
Fig. 5 --- Magneto-Optical Trap peak fluorescence in the present invention under involved Magneto-Optical Trap z directions difference cooling light combination with
The change of two-photon off resonance.
Embodiment
A kind of Magneto-Optical Trap method of laser cooling and trapping, is transported using the cooling laser and back suction of two kinds of different wave lengths and swashed
Light, Magneto-Optical Trap is constituted with reference to reverse Helmholtz coil, and the atom to be cooled with capture is alkali metal atom；First cooling laser
The wave band for being suitable for the storage of atom long-life is worked in, corresponding to the transition of alkali metal atom ground state to middle excitation state；Second
Laser work is cooled down in the optical communication wave band for being suitable for optical fiber long-distance transmissions, and corresponding to exciting in the middle of alkali metal atom
Transition of the state to more highly excited level；Back suction transports laser work in the wave band for being suitable for the storage of alkali metal atom long-life, corresponds to
Transition of the alkali metal atom ground state to middle excitation state；Using the geometrically symmetric center of reverse Helmholtz coil as origin, axle pair
Line is called that determined by z-axis in three-dimensional coordinate, cooling laser is transmitted each along three reference axis：On first axle, two beams first
Cooling laser is converged on origin, Article 2 axle with opposite overlap mode, and two beams first cooling laser is converged with opposite overlap mode
Gather on origin, Article 3 axle, some beams first, second cool down laser to converge at origin to penetrating combination, and described pair is penetrated
Combination is that a direction is a branch of second cooling laser or is that a branch of first cooling laser and a branch of second cool down laser
Overlap, other direction be the first cooling laser or be the second cooling laser or be it is a branch of first cooling laser and a branch of second
Laser is cooled down to overlap；Three axles correspond respectively to the combination of any order of x, y, z；The anti-pumping laser of two beams is along three dimensions
Any angle converges at origin with opposite overlap mode；Reverse Helmholtz coil produces quadripolar magnetic field, and magnetic field zero, which is located at, to be sat
Mark origin, x directions, y directions magnetic field gradient it is equal in magnitude, the magnetic field gradient size in z directions is twice of x directions；It is described anti-
To the vacuum room that internal-filling alkali metal atom is provided between Helmholtz coil；The detection of atomic fluorescence signal is by CCD black and white phases
Machine 43, data collecting card 44 and computer 45 are completed.
The wavelength of the cooling laser of wavelength+the second of first cooling laser is with the stepped transition energy level of atom just like the following group
Close：（a）795nm+1324nm correspondences87Rb or85Rb atoms 5S1/2 – 5P1/2 – 6S1/2；（b）+ 1367nm couples of 780nm
Should87Rb or85Rb atoms 5S1/2 – 5P3/2 – 6S1/2；（c）795nm+1476nm correspondences87Rb or85Rb atoms 5S1/2 -
5P1/2 – 4D3/2；（d）780nm+1529nm correspondences87Rb or85Rb atoms 5S1/2 - 5P3/2 – 4D3/2(5/2)；（e）895nm
+ 1359nm correspondences133Cs atoms 6S1/2 – 6P1/2 – 7S1/2；（f）852nm+1470nm correspondences133Cs atoms 6S1/2 –
6P3/2 – 7S1/2；（g）590nm+1138nm correspondence Na atoms 3S1/2 – 3P1/2 – 4S1/2；（h）589nm+1141nm correspondences Na
Atom 3S1/2 – 3P1/2 – 4S1/2；（i）770nm+1244nm correspondence Na atoms 4S1/2 – 4P1/2 – 5S1/2；（j）767nm+
1253nm correspondence K atoms 4S1/2 – 4P3/2 – 5S1/2；（k）770nm+1169nm correspondence K atoms 4S1/2 – 4P1/2 – 3D3/2；
（l）767nm+1177nm correspondence K atoms 4S1/2 – 4P3/2 – 3D3/2(5/2)。
In x-axis, two beams first cooling laser is converged in origin, y-axis with opposite overlap mode, two beams first cooling laser
Converged at opposite overlap mode in origin, z-axis, some beams first, second cool down laser to converge at original to penetrating combination
Point, its combination is as follows：（a）(L2)+(L2)；（b）(L1 L2)+(L2)；（c）(L1 L2)+(L1 L2)；（d）(L1)+(L1
L2)；（e）(L1)+(L2) ；L1 represents the first cooling laser, and L2 represents the second cooling laser.
Atom to be cooled with capture is that alkali metal atom is Cs atom；First cooling optical maser wavelength is 852 nm, with caesium
Atomic ground state 6S1/2F=4 are to middle excitation state 6P3/2The single photon off resonance Δ of the transition of F=51For -5 MHz of MHz to -25；Second is cold
But optical maser wavelength is 1470 nm, with excitation state 6P in the middle of Cs atom3/2F=5 are to more highly excited level 7S3/2The single photon of the transition of F=4
Off resonance Δ2For -100 MHz of MHz to+100；Back suction transports laser wave with two values, and one is 852 nm, is resonated in Cs atom
Ground state 6S1/2F=3 are to excitation state 6P3/2F=4 or 3 transition line；Another value is 894 nm, is resonated in Cs atom ground state 6S1/2F=
3 to excitation state 6P1/2F=4 or 3 transition line；The quadripolar magnetic field gradient that reverse Helmholtz coil is produced is 10 Gauss/cm.
Pressure in vacuum room is 10-6~10-8Pa, vacuum state is maintained by ionic pump, vacuum room at least six
Thang-kng window perpendicular to each other.
A kind of magneto-optic trap device of atom laser cooling and capture, including internal-filling alkali metal atomic vapour vacuum room,
Magneto-Optical Trap is constituted by the cooling laser and anti-pumping laser of two kinds of different wave lengths, with reference to reverse Helmholtz coil；First is cold
But laser work is in the wave band for being suitable for the storage of atom long-life, corresponding to the jump of alkali metal atom ground state to middle excitation state
Move；Second cooling laser work corresponds to alkali metal atom in the optical communication wave band for being suitable for optical fiber long-distance transmissions
Transition of the middle excitation state to more highly excited level；Back suction transports laser work in the ripple for being suitable for the storage of alkali metal atom long-life
Section, corresponding to the transition of alkali metal atom ground state to middle excitation state；Using the geometrically symmetric center of reverse Helmholtz coil as
Origin, Axisymmetric Distributed Line is that determined by z-axis in three-dimensional coordinate, cooling laser is transmitted each along three reference axis：On first axle,
Two beams first cooling laser split-phase is converged on origin, Article 2 axle to overlap mode, and two beams first cool down laser to weigh in opposite directions
Folded mode is converged on origin, Article 3 axle, and some beams first, second cool down laser to converge at origin to penetrating combination,
Described pair penetrate combination be a direction be it is a branch of second cooling laser or be it is a branch of first cooling laser and a branch of second
Cool down laser overlap, other direction be the first cooling laser or be the second cooling laser or be it is a branch of first cooling laser and
A branch of second cooling laser is overlapped；Three axles correspond respectively to the combination of any order of x, y, z；The anti-pumping laser of two beams along
Three dimensions any angle converges at origin with opposite overlap mode；Reverse Helmholtz coil produces quadripolar magnetic field, magnetic field zero
Point be located at the origin of coordinates, x directions, y directions magnetic field gradient it is equal in magnitude, the magnetic field gradient size in z directions is the two of x directions
Times；Vacuum room is located between reverse Helmholtz coil；Also include the CCD black and white cameras for being used to gather atomic fluorescence signal
43rd, the data collecting card 44 that is connected with the signal output part of CCD black and white cameras 43 and with the signal output part of data collecting card 44
The computer 45 being connected.
For ease of illustration the realization of technical scheme, by taking following actual conditionses as an example：Alkali metal atom is Cs atom, two coolings
Optical wavelength and correspondence energy level are 852nm+1470nm133Cs atoms 6S1/2 – 6P3/2 – 7S1/2, anti-pumping light correspondence D2 lines
（Or D1 lines）.To complete Magneto-Optical Trap component units one by one letter continue it is as follows：
（1）Back suction fortune laser element includes：The 852nm semiconductor lasers of 1- the first, 2-852nm optical isolators, 3-
The wave plates of first 852nm 1/2nd, first cube of polarization splitting prism of 4-, the positive frequency shifting arrangement of 5- acousto-optic frequency shifters singles, 6-
One speculum, 7- saturation-absorption spectrum frequency locking devices, 8- the first proportional integration amplifiers.Wherein, the ripples of the first 852nm 1/2nd
Piece 3 and first cube of combined adjustable laser power of polarization splitting prism 4, the radio frequency of the positive frequency shifting arrangement 5 of acousto-optic frequency shifters single
Frequency is RF1=100.64 MHz, saturation-absorption spectrum frequency locking to 6S1/2F=3 are to 6P3/2On the cross spider of F=3,4.
（2）First cooling laser element includes：The 852nm semiconductor lasers of 9- the 2nd, 10-852nm optical isolators,
The wave plates of the 2nd 852nm of 11- 1/2nd, second cube of polarization splitting prism of 12-, double negative frequency shift devices of 13- acousto-optic frequency shifters,
14- polarization spectrum frequency locking devices, 15- the second proportional integration amplifiers, the wave plates of the 3rd 852nm of 16- 1/2nd, 17- the 3rd is stood
Square polarization splitting prism, 18- acousto-optic frequency shifters single negative frequency shift devices, double positive frequency shifting arrangements of 19- acousto-optic frequency shifters, 20- light
Fiber wave guide phase-type electrooptic modulator, the speculums of 21- second.Wherein, the radio frequency frequency of double negative frequency shift devices 13 of acousto-optic frequency shifters
Rate is RF2=96.52 MHz（Adjustable range is between 100.27 ~ 90.27 MHz）, the perseverance of acousto-optic frequency shifters single negative frequency shift device 18
For RF3=80.00 MHz, the single photon off resonance that correspondence obtains the first cooling laser is Δ1=2×RF2- 125.54-80.00=-
12.5 MHz （Adjustable range is between -5 MHz of MHz to -25）.The rf frequency of double positive frequency shifting arrangements 19 of acousto-optic frequency shifters is permanent
For RF4=80.00MHz.Fibre-optic waveguide phase-type electrooptic modulator（Itself tuned radio-frequency scope is from ~ MHz to 10GHz）Radio frequency
Frequency is RF5Adjustable range be 90.00 ~ 410.00 MHz, the size of radio-frequency power causes the sideband and dominant frequency work(of output light
Rate is close to be defined.
（3）Second cooling laser element includes：22-1470nm semiconductor lasers, 23-1470nm optical isolators,
The wave plates of 24-1470nm 1/2nd, the 4th cube of polarization splitting prism of 25-, the speculums of 26- the 3rd, the 852nm/ of 27- the first
1470nm double color plates, 28- detectors, 29- Cs atoms bubble, the 852nm/1470nm double color plates of 30- the 2nd, 31-1470nm bis-/
One wave plate, the speculums of 32- the 4th, the 5th cube of polarization splitting prism of 33-, 34- differential detectors, the proportional integrations of 35- the 3rd are put
Big device.Wherein, the signal for the double-colored polarization spectrum rrequency-offset-lock second cooling laser that differential detector is obtained is as shown in Figure 3.Most
Eventually, the single photon off resonance of the second cooling laser is Δ2 =(RF5-(2*RF4+80+Δ1))*852.3/1470 =(RF5-(2*RF4+
2*RF2-125.54))*852.3/1470 .So, the single photon off resonance of the second cooling laser can be by RF2、RF4And RF5Collaboration
Regulation, works as RF2=96.52 MHz（That is Δ1=-12.5 MHz）, RF4=80.00 MHz, RF5During=90.00 ~ 410.00 MHz, Δ2
=( RF5-(2*80+2*96.52-125.54))*852.3/1470 =-79.72~+105.81 MHz.Two-photon off resonance δ2=Δ1
+Δ2 = -92.22 MHz~+ 93.31 MHz。
（4）Magneto-Optical Trap light path arrangement unit：36 to 39 be first, second, third, fourth group of 852nm cooling laser and inclined
Shake control element, and 40 be the 5th group of 852nm cooling laser and polarization control component, 41-1470nm cooling laser polarization control members
Part, the reverse Helmholtz coil of 42- Magneto-Optical Traps.Wherein, 40 to the 41 cooling light in z directions is replaceable or can be such as the following group
Conjunction mode（First cooling laser represents that the second cooling laser is represented with L2 with L1）Any embodiment：（a）(L2)+
(L2)；（b）(L1 L2)+(L2)；（c）(L1 L2)+(L1 L2)；（d）(L1)+(L1 L2)；（e）(L1)+(L2).And x, y,
The corresponding light path arrangement of the axles of z tri- can be exchanged arbitrarily, meet different experiment parameter demands, not enough in the second cooling luminous power
In the case of suitable light path arrangement can also be selected to realize cooling.
（5）Atomic fluorescence collector unit includes：43-CCD black and white cameras, 44- data collecting cards, 45- computers.Computer
It is acquired and handles in real time using the common experimental software such as MATLAB, LabVIEW, obtains atom peak fluorescence and atomic group
The information such as relative size.
When it is implemented, the above-mentioned device related to acousto-optic frequency shifters, can use centre frequency for 80 MHz, bandwidth 30
MHz, is operable with 852nm commercial acousto-optic frequency shift, and the radio-frequency power loaded reaches that peak power is defined by diffraction light.
Concrete operation step is as follows in practical application：
（1）Back suction fortune laser element is built according to Fig. 1, wherein, the wave plates 3 of the first 852nm 1/2nd and first cube
The combined adjustable laser power of polarization splitting prism 4；The rf frequency of the positive frequency shifting arrangement 5 of acousto-optic frequency shifters single is RF1=
100.64 MHz；Scanning laser frequency, saturation-absorption spectrum frequency locking device 7 obtains saturation-absorption spectrum signal and corresponding frequency discrimination letter
Number, monitored with oscillograph, frequency scanning amplitude is progressively decreased to finely tune laser frequency while zero, is put using the first proportional integration
Big device 8,6S is locked into by laser frequency1/2F=3 are to 6P3/2On the cross spider of F=3,4.
（2）The first cooling laser element is built according to Fig. 1, wherein, acousto-optic frequency shifters double negative frequency shift devices 13 are penetrated
Frequent rate is RF2=96.52 MHz（Adjustable range is between 100.27 ~ 90.27 MHz）, acousto-optic frequency shifters single negative frequency shift device
18 is permanent for RF3=80.00 MHz, the single photon off resonance that correspondence obtains the first cooling laser is Δ1=2×RF2- 125.54-
80.00=-12.5 MHz （Adjustable range is between -5 MHz of MHz to -25）.Acousto-optic frequency shifters double positive frequency shifting arrangements 19 are penetrated
Frequent rate perseverance is RF4=80.00MHz.Fibre-optic waveguide phase-type electrooptic modulator 20（Itself tuned radio-frequency scope from ~ MHz extremely
10GHz）Rf frequency be RF5Adjustable range be at least 90.00 ~ 410.00 MHz, the size of radio-frequency power causes output
The sideband and dominant frequency power of light are close to be defined.
（3）The second cooling laser element is built according to Fig. 1, wherein, the double-colored polarization spectrum that differential detector is obtained is inclined
The signal that frequency locking second cools down light is as shown in Figure 3.Finally, the single photon off resonance of the second cooling laser is Δ2 =(RF5-(2*
RF4+80+Δ1))*852.3/1470 =(RF5-(2*RF4+2*RF2-125.54))*852.3/1470 .So, the second cooling swashs
The single photon off resonance of light can be by RF2、RF4And RF5Synergic adjustment, works as RF2=96.52 MHz（That is Δ1=-12.5 MHz）, RF4=
80.00 MHz, RF5During=90.00 ~ 410.00 MHz, Δ2 =( RF5-(2*80+2*96.52-125.54))*852.3/1470
=-79.72~+105.81 MHz.Two-photon off resonance δ2=Δ1 +Δ2= -92.22 MHz~+ 93.31 MHz.What is obtained is double-colored inclined
Vibrational spectrum rrequency-offset-lock signal such as Fig. 3.
（4）Magneto-Optical Trap light path arrangement unit is built according to Fig. 1, wherein, 40 to the 41 cooling light in z directions is replaceable or can
To be following combination（First cooling laser represents that the second cooling laser is represented with L2 with L1）Any embodiment party
Case：（a）(L2)+(L2)；（b）(L1 L2)+(L2)；（c）(L1 L2)+(L1 L2)；（d）(L1)+(L1 L2)；（e）(L1)+
(L2).And the corresponding light path arrangement of the axle of x, y, z three can be exchanged arbitrarily, different experiment parameter demands are met, it is cold second
But it can also select suitable light path arrangement to realize cooling in the case that laser power is not enough.Arriving under various combination mode
Atomic group peak fluorescence signal is as shown in Figure 5 with the change of two-photon off resonance.
（5）Atomic fluorescence collector unit is built according to Fig. 1, it is defeated by the alignment lenses atom cluster centre of CCD black and white cameras 43
Go out signal access data collecting card 44, capture card data are received with computer.Computer can be using MATLAB, LabVIEW etc. often
It is acquired and is handled in real time with experiment software, obtains the information such as atom peak fluorescence and atomic group relative size.
As it will be easily appreciated by one skilled in the art that the foregoing is only the preferred embodiments of the present invention, limit is not used to
The system present invention, any change, equivalent substitution and the improvement made within the spirit and principles of the invention etc., it should be included in
Within protection scope of the present invention.
Claims (5)
1. a kind of Magneto-Optical Trap method of laser cooling and trapping, it is characterised in that use the cooling laser of two kinds of different wave lengths with
And anti-pumping laser, Magneto-Optical Trap is constituted with reference to reverse Helmholtz coil, the atom to be cooled with capture is alkali metal atom；The
One cooling laser work is in the wave band for being suitable for the storage of atom long-life, corresponding to alkali metal atom ground state to middle excitation state
Transition；Second cooling laser work is in the optical communication wave band for being suitable for optical fiber long-distance transmissions, and it is former to correspond to alkali metal
Transition of the excitation state to more highly excited level in the middle of sub；Back suction transports laser work in the ripple for being suitable for the storage of alkali metal atom long-life
Section, corresponding to the transition of alkali metal atom ground state to middle excitation state；Using the geometrically symmetric center of reverse Helmholtz coil as
Origin, Axisymmetric Distributed Line is that determined by z-axis in three-dimensional coordinate, cooling laser is transmitted each along three reference axis：On first axle,
Two beams first cooling laser is converged on origin, Article 2 axle with opposite overlap mode, and two beams first cool down laser to weigh in opposite directions
Folded mode is converged on origin, Article 3 axle, and some beams first, second cool down laser to converge at origin to penetrating combination,
Described pair penetrate combination be a direction be it is a branch of second cooling laser or be it is a branch of first cooling laser and a branch of second
Cool down laser overlap, other direction be the first cooling laser or be the second cooling laser or be it is a branch of first cooling laser and
A branch of second cooling laser is overlapped；Three axles correspond respectively to the combination of any order of x, y, z；The anti-pumping laser of two beams along
Three dimensions any angle converges at origin with opposite overlap mode；Reverse Helmholtz coil produces quadripolar magnetic field, magnetic field zero
Point be located at the origin of coordinates, x directions, y directions magnetic field gradient it is equal in magnitude, the magnetic field gradient size in z directions is the two of x directions
Times；The vacuum room of internal-filling alkali metal atom is provided between the reverse Helmholtz coil；The detection of atomic fluorescence signal by
CCD black and white cameras（43）, data collecting card（44）And computer（45）Complete；
The wavelength of the cooling laser of wavelength+the second of first cooling laser has following combination with the stepped transition energy level of atom：（a）
795nm+1324nm correspondences87Rb or85Rb atoms 5S1/2 – 5P1/2 – 6S1/2；（b）780nm+1367nm correspondences87Rb
Or85Rb atoms 5S1/2 – 5P3/2 – 6S1/2；（c）795nm+1476nm correspondences87Rb or85Rb atoms 5S1/2 - 5P1/2 –
4D3/2；（d）780nm+1529nm correspondences87Rb or85Rb atoms 5S1/2 - 5P3/2 – 4D3/2(5/2)；（e）895nm +
1359nm correspondences133Cs atoms 6S1/2 – 6P1/2 – 7S1/2；（f）852nm+1470nm correspondences133Cs atoms 6S1/2 –
6P3/2 – 7S1/2；（g）590nm+1138nm correspondence Na atoms 3S1/2 – 3P1/2 – 4S1/2；（h）589nm+1141nm correspondences Na
Atom 3S1/2 – 3P1/2 – 4S1/2；（i）770nm+1244nm correspondence Na atoms 4S1/2 – 4P1/2 – 5S1/2；（j）767nm+
1253nm correspondence K atoms 4S1/2 – 4P3/2 – 5S1/2；（k）770nm+1169nm correspondence K atoms 4S1/2 – 4P1/2 – 3D3/2；
（l）767nm+1177nm correspondence K atoms 4S1/2 – 4P3/2 – 3D3/2(5/2)。
2. the Magneto-Optical Trap method of a kind of laser cooling and trapping as claimed in claim 1, it is characterised in that in x-axis, two beams the
One cooling laser is converged in origin, y-axis with opposite overlap mode, and two beams first cooling laser is converged at opposite overlap mode
In origin, z-axis, some beams first, second cool down laser to converge at origin to penetrating combination, and its combination is as follows：（a）
(L2)+(L2)；（b）(L1 L2)+(L2)；（c）(L1 L2)+(L1 L2)；（d）(L1)+(L1 L2)；（e）(L1)+(L2) ；L1
Represent that first cools down laser, L2 represents the second cooling laser.
3. the Magneto-Optical Trap method of a kind of laser cooling and trapping as claimed in claim 1, it is characterised in that to be cooled with capturing
Atom be that alkali metal atom is Cs atom；First cooling optical maser wavelength is 852 nm, with Cs atom ground state 6S1/2F=4 to centre
Excitation state 6P3/2The single photon off resonance Δ of the transition of F=51For -5 MHz of MHz to -25；Second cooling optical maser wavelength is 1470 nm,
With excitation state 6P in the middle of Cs atom3/2F=5 are to more highly excited level 7S3/2The single photon off resonance Δ of the transition of F=42For -100 MHz to+
100 MHz；Back suction transports laser wave with two values, and one is 852nm, is resonated in Cs atom ground state 6S1/2F=3 are to excitation state
6P3/2F=4 or 3 transition line；Another value is 894 nm, is resonated in Cs atom ground state 6S1/2F=3 are to excitation state 6P1/2F=4 or 3
Transition line；The quadripolar magnetic field gradient that reverse Helmholtz coil is produced is 8 Gauss/cm to 15Gauss/cm.
4. a kind of method of the Magneto-Optical Trap of laser cooling and trapping as claimed in claim 1, it is characterised in that in vacuum room
Pressure be 10-6~10-8Pa, vacuum state is maintained by ionic pump, at least six thang-kng windows perpendicular to each other of vacuum room.
5. a kind of magneto-optic trap device of laser cooling and trapping, for realizing the method as described in claim 1, its feature exists
In including vacuum room, the cooling laser and anti-pumping laser, knot by two kinds of different wave lengths of internal-filling alkali metal atomic vapour
Close reverse Helmholtz coil composition Magneto-Optical Trap；First cooling laser work is right in the wave band for being suitable for the storage of atom long-life
Should be in the transition of alkali metal atom ground state to middle excitation state；Second cooling laser work is in being suitable for optical fiber long-distance transmissions
Optical communication wave band, and corresponding to the transition of excitation state in the middle of alkali metal atom to more highly excited level；Back suction transports laser work
In the wave band for being suitable for the storage of alkali metal atom long-life, corresponding to the transition of alkali metal atom ground state to middle excitation state；
Using the geometrically symmetric center of reverse Helmholtz coil as origin, Axisymmetric Distributed Line is determined by z-axis in three-dimensional coordinate, to cool down laser
Each along three reference axis transmission：On first axle, two beams first cooling laser split-phase converges at origin, second to overlap mode
On bar axle, two beams first cooling laser is converged on origin, Article 3 axle with opposite overlap mode, and some beams first, second are cold
But laser is to penetrating combination to converge at origin, described pair penetrate combination be a direction be a branch of second cooling laser or
Person is that a branch of first cooling laser and a branch of second cooling laser are overlapped, and other direction is the first cooling laser or is second cold
But laser or for a branch of first cooling laser and it is a branch of second cooling laser overlap；Three axles correspond respectively to appointing for x, y, z
The combination of meaning order；The anti-pumping laser of two beams converges at origin along three dimensions any angle with opposite overlap mode；Reversely
Helmholtz coil produce quadripolar magnetic field, magnetic field zero be located at the origin of coordinates, x directions, y directions magnetic field gradient it is equal in magnitude, z
The magnetic field gradient size in direction is twice of x directions；Vacuum room is located between reverse Helmholtz coil；Also include being used to adopt
Collect the CCD black and white cameras of atomic fluorescence signal（43）And CCD black and white cameras（43）The data collecting card that signal output part is connected
（44）And and data collecting card（44）The computer that signal output part is connected（45）.
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| US11467330B1 (en) | 2018-10-23 | 2022-10-11 | Government Of The United States As Represented By The Secretary Of The Air Force | One beam mirror magneto-optical trap chamber |
| CN109920575B (en) * | 2019-03-20 | 2020-08-25 | 中国人民解放军国防科技大学 | Self-cooling laser optical tweezers device and method based on two-dimensional optical trap |
| GB2595746B (en) * | 2020-10-29 | 2022-06-01 | Univ Southampton | Atomic cooling and trapping methods and apparatus |
| CN113808774A (en) * | 2021-08-02 | 2021-12-17 | 西南科技大学 | Coherent electron source acquisition device based on magneto-optical trap |
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| CN1087115C (en) * | 1998-12-10 | 2002-07-03 | 山西大学 | Single-frequency frequency-doubling solid laser |
| US8237105B1 (en) * | 2011-02-03 | 2012-08-07 | Northrop Grumman Guidance & Electronics Company, Inc. | Magneto-optical trap for cold atom beam source |
| CN102519928B (en) * | 2011-12-13 | 2013-05-22 | 山西大学 | Detection method capable of realizing direct acquirement of image of single atom |
| CN104036841A (en) * | 2014-07-01 | 2014-09-10 | 山西大学 | Bi-color magneto-optical trap method and device for cooling and capturing atoms through lasers |
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| CN1087115C (en) * | 1998-12-10 | 2002-07-03 | 山西大学 | Single-frequency frequency-doubling solid laser |
| US8237105B1 (en) * | 2011-02-03 | 2012-08-07 | Northrop Grumman Guidance & Electronics Company, Inc. | Magneto-optical trap for cold atom beam source |
| CN102519928B (en) * | 2011-12-13 | 2013-05-22 | 山西大学 | Detection method capable of realizing direct acquirement of image of single atom |
| CN104036841A (en) * | 2014-07-01 | 2014-09-10 | 山西大学 | Bi-color magneto-optical trap method and device for cooling and capturing atoms through lasers |
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