CN102023563B - Method, apparatus and system for eliminating deposit of atoms on Zeemcooling window - Google Patents
Method, apparatus and system for eliminating deposit of atoms on Zeemcooling window Download PDFInfo
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- CN102023563B CN102023563B CN2009100939023A CN200910093902A CN102023563B CN 102023563 B CN102023563 B CN 102023563B CN 2009100939023 A CN2009100939023 A CN 2009100939023A CN 200910093902 A CN200910093902 A CN 200910093902A CN 102023563 B CN102023563 B CN 102023563B
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Abstract
The present invention discloses a method, an apparatus and a system for eliminating the deposit of atoms on a Zeeman cooling window in a strontium atom optical clock. A strontium atom optical clock system is provided with, in a linear order along the direction of the atomic beam, an atomic pile which emits the atomic beam, a magneto-optical trap which confines the atoms and the Zeeman cooling window. In at least one area of the zones from an emission port of the atomic pile to the Zeeman cooling window, excluding the magneto-optical trap, the resonance light of to-be-removed atoms is used to irradiate the motion path of the atoms along a direction at an angle with the motion path of the strontium atom beam so that the atoms cannot reach the Zeeman cooling window. The present invention creates transverse velocity of the atoms through irradiation to prevent the atoms from reaching the Zeeman cooling window, effectively eliminating the deposit of the atoms on the glass of the Zeeman cooling window in an atomic optical clock system and maintaining the high transparency of the window glass.
Description
Technical field
The present invention relates to atom light clock technical field, refer to especially a kind of methods, devices and systems of atom in Zeeman cooling window deposition of removing in the strontium atom light clock.
Background technology
At present, international time and frequency standard is provided by caesium (Cs) atomic fountain clock, and the light clock that application strontium (Sr) atom is made has higher accuracy and degree of stability, so the atom light clock is the focus of studying on our times.
The structure of atom light clock system as shown in Figure 1.Strontium element is placed in atomic pile 101, one collimation device 102 is arranged in atomic pile, heating atomic pile, atom just with the form of line from atomic pile, penetrating, after Zeeman speed reduction unit 103, imprison in the Magneto-Optical Trap (MOT) 104 of magnetic field and six bundle light compositions, and then carry out frequency sonding.
There is a glass window in the place just relative with atomic beam, is called Zeeman cooling window 105, is used for the cooling light of incident Zeeman.At Magneto-Optical Trap, also do not have in harness the time, hot atom can directly be got on cold windowpane 105, and deposition rapidly on glass window 105, pollute window, thereby the transmitance of light is reduced greatly, causes the adverse effect to atom cooling and imprison.In actual experiment, though Magneto-Optical Trap 104 normal operations, or some atom can arrive window 105; In any case and, atom used, the atom of the imprison that namely is hunted down is a kind of in several isotopes, and useless isotope atom all can arrive window 105.
The method that prior art is generally applied is the window heating, to the glass window heating, allows window remain on higher temperature, and atom deposits just considerably less on hot window, therefore can guarantee the clean of window.Generally adopt heating tape or utilize the illumination heating, as utilize heating tape, heating tape to be wrapped on the window flange; As utilizing illumination heating time, light is focused on the center of window.
Heating is passive method, need to add thermal window, but the MOT zone needs low temperature, therefore high temperature window Hui Dui MOT district is influential, and if while adopting the illumination heating, a small amount of light can enter to inject the MOT district by window, the collection of MOT signal there is is strong interference and produces optical frequency shift.
Summary of the invention
In view of this, the object of the invention is to propose in a kind of strontium atom light clock remove the methods, devices and systems of atom in Zeeman cooling window deposition, solve better the window glass pollution problem caused in the deposition of atom light clock Atom on the Zeeman cooling window.
Based in above-mentioned purpose a kind of strontium Sr atom light clock system provided by the invention, removing the method for atom in Zeeman cooling window deposition, in described strontium atom light clock system, on the atomic beam direction, be in line and be laid with successively be used to the atomic pile of launching atomic beam, for Magneto-Optical Trap and the Zeeman cooling window of Trapping of Atoms, wherein
At the emission port from described atomic pile except described Magneto-Optical Trap, at least one zone described Zeeman cooling window, use with the laser of atomic resonance to be removed and along an angle, the atomic beam motion path is irradiated so that atom finally can't arrive the Zeeman cooling window.
Optionally, if the described irradiation light of the method more than a branch of, each is restrainted irradiating laser and irradiates in the same direction at diverse location, or irradiates along different but non-opposite direction at diverse location, or irradiates along different but non-opposite direction at same position.
Optionally, the described irradiation light of the method irradiates by the window that is used as two-dimensional collimation in described strontium atom light clock system.
Optionally, the method when the zone of described irradiation be from the emission port of described atomic pile to described Magneto-Optical Trap entrance the time, described irradiation light be with
87The laser of other isotope resonance beyond Sr; When from described Magneto-Optical Trap, exporting between described Zeeman cooling window, described irradiation light be the laser with all high abundance isotopes resonance of strontium atom when the zone of described irradiation, or the laser that resonates of a kind of high abundance isotope wherein.
Optionally, the method described with
87Beyond Sr the light of other isotopes resonance be with
88The laser of Sr isotope resonance; The light of all high abundance isotopes resonance of described and strontium atom be with
87Sr and
86Sr and
88The laser of Sr resonance.
Optionally, the zone of the described irradiation of the method is: from the emission port of described atomic pile to described Magneto-Optical Trap entrance, and export between described Zeeman cooling window and simultaneously the atomic motion path is irradiated from described Magneto-Optical Trap.
Optionally, the described irradiation irradiation of the method direction is vertical with the direction of strontium atom Shu Yundong.
Optionally, the method when the zone of described irradiation be from the emission port of described atomic pile to described Magneto-Optical Trap entrance the time, the centre wavelength of described laser is 460.862nm, line width or sweep length are 10MHz;
When the zone of described irradiation is that while from described Magneto-Optical Trap, exporting between described Zeeman cooling window, the centre wavelength of described laser is 460.862nm, the line width of described laser or sweep length are 100,000,000 magnitudes.
Optionally, the method when the zone of described irradiation be from the emission port of described atomic pile to described Magneto-Optical Trap entrance the time, scan mode is adopted in described irradiation light emission, sweep limit 10MHz, sweep velocity is at least
When the zone of described irradiation is while from described Magneto-Optical Trap, exporting between described Zeeman cooling window, multi-frequency light beam synthesis mode is adopted in described irradiation light emission.
Optionally, the method when the zone of described irradiation be from the emission port of described atomic pile to described Magneto-Optical Trap entrance the time, the action length of described irradiation light on the atomic beam direction is at least
Rice, wherein, V is the atomic beam longitudinal velocity, and R is Zeeman cooling window radius, and m is atomic mass, and S is the ratio of actual light intensity and saturated light intensity, and τ is the transition probability of atom, and k is the photon wave vector,
For Planck's constant, L is for irradiating the length of light incidence window to the Zeeman cooling window;
When the zone of described irradiation is that while from described Magneto-Optical Trap, exporting between described Zeeman cooling window, the action length of described irradiation light on the atomic beam direction is
Wherein V ' is atomic velocity herein, and L ' is the distance that arrives from here the Zeeman cooling window.
Optionally, the method irradiation light is that 5mm is between 20mm in the action length scope on the atomic beam direction.
Based on above-mentioned purpose, the invention allows in a kind of strontium atom light clock system and remove the device of atom in the window deposition, in described strontium atom light clock system, on the atomic beam direction, be in line and be laid with successively be used to the atomic pile of launching atomic beam, for Magneto-Optical Trap and the Zeeman cooling window of Trapping of Atoms, comprise at this device:
Laser instrument, be used to sending the laser with atomic resonance to be removed; And
Optical path adjusting equipment, for the laser that laser instrument sends can, at the emission port from described atomic pile except described Magneto-Optical Trap at least one zone described Zeeman cooling window, be irradiated so that atom finally can't arrive the Zeeman cooling window the atomic motion path along an angle.
Optionally, the described optical path adjusting equipment of this device also comprises: parallel beam expand device expands for the laser beam that laser instrument is sent.
Optionally, the described parallel beam expand device of this device is extender lens pair, and described extender lens for wishing the beam radius obtained and original beam radius ratio, is coated with anti-reflection film on right each lens of described extender lens to the latter and the former's focal distance ratio.
Optionally, in the described optical path adjusting equipment of this device, also comprise: half-wave plate rotates the laser polarization direction that semiconductor laser sends;
Polarization spectroscope, make through the postrotational laser beam of half-wave plate after polarization spectroscope, part light is reflected, in an irradiation area, described atomic beam motion path is irradiated therein, another part light is transmitted in another irradiation area described atomic beam motion path is irradiated.
Optionally, the optical maser wavelength of the described laser instrument emission of this device is 460.862nm.
Optionally, this device when the zone of described irradiation be from the emission port of described atomic pile to described Magneto-Optical Trap entrance the time, described irradiation light be with
87The laser of other isotope resonance beyond Sr; When from described Magneto-Optical Trap, exporting between described Zeeman cooling window, described irradiation light be the laser with all high abundance isotopes resonance of strontium atom when the zone of described irradiation, or the laser that resonates of a kind of high abundance isotope wherein.
Optionally, this device described with
87Beyond Sr the light of other isotopes resonance be with
88The laser of Sr isotope resonance; The light of all high abundance isotopes resonance of described and strontium atom be with
87Sr and
86Sr and
88The laser of Sr resonance.
Optionally, also comprise in the described optical path adjusting equipment of this device: first, second, third and fourth sound photomodulator, for the centre frequency by light, increase or reduce a fixed value;
The first sound CD-ROM driver, as the automatically controlled part of first sound-optic modulator, drive the signal center frequency correspondence
88Sr jump frequency and laser instrument output frequency are poor;
Second sound CD-ROM driver, as the automatically controlled part of second sound-optic modulator, drive the signal center frequency correspondence
86Sr jump frequency and laser instrument output frequency are poor;
The 3rd acousto-optic driver, as the automatically controlled part of the 3rd acousto-optic modulator, drive the signal center frequency correspondence
87Sr jump frequency and laser instrument output frequency are poor;
Fourth sound CD-ROM driver, as the automatically controlled part of fourth sound photomodulator, drive the signal center frequency correspondence
88Sr jump frequency and laser instrument output frequency are poor.
Optionally, this device described first, second, third and fourth sound CD-ROM driver, modulation range is 10MHz be used to enlarging the modulation of spectrum width also to increase respectively one, the first sound-optic modulator sweep velocity is at least
The sweep velocity of second, third and fourth sound photomodulator is 10k-100kHz.
Optionally, also comprise in the described optical path adjusting equipment of this device: be arranged at respectively before and after described acousto-optic modulator, for the first convex lens and second convex lens of laser focusing bundle.
Based on above-mentioned purpose, the invention allows for the system of removing Zeeman cooling window deposition in a kind of strontium atom light clock, described device above arranging in this system.
Optionally, the described irradiation light of this system irradiates to the window that zone described Magneto-Optical Trap entrance is used as two-dimensional collimation by described strontium atom light clock system at the emission port from described atomic pile; Pair of windows is opened in the zone exported between described Zeeman cooling window from described Magneto-Optical Trap in described strontium atom light clock system, and described irradiation light irradiates so that atom finally can't arrive the Zeeman cooling window by institute's windowing.
As can be seen from above, in strontium atom light clock provided by the invention, remove the methods, devices and systems of atom in Zeeman cooling window deposition, by illumination, make atom produce transverse velocity, finally can not reach the Zeeman cooling window, this scheme can effectively be removed atom light clock system Atom in Zeeman cooling window deposition on glass, in experiment the irradiating laser live width is below 2M, and the result obtained is can no longer deposit more than 75% atom, makes window glass keep high logical light rate.And this scheme is simple effectively, applying flexible, does not affect the normal operation of strontium atom light clock.
The accompanying drawing explanation
Fig. 1 is prior art light clock system architecture schematic diagram;
Fig. 2 removes atom at Zeeman cooling window deposition process schematic diagram in embodiment of the present invention light clock;
Fig. 3 is
88Sr,
87Sr and
86Tri-kinds of isotopic level structure schematic diagram of Sr;
Fig. 4 is
88Sr and
87Sr atomic transition probability is than the variation schematic diagram with the laser frequency spectrum half-breadth;
Fig. 5 removes the system architecture schematic diagram of atom in Zeeman cooling window deposition in embodiment of the present invention light clock.
Embodiment
For making the purpose, technical solutions and advantages of the present invention clearer, below in conjunction with specific embodiment, and with reference to accompanying drawing, the present invention is described in more detail.
Generally, atom all is on the ground state of low-lying level, and when inciding photon on atom and atomic resonance, atom will absorb photon generation transition, transits to high level by low-lying level.If the upper energy level after atomic transition is not stable state, photon of atom meeting radiation, get back to lower energy level so.The frequency of atom spontaneous radiation photon is certain, and the exit direction of photon is random.After absorption-radiative process, the speed of atom just has certain variation so.
Movement velocity is the atom of V, and momentum is
Photon resonance, follow the law of conservation of momentum after absorbing photon, so the velocity variations of atom
Wherein m is the quality of atom.Atom spontaneous radiation again goes out a photon, and the momentum size of photon is still
But its direction is random, therefore from total statistics, the movement velocity of atom remains and has changed
And be to change on direction of illumination.
When with a branch of resonance irradiation atom the time, photon transition of Atomic absorption is to high level, and then photon of spontaneous radiation falls back to low-lying level.This process can cause the variation of atomic velocity, comprises the direction of motion and the size of speed.
Therefore, thinking of the present invention be at the emission port from described atomic pile except described Magneto-Optical Trap at least one zone described Zeeman cooling window, with the resonance light of atom to be removed along with strontium atom Shu Fangxiang (being atomic beam direction of motion), at angle the atomic motion path being irradiated so that atom finally can't arrive the Zeeman cooling window.
Most importantly nature exists in strontium element,
88Sr,
87Sr and
86Sr, account for respectively 83%, 7% and 9.9% of total amount.These three kinds of isotopic energy levels that the present invention can be applied to as shown in Figure 3.Be topmost wherein
88Sr, second is
87Sr, the 3rd is
86Sr.Because
87Sr has nuclear spin, so energy level all also has hyperfine splitting.
In the embodiment of the present invention, on the system of atom light clock, respectively add pair of windows 201 and 202 before and after the MOT district.As shown in Figure 2.Because
87Sr is the atom that light clock finally needs, therefore for preventing
87Sr arrives and is eliminated before the MOT district, and window 201 places before MOT utilize and strontium atom
87The laser of other isotopes resonance irradiates (in figure shown in 1) beyond Sr; Window 202 places behind the MOT district, utilize and the laser of all high abundance isotopes resonance of strontium atom irradiates (in figure shown in 2), or wherein with the laser of wherein a kind of high abundance isotope resonance, irradiate also passable, be effect slightly almost.The all high abundance isotopes of wherein said strontium atom mainly comprise:
88Sr,
87Sr and
86Sr.Make atom that a horizontal speed be arranged, finally can not arrive the Zeeman cooling window 105 of the rightmost side, thereby remove the deposition of strontium atom on Zeeman cooling window 105.Wherein, described two pairs of windows 201 and 202, can open along the parallel direction of the system table top of atom light clock, also can be along with described table top vertical direction, opening, perhaps other directions open all can, the irradiation light that sees through window as long as make can be walked crosswise speed to one of atomic beam.In addition, also can arrange several to window more, when making atomic beam is irradiated along a direction, also from other positions, simultaneously atomic beam is irradiated, perhaps from other angles, simultaneously atomic beam is irradiated, perhaps above array mode, key are that the beam direction irradiated does not get final product on the contrary, and the angle between best illumination beam is less than or equal to 90 and spends.
Due to the window 106 existed in the light clock system as two-dimensional collimation, so, in the preferred embodiment of the present invention, can directly utilize this to window 106, to be used as that pair of windows 201 before the MOT district.In addition, with and
88Front window 201 places, Guang Zai MOT district and the atomic beam direction vertical incidence of the resonance of Sr element; And with and
87Sr and
86Sr and
88Rear hatch 202 places, Guang Zai MOT district and the atomic beam vertical incidence of the resonance of Sr element.
According to above preferred embodiment, in the situation that along atomic beam direction vertical incidence, if the length from irradiation light incidence window to the Zeeman cooling window is L, Zeeman cooling window radius is R, atomic beam longitudinal velocity V, transverse velocity should be that VR/L just can make atom depart from not arrive the Zeeman window at least.The velocity variations of a photon of the every absorption-radiation of atom is about
Wherein
For Planck's constant, m is atomic mass, and k is the photon wave vector, so each atom need to absorb photon number and is:
The transition probability of atom is τ=2.1 * 10
8/ s, in the situation that the unsaturation light intensity, transition probability is
Wherein Γ is the natural width of atomic transition, and Δ f is frequency offset, and S is the ratio of actual light intensity and saturated light intensity, namely
Strontium atom is 43mW/cm in the saturated light intensity of this transition
2.Therefore in the situation that resonance, irradiating the action length (this action length general corresponding width that irradiate light light beam) of light on the atomic beam direction should be at least:
Rice.
Because
88Sr and
87Two kinds of isotopic 460.862nm transition natural width 32MHz of Sr, the isotope frequency displacement is the 46MHz left and right.In actual applications, the atom in atomic beam can have transverse velocity, and its horizontal speed has a broadening to the frequency spectrum of Atomic absorption photon, is called Doppler broadening.Therefore the incident light spectrum width at window 201 places before the MOT district can not be too wide can not be too narrow.Can make transverse velocity is good lower than the atom continuation absorption photon of VR/L.According to the Doppler broadening formula, transverse velocity is that the atom Doppler broadening of VR/L is Rc/L, and namely incident light spectrum width is best in this magnitude.Consider simultaneously
88Sr and
87Two kinds of isotopic isotope frequency displacements of Sr are less, can and
88The frequency of Sr resonance also may with
87The Sr atomic resonance, therefore should allow
88The Sr atom and
87The probability of Sr Atomic absorption photon transition is than maximum.
Do not consider
88Sr and
87The difference of Sr absorption line shape, when the laser frequency correspondence
88The frequency offset of the resonant frequency of Sr element is from-Δ f to Δ f the time,
88Sr and
87The probability ratio that Sr absorbs photon transition is:
Wherein, x is frequency detuning.When following formula is got peaked the time, best results.When Fig. 4 had shown S=0.1, S=0.5 and S=1, the atomic transition probability was with the variation (three curves in Fig. 4 are followed successively by S=0.1, S=0.5 and S=1 from top to bottom) of laser frequency spectrum width.Generally, for window 201, the spectrum width of getting irradiating laser is 10MHz the best, and centre wavelength is 460.862nm.
But common laser linewidth, below 5MHz, in order to address this problem, can adopt two or multi-laser more.But, in the present embodiment, preferably adopt the method that acousto-optic modulator adjusting line width is set to make the laser frequency spectrum width reach 10MHz.In addition, also can regulate the laser frequency spectrum width by the method for regulating laser current or piezoelectric ceramics makes it reach 10MHz.But need simultaneously to increase, irradiate the action length of light to atom, the action length finally needed is original
Doubly, namely
Wherein LW is laser linewidth (MHz of also take is unit).For guaranteeing that atom can absorb corresponding photon, must make atom cross one-period in the interscan during this period of time of flying over action length, that is to say sweep velocity must faster than
Wherein, utilize the method for acousto-optic modulator modulated laser spectrum width specifically to comprise: on the local oscillation signal of acousto-optic driver, to add that a speed is at least
Modulation signal, depth of modulation is different and different with actuator voltage/frequency variation curve, can make the variation of laser frequency reach 10MHz and get final product.
Optionally, can also utilize the method for regulating electric current and piezoelectric ceramics.By regulating laser current method modulated laser spectrum width, specifically comprise: on laser current, add that a speed is at least
Modulation signal, depth of modulation is different and different with the electric current of laser diode current/frequency variation curve, can make the variation of laser frequency reach 10MHz and get final product.The method modulated laser spectrum width of described adjusting piezoelectric ceramics specifically comprises: add that a speed is at least on the piezoelectric ceramics of controlling laser chamber length
Modulation signal, depth of modulation is different with the characteristic of piezoelectric ceramics, can make the variation of laser frequency reach 10MHz and get final product.
Window 202 places after MOT are with the irradiation of another frequency, because this is behind the MOT zone, the atom herein existed is all useless atom, therefore need not avoid again and other isotope resonance, and can the while and remaining
88Sr and some
86Sr resonance is more thorough in the hope of removing.
88Sr and
86The isotope shift of Sr is the 124MHz left and right,
88Sr and
87The isotope shift of Sr is the 46MHz left and right.Can adopt multi-station laser to be used in combination, but can cause larger waste, therefore preferably take in the present embodiment the synthetic mode of multi-frequency light beam, centre wavelength is 460.862nm.In fact irradiating more accurately center wavelength of light here should be slightly larger with respect to the 460.862nm of the window 201 before the MOT district, but, because difference is very little, numerically is not reflected, and therefore still is similar to wavelength centered by this value here.More accurate wavelength value can access by effect in application, such as the resonance laser fine tuning of front window can be imprisoned in MOT
88The Sr atom, then the regulating action laser frequency, to MOT signal minimum, just think that now laser frequency is
88The resonant frequency of Sr, be the needed frequency of the present embodiment.
Because the major part of atom herein is the low speed atom, therefore be that sweep velocity or the action length of laser on the atomic beam direction do not need too strict, action length can be calculated by this formula:
Wherein V ' is atomic velocity herein, and L ' is the distance that arrives from here the Zeeman cooling window.General preferred action length be scope from 5mm to 20mm, typical effect length gets final product at 10mm.
Based on said method, in a kind of strontium atom light clock system that the present invention proposes, remove the device of atom in Zeeman cooling window deposition, mainly comprise: laser instrument, be used to sending the laser with atomic resonance to be removed; And optical path adjusting equipment, for making the laser that laser instrument sends can be at the emission port from described atomic pile except described Magneto-Optical Trap at least one zone described Zeeman cooling window, edge be irradiated so that atom finally can't arrive the Zeeman cooling window the atomic motion path at angle with the direction of strontium atom Shu Yundong.
In the preferred embodiment of the present invention, can produce laser and adopt four acousto-optic modulators to modulate laser frequency with a laser instrument, to meet above-mentioned requirements.
For example: in light path, with a half-wave plate (λ/2) and polarization spectroscope (PBS) light splitting, a part is for inciding the window 201 before MOT, and another part is for inciding the window 202 after MOT.Incide the light beam of the window 201 before MOT, by first sound-optic modulator, adjust the frequency of laser instrument Output of laser, make laser center frequency after first sound-optic modulator just in time corresponding to strontium element
88The transition of Sr, namely wavelength is the frequency that 460.862nm is corresponding.Now, the centre frequency be used to the first sound CD-ROM driver that drives first sound-optic modulator should be strontium element
88The transition of Sr and laser instrument output frequency poor.Another part light light beam that incides the window 202 after MOT is divided into three beams by one group of half-wave plate (λ/2) and polarization spectroscope (PBS) again, pass through respectively second, third, fourth sound photomodulator.For the centre frequency of second sound CD-ROM driver that drives second sound-optic modulator, should be
86Sr jump frequency and laser output power poor be used to the centre frequency of the 3rd acousto-optic driver that drives the 3rd acousto-optic modulator should be
87Sr jump frequency and laser output power poor be used to the centre frequency of the fourth sound CD-ROM driver that drives fourth sound photomodulator should be
88The transition of Sr and laser instrument output frequency poor.So just realized realizing repertoire with a laser instrument.
Each acousto-optic drives like this can certain choice, unnecessaryly is defined in several isotopic frequency displacements.100MHz above acousto-optic modulator and driver can be chosen in, the spectrum width of 10MHz can be modulated to more easily like this.But want the modulation spectrum width, need each driver to modulate, modulation width 10MHz, modulating speed 10k-100kHz.
If the beam radius of laser is improper, can add in the position of needs suitable lens and laser beam is expanded or compress, make beam radius meet the requirements of size.
Fig. 5 is that the embodiment of the present invention is with removing the strontium atom light clock system architecture schematic diagram of atom at the window precipitation equipment.In Fig. 5, the first half is strontium light clock system body part, and the latter half, for removing the light path part of atom at the window precipitation equipment, comprising: laser instrument 501, half-wave plate (λ/2) 502,512,518,524,531 and 534.Polarization spectroscope (PBS) 503,513,519,532 and 535.Convex lens L1 504 and L2 505, L5 514 and L6515, L7 520 and L8 521 and L9 526 and L10 527.Acousto-optic modulator (AOM) 506,516,522 and 528.Acousto-optic driver 507,517,523 and 529.Convex lens L3508, L4 509, L11 536, L12 537 and catoptron 510,511,525,530,533 and 538.
In the present embodiment strontium atom light clock, remove atom in the device of window deposition:
Laser instrument 501, produce the 460.862nm wavelength laser, can go out this wavelength laser and get final product.
Half-wave plate 502, rotate laser polarization direction, requires the 460.862nm half-wave plate.
When polarization spectroscope (PBS) 503, laser beam arrived, the light of a polarization direction can see through, and incided the window 202 behind the MOT district as rear irradiation light; And vertically the light of this polarization direction can be reflected, incide the window 201 before the MOT district as front irradiation light.Perhaps opposite, i.e. window 201 before the transmitted light of polarization spectroscope 503 incides the MOT district as front irradiation light, reflected light incides the window 202 behind the MOT district as rear irradiation light.Polarization spectroscope 503 and half-wave plate 502 are used in conjunction with, and regulate half-wave plate 502, can regulate seeing through and catoptrical size of polarization spectroscope 503, and requirement can be at the laser wavelength range polarization spectro.
First, second, third and fourth sound photomodulator (AOM) 506,516,522 and 528, the centre frequency of light is increased or reduces a fixed value, this value is decided by acousto-optic driver 507,517,523 and 529 separately, requires the centre frequency of acousto-optic modulator more than 100MHz.
First sound CD-ROM driver 507, as the automatically controlled part of first sound-optic modulator 506, drive the signal center frequency correspondence
88Sr jump frequency and laser instrument output frequency are poor, add simultaneously a modulation, modulation range 10MHz, and sweep velocity is at least
Like this, by the later laser center frequency of acousto-optic modulator 506 corresponding to
88The Sr jump frequency, and, as center, change in the scope of 10MHz, the speed of variation is
Second sound CD-ROM driver 517, as the automatically controlled part of second sound-optic modulator 516, drive the signal center frequency correspondence
86Sr jump frequency and laser instrument output frequency are poor, add simultaneously a modulation, modulation range 10MHz, and sweep velocity is 10k-100kHz.
The 3rd acousto-optic driver 523, as the automatically controlled part of the 3rd acousto-optic modulator 522, drive the signal center frequency correspondence
87Sr jump frequency and laser instrument output frequency are poor, add simultaneously a modulation, modulation range 10MHz, and sweep velocity is 10k-100kHz.
Fourth sound CD-ROM driver 529, as the automatically controlled part of fourth sound photomodulator 528, drive the signal center frequency correspondence
88Sr jump frequency and laser instrument output frequency are poor, add simultaneously a modulation, modulation range 10MHz, and sweep velocity is 10k-100kHz.
Just for example, those skilled in the art also should be able to expect other replacement schemes on this basis to structure shown in Figure 5, such as:
Optionally, first sound CD-ROM driver 507 is not carried out the spectrum width modulation.Can greatly simplify light path like this.But effect is not so good as the good of modulation spectrum.
Optionally, second, third does not modulate spectrum width with fourth sound CD-ROM driver 517,523,529.Because now respectively restraint laser frequency each isotopic resonant frequency of corresponding strontium element respectively, therefore also can modulate.Although effect is not good like this, convenient realization.
Optionally, second sound CD-ROM driver 517 centre frequencies equal
88Sr and
86The isotope frequency displacement of Sr (be about-124MHz); The centre frequency of the 3rd acousto-optic driver 523 equals
88Sr and
87The isotope frequency displacement of Sr (be about-46MHz).In addition, fourth sound photomodulator 528 and driver 529 can save, by first sound-optic modulator 506 and acousto-optic driver 507, realize the function of looking for resonant frequency, now first sound-optic modulator and acousto-optic driver should be placed between wave plate 502 and laser instrument 501.In this case, in fact after first sound-optic modulator 506 modulation, incident arrives in the light beam of second sound-optic modulator and the 3rd acousto-optic modulator the modulation with 10MHz, but be subject to second, the 3rd acousto-optic driver 517, the restriction that 523 centre frequency is too low, from second, the 3rd acousto-optic modulator 516, the light of 522 outputs can not be modulated to the 10MHz width, can't realize the spectrum width modulation of desired 10MHz, therefore at this moment can select to reduce or stop the modulation of first sound CD-ROM driver, so finally from second, the 3rd acousto-optic modulator 516, the very little or not modulation of the Laser Modulation of 522 outputs.
The centre frequency of above-mentioned second, third and fourth sound photomodulator also can be exchanged each other.
Can certainly directly with multi-station laser, realize, save described acousto-optic modulator and driver, but just cause like that the waste of resource.
In addition, also can come separately or synthetic light beam with additive method, as with unpolarized spectroscope (BS).First sound-optic modulator, also can be because of by other laser modulation method, removing.If the light beam that laser instrument 501 sends is enough thick, also beam expanding lens convex lens L3 508 and L4 509 can be set, L11 536 and L12 537.If the laser Laser Output Beam is enough little, also can be without convex lens L1 504 and L2 505, L5 514 and L6 515, L7 520 and L8 521 and L9 526 and L10 527.If it is enough wide that laser instrument 501 sends the live width of laser, also can not adopt scan mode.Two or more laser instrument perhaps also can be set, and the laser that one or more laser instrument send incides MOT forefoot area (can be from a window incident, also can from a plurality of window incident) as front irradiation light, the laser that remaining one or more laser instrument send incides the MOT rear region as rear irradiation light (can be from a window incident, also can be from a plurality of window incident), such shortcoming is to need more laser instrument to increase cost, but other optical device have also been saved, such as: light-dividing device (polarization spectroscope 503, 513 and 519, and the half-wave plate 502 be used in conjunction with, 512 and 518 catoptrons 510, 511 and 525 etc.), laser frequency regulating device (convex lens L1 504, L2 505, L5 514, L6 515, L7 520 and L8 521 and L9 526 and L10 527, acousto-optic modulator 506, 516, 522 and 528, acousto-optic driver 507, 517, 523 and 529), parallel beam expand device (convex lens L3 508 and L4509 even, L11 536 and L12 537) etc., help to reduce device volume.
Optionally, here also can directly modulate the laser that incides the MOT rear hatch by the mode of scanning, make all high abundance isotopes of its frequency coverage, the centre frequency of the acousto-optic modulator but needed like this should be more than 1G, and guarantee can scan the 100MHz width.Because the acousto-optic modulator efficiency of 1GHz centre frequency is very low, this kind method can cause the significant wastage of laser power.But this method has been saved the optics adjustment part, if in figure, omitted be used to distributing the optical path adjusting device of light path: devices such as half-wave plate 512, PBS 513 and half-wave plate 518, PBS 519, convex lens L7 520, L8 521, acousto-optic modulator 522 and 528, acousto-optic driver 523 and 529, catoptron 525, catoptron 526, half-wave plate 527, PBS 528, catoptron 529, half-wave plate 531, PBS 532.
In addition, described irradiation light direction is also not necessarily vertical with the atomic beam direction, also can become other angles.For increasing effect, illumination beam also can be more.Illumination beam also is not limited to all in the mode of directional light, in the same direction atomic beam direction of motion be irradiated, needs according to actual conditions, each bundle irradiates can be at angle between light, such as a branch of light parallel with atom light clock table top, at the same area or zones of different, atomic beam direction of motion is irradiated simultaneously with a branch of light vertical with table top.
In a word, above-described specific embodiment is only specific embodiments of the invention, is not limited to the present invention.Within the spirit and principles in the present invention all, any modification of making, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.
Claims (23)
1. in a strontium atom light clock system, remove the method for atom in Zeeman cooling window deposition, in described strontium atom light clock system, on the atomic beam direction, be in line and be laid with successively be used to the atomic pile of launching atomic beam, for Magneto-Optical Trap and the Zeeman cooling window of Trapping of Atoms, it is characterized in that
At the emission port from described atomic pile except described Magneto-Optical Trap, at least one zone described Zeeman cooling window, use with the laser of atomic resonance to be removed and along an angle, the atomic beam motion path is irradiated so that atom finally can't arrive the Zeeman cooling window.
2. method according to claim 1, it is characterized in that, if described laser more than a branch of, each Shu Jiguang irradiates in the same direction at diverse location, perhaps at diverse location, irradiate along different but non-opposite direction, or irradiate along different but non-opposite direction at same position.
3. method according to claim 1, is characterized in that, described laser irradiates by the window that is used as two-dimensional collimation in described strontium atom light clock system.
4. method according to claim 1, is characterized in that, when the zone of irradiating be from the emission port of described atomic pile to described Magneto-Optical Trap entrance the time, described laser be with
87The laser of other isotope resonance beyond Sr; When from described Magneto-Optical Trap, exporting between described Zeeman cooling window, described laser be the laser with all high abundance isotopes resonance of strontium atom when the zone of described irradiation, or the laser that resonates of a kind of high abundance isotope wherein.
5. method according to claim 4, is characterized in that, described with
87Beyond Sr the laser of other isotopes resonance be with
88The laser of Sr isotope resonance; The laser of all high abundance isotopes resonance of described and strontium atom be with
87Sr and
86Sr and
88The laser of Sr resonance.
6. according to the described method of claim 1-5 any one, it is characterized in that, the zone of irradiating is: from the emission port of described atomic pile to described Magneto-Optical Trap entrance, and export between described Zeeman cooling window and simultaneously the atomic motion path is irradiated from described Magneto-Optical Trap.
7. method according to claim 6, is characterized in that, described Ear Mucosa Treated by He Ne Laser Irradiation direction is vertical with the direction of strontium atom Shu Yundong.
8. method according to claim 7, is characterized in that,
When the zone of described irradiation be from the emission port of described atomic pile to described Magneto-Optical Trap entrance the time, the centre wavelength of described laser is 460.862nm, line width or sweep length are 10MHz;
When the zone of described irradiation is that while from described Magneto-Optical Trap, exporting between described Zeeman cooling window, the centre wavelength of described laser is 460.862nm, the line width of described laser or sweep length are 100,000,000 magnitudes.
9. method according to claim 8, is characterized in that, when the zone of described irradiation be from the emission port of described atomic pile to described Magneto-Optical Trap entrance the time, described Laser emission adopts scan mode, sweep limit 10MHz, sweep velocity is at least
Wherein, V is the atomic beam longitudinal velocity, and R is Zeeman cooling window radius, and m is atomic mass, and S is the ratio of actual light intensity and saturated light intensity, and τ is the transition probability of atom, and k is the photon wave vector,
For Planck's constant, L is for irradiating the length of light incidence window to the Zeeman cooling window, LW laser linewidth;
When the zone of described irradiation is while from described Magneto-Optical Trap, exporting between described Zeeman cooling window, described Laser emission adopts multi-frequency light beam synthesis mode.
10. method according to claim 8, is characterized in that, when the zone of described irradiation be from the emission port of described atomic pile to described Magneto-Optical Trap entrance the time, the action length of described laser on the atomic beam direction is at least
Rice, wherein, V is the atomic beam longitudinal velocity, and R is Zeeman cooling window radius, and m is atomic mass, and S is the ratio of actual light intensity and saturated light intensity, and τ is the transition probability of atom, and k is the photon wave vector,
For Planck's constant, L is for irradiating the length of light incidence window to the Zeeman cooling window, LW laser linewidth;
When the zone of described irradiation is that while from described Magneto-Optical Trap, exporting between described Zeeman cooling window, the action length of described laser on the atomic beam direction is
Wherein V ' is atomic velocity herein, and L ' is the distance that arrives from here the Zeeman cooling window, and R is Zeeman cooling window radius, and m is atomic mass, and S is the ratio of actual light intensity and saturated light intensity, and τ is the transition probability of atom, and k is the photon wave vector,
For Planck's constant, the LW laser linewidth.
11. method according to claim 10, is characterized in that, irradiating light is that 5mm is between 20mm in the action length scope on the atomic beam direction.
12. in a strontium atom light clock system, remove the device of atom in the window deposition, in described strontium atom light clock system, on the atomic beam direction, be in line and be laid with successively be used to the atomic pile of launching atomic beam, for Magneto-Optical Trap and the Zeeman cooling window of Trapping of Atoms, it is characterized in that, this device comprises:
Laser instrument, be used to sending the laser with atomic resonance to be removed; And
Optical path adjusting equipment, for the laser that laser instrument sends can, at the emission port from described atomic pile except described Magneto-Optical Trap at least one zone described Zeeman cooling window, be irradiated so that atom finally can't arrive the Zeeman cooling window the atomic motion path along an angle.
13. device according to claim 12, is characterized in that, described optical path adjusting equipment also comprises: parallel beam expand device expands for the laser beam that laser instrument is sent.
14. device according to claim 13, it is characterized in that, described parallel beam expand device is extender lens pair, and described extender lens for wishing the beam radius obtained and original beam radius ratio, is coated with anti-reflection film on right each lens of described extender lens to the latter and the former's focal distance ratio.
15. device according to claim 12, is characterized in that, also comprises in described optical path adjusting equipment: half-wave plate rotates the laser polarization direction that semiconductor laser sends;
Polarization spectroscope, make through the postrotational laser beam of half-wave plate after polarization spectroscope, part light is reflected, in an irradiation area, described atomic beam motion path is irradiated therein, another part light is transmitted in another irradiation area described atomic beam motion path is irradiated.
16. device according to claim 12, is characterized in that, the optical maser wavelength of described laser instrument emission is 460.862nm.
17. device according to claim 12, is characterized in that, when the zone of irradiating be from the emission port of described atomic pile to described Magneto-Optical Trap entrance the time, described laser be with
87The laser of other isotope resonance beyond Sr; When from described Magneto-Optical Trap, exporting between described Zeeman cooling window, described laser be the laser with all high abundance isotopes resonance of strontium atom when the zone of described irradiation, or the laser that resonates of a kind of high abundance isotope wherein.
18. device according to claim 17, is characterized in that, described with
87Beyond Sr the laser of other isotopes resonance be with
88The laser of Sr isotope resonance; The laser of all high abundance isotopes resonance of described and strontium atom be with
87Sr and
86Sr and
88The laser of Sr resonance.
19. device according to claim 18, is characterized in that, also comprises in described optical path adjusting equipment: first, second, third and fourth sound photomodulator, for the centre frequency by light, increase or reduce a fixed value;
The first sound CD-ROM driver, as the automatically controlled part of first sound-optic modulator, drive the signal center frequency correspondence
88Sr jump frequency and laser instrument output frequency are poor;
Second sound CD-ROM driver, as the automatically controlled part of second sound-optic modulator, drive the signal center frequency correspondence
86Sr jump frequency and laser instrument output frequency are poor;
The 3rd acousto-optic driver, as the automatically controlled part of the 3rd acousto-optic modulator, drive the signal center frequency correspondence
87Sr jump frequency and laser instrument output frequency are poor;
Fourth sound CD-ROM driver, as the automatically controlled part of fourth sound photomodulator, drive the signal center frequency correspondence
88Sr jump frequency and laser instrument output frequency are poor.
20. device according to claim 19, is characterized in that, described first, second, third and fourth sound CD-ROM driver, and modulation range is 10MHz be used to enlarging the modulation of spectrum width also to increase respectively one, the first sound-optic modulator sweep velocity is at least
Wherein, V is the atomic beam longitudinal velocity, and R is Zeeman cooling window radius, and m is atomic mass, and S is the ratio of actual light intensity and saturated light intensity, and τ is the transition probability of atom, and k is the photon wave vector,
For Planck's constant, L is for irradiating the length of light incidence window to the Zeeman cooling window, the LW laser linewidth, and the sweep velocity of second, third and fourth sound photomodulator is 10k-100kHz.
21. device according to claim 19, is characterized in that, also comprises in described optical path adjusting equipment: be arranged at respectively before and after described acousto-optic modulator, for the first convex lens and second convex lens of laser focusing bundle.
22. remove the system that the Zeeman cooling window deposits in a strontium atom light clock, it is characterized in that, the described device of claim 12-21 any one is set in this system.
23. system according to claim 22, is characterized in that, described laser irradiates to the window that zone described Magneto-Optical Trap entrance is used as two-dimensional collimation by described strontium atom light clock system at the emission port from described atomic pile; Pair of windows is opened in the zone exported between described Zeeman cooling window from described Magneto-Optical Trap in described strontium atom light clock system, and described laser irradiates so that atom finally can't arrive the Zeeman cooling window by institute's windowing.
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Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1603984A (en) * | 2004-11-05 | 2005-04-06 | 中国科学院武汉物理与数学研究所 | Coherent arrangement imprisoned cold atomic clock |
CN101145025A (en) * | 2007-09-13 | 2008-03-19 | 中国科学院武汉物理与数学研究所 | Coherent maser radiation cold atomic clock |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU8055391A (en) * | 1990-06-01 | 1991-12-31 | Research Corporation Technologies, Inc. | An improved frequency standard using an atomic stream of optically cooled atoms |
-
2009
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Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1603984A (en) * | 2004-11-05 | 2005-04-06 | 中国科学院武汉物理与数学研究所 | Coherent arrangement imprisoned cold atomic clock |
CN101145025A (en) * | 2007-09-13 | 2008-03-19 | 中国科学院武汉物理与数学研究所 | Coherent maser radiation cold atomic clock |
Non-Patent Citations (2)
Title |
---|
87Sr原子束的塞曼减速器磁场的研究;王心亮 等;《时间频率学报》;20081231;第31卷(第2期);92-97 * |
王心亮 等.87Sr原子束的塞曼减速器磁场的研究.《时间频率学报》.2008,第31卷(第2期),92-97. |
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