A kind of method and apparatus of building filter frequency reflecting mirrorTechnical field
The present invention relates to a kind of method and apparatus of building filter frequency reflecting mirror.
Background technique
Plane mirror is commonly used a kind of optical device in Experiments of Optics, is mainly used for changing the direction of propagation of lightOr light intensity magnitude.According to wave-length coverage, plane mirror can be divided into Single wavelength reflecting mirror and broadband mirrors；According to reflectivitySize can be divided into total reflective mirror, the reflecting mirror of 50/50 beam splitter, anti-reflection mirror and any reflectivity；According to reflection angle, 0 can be divided intoSpend reflecting mirror, 45 degree of reflecting mirrors etc..
Plane mirror in the prior art is mainly by realizing in lens surface plated film, but after plated film, generallyCan only meet a kind of the needs of condition, function is relatively single.For example, a branch of light by total reflective mirror reflection is transformed to semi-transparent semi-reflectingWhen, then it needs for total reflective mirror to be changed to 50/50 beam splitter, it is above-mentioned also to can use the realization of the optical devices such as wave plate and devating prismFunction, but the device count in optical path is increased, adjusting is cumbersome, is unfavorable for the integrated of system.In addition more important point is, oneIn a little experiments, need to select the frequency in light beam, but receive because the plated film precision of traditional optical device can only achieveRice magnitude, frequency can not be selected in the light of order of megahertz, therefore existing optical device does not have frequency screening functionEnergy.Although can use resonant cavity technology carries out frequency selection, it is related to locking the technologies such as chamber, frequency stabilization, system complex, to experimentEnvironmental requirement is harsh, and operation difficulty is larger.
Summary of the invention
Present invention aim to address existing plane mirror do not have frequency screening function, using resonant cavity technology intoLine frequency selects existing system complex and the big technical problem of operation difficulty, provide a kind of building filter frequency reflecting mirror method andEquipment.
In order to solve the above technical problems, the technical scheme adopted by the invention is that: a method of building filter frequency reflecting mirror,Include the following steps:
1) the first polarization splitting prism and second is respectively set at the optical path entrance port of thermokalite metallic atom steam chest two sidesPolarization splitting prism, the setting the at the optical path entrance port of the first polarization splitting prism and any side of the second polarization splitting prismOne 45 ° of total reflective mirrors enable signal light opposing coupler light direction to pass through thermokalite metallic atom vapour with the incident angles less than 0.6 °Room；
2) by two beam frequencies, polarization and the identical coupling light of power respectively through the first polarization splitting prism, the second polarization pointIt is opposite after light refraction by prism collinearly to pass through thermokalite metallic atom steam chest, standing wave is formed in thermokalite metallic atom steam chest；It will be anotherThe signal light of beam frequency consecutive variations opposing coupler light direction after the one 45 ° of total reflective mirror reflects is entered with the incidence angle less than 0.6 °It is shot through overheat alkali metal atom steam chest；Meet two-photon resonance transition conditions when signal light frequency is scanned to the frequency with coupling lightWhen, four-wave mixing effect is generated, while reversely generating the identical four-wave mixing signal light of a branch of frequency, the four-wave mixing signal lightReflection direction with coupling light direction formed angle of reflection and signal light relative to coupling the incidence angle size of light it is identical, direction phaseInstead, the signal light of other incident frequency contents passes through thermokalite metallic atom steam chest along former incident direction, to realize that filter frequency is anti-Penetrate mirror function.
Further, filled with Cs atom steam in the thermokalite metallic atom steam chest；The coupling light is wavelength 894.5nmAnd the laser of continuously-tuning, frequency effect is in Cs atom D1 line ground state Fg=4 to excitation state Fe=4 energy level transition；It is describedSignal light is the laser of wavelength 894.5nm and continuously-tuning, and frequency effect is in Cs atom D1 line ground state Fg=3 to excitation stateFe=4 energy level transition and continuous scanning, coupling light, signal light and Cs atom act on forming the transparent energy level knot of Λ type electromagnetically inducedStructure.
Further, the signal light is 0.43 ° relative to the incidence angle θ of coupling light direction.
It is a kind of using above-mentioned building filter frequency mirror approach equipment, including filter frequency mirror system, signal light system andDetection system；
The filter frequency mirror system includes the first semiconductor laser, the first optoisolator, beam splitter, the first half-wavePiece, the 2nd 45 ° of total reflective mirror, the second half-wave plate and former by the first polarization splitting prism, the second polarization splitting prism, thermokalite metalThe filter frequency reflecting mirror that sub- steam chest and the one 45 ° of total reflective mirror are constituted, the first semiconductor laser are coupling radiant, the first semiconductorIt is successively arranged the first optoisolator and beam splitter on the emitting light path of laser, is successively arranged first in the optical path of beam splitter transmissionHalf-wave plate and the first polarization splitting prism, the optical path of beam splitter reflection are equipped with the 2nd 45 ° of total reflective mirror, the 2nd 45 ° of total reflective mirrorThe second half-wave plate and the second polarization splitting prism, the first polarization splitting prism and the second polarization spectro are successively arranged on reflected light pathThe reflected light path of prism is equipped with thermokalite metallic atom steam chest, and first is arranged at the optical path entrance port of the first polarization splitting prism45 ° of total reflective mirrors enable signal light opposing coupler light direction to pass through thermokalite metallic atom steam chest with the incident angles less than 0.6 °；
The signal light system includes the second semiconductor laser, the second optoisolator, third half-wave plate and third polarizationAmici prism, the second semiconductor laser are signal radiant, and the is arranged in sequence on the emitting light path of the second semiconductor laserTwo optoisolators, third half-wave plate and third polarization splitting prism；
The detection system includes the first photodetector, the second photodetector and digital storage oscilloscope, the first lightElectric explorer, which is located at, reflects and sequentially passes through thermokalite metallic atom steam chest and the second polarization splitting prism through the one 45 ° of total reflective mirrorIn optical path, the second photodetector is located at the optical path for passing back through the four-wave mixing signal reflex light of the first polarization splitting prismOn, the signal output end of the first photodetector and the second photodetector is connected with digital storage oscilloscope jointly.
Further, the equipment further includes temperature controller, and the periphery that the temperature controller is located at thermokalite metallic atom steam chest is usedIn the temperature for controlling and showing thermokalite metallic atom steam chest, the temperature of thermokalite metallic atom steam chest is 30-70 degrees Celsius.
Further, the temperature of the thermokalite metallic atom steam chest is 64 degrees Celsius.
Further, the both ends end face of the thermokalite metallic atom steam chest is coated with the anti-reflection film that relative wavelength is 894.5nm,Wrap up in the μ foil that haves three layers in the side of thermokalite metallic atom steam chest.
Further, the first photodetector and the second photodetector are respectively through the first BNC conducting wire and the 2nd BNC conducting wireIt is connected to digital storage oscilloscope, for showing detectable signal and storing data, the trigger signal of digital storage oscilloscope is by theTwo semiconductor lasers provide.
Further, the reflectivity of the filter frequency reflecting mirror can be adjusted by adjusting the second half-wave plate.
The beneficial effects of the present invention are: can realize that reflectivity is continuously adjustable, reflection efficiency height and width bandwidth through the inventionFilter frequency reflector apparatus, the researchs neck such as which stores in multichannel quantum information, quantum logic door operation and all-optical switchDomain has important application value.
1, the present invention has frequency selection index system: i.e. under the conditions of standing wave couples light, meeting two-photon with light frequency is coupledThe signal light of the frequency of resonance condition can be reflected, and the signal light of other frequency contents then continues to transmit medium, thereforePlay filter frequency selection index system；
2, the reflectivity for the filter frequency reflecting mirror that the present invention constructs being capable of consecutive variations: i.e. by after adjusting to the strong of coupling lightDegree, may be implemented the continuous control to incoming signal light, makes its reflectivity from 0 consecutive variations to maximum；
3, the filter frequency reflecting mirror that the present invention constructs has the reflection efficiency of 40%-60%；
4, apparatus of the present invention core system is simple and compact for structure, is easy to minimize integrated；
5, the system that method of the invention may extend to other light and Three-level Atom interaction.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of present invention filter frequency reflecting mirror；
Fig. 2 is the structural schematic diagram of present device；
In figure: the first semiconductor laser of 1-, the first optoisolator of 2-, 3- beam splitter, the first half-wave plate of 4-, 5- first are inclinedShake Amici prism, the 2nd 45 ° of total reflective mirror of 6-, the second half-wave plate of 7-, the second polarization splitting prism of 8-, 9- thermokalite metallic atom vapourRoom, 10- temperature controller, the second semiconductor laser of 11-, the second optoisolator of 12-, 13- third half-wave plate, 14- third polarization pointLight prism, the one 45 ° of total reflective mirror of 15-, the first photodetector of 16-, the second photodetector of 17-, the first BNC line of 18-, 19-2nd BNC line, 20- digital storage oscilloscope；
Fig. 3 is that light field acts on Cs atom energy level transition schematic diagram in the present invention；
Fig. 4 is the normalized transmitted signal strength spectrogram after the change under coupled field power condition in the present invention；
Fig. 5 is the normalized reflected signal strength spectrogram after the change under coupled field power condition in the present invention；
Fig. 6 is the reflection efficiency of present invention filter frequency reflecting mirror with the trend chart of signal angle of light；
Fig. 7 is the reflection efficiency of present invention filter frequency reflecting mirror with the trend chart of Cs atom steam chest temperature change；
Fig. 8 is the reflection signal spectrogram under different coupling light frequencies are detuning in the present invention.
Specific embodiment
Invention is further explained with reference to the accompanying drawings and examples.
As shown in Figure 1, the method for one of the present embodiment building filter frequency reflecting mirror, includes the following steps:
1) the first polarization splitting prism 5 and are respectively set at the optical path entrance port of 9 two sides of thermokalite metallic atom steam chestTwo polarization splitting prisms 8, at the optical path entrance port of the first polarization splitting prism 5 and any side of the second polarization splitting prism 8The one 45 ° of total reflective mirror 15, which is arranged, enables signal light opposing coupler light direction to pass through thermokalite metal with the incident angles less than 0.6 °Atom steam chest 9；
2) by two beam frequencies, polarization and the identical coupling light of power respectively through the first polarization splitting prism 5, second polarization pointLight prism 8 is opposite after reflecting collinearly to pass through thermokalite metallic atom steam chest 9, forms standing wave in thermokalite metallic atom steam chest 9；It will be anotherThe signal light of a branch of frequency consecutive variations after the one 45 ° of total reflective mirror 15 reflects opposing coupler light direction with the incidence less than 0.6 °Angle incidence passes through thermokalite metallic atom steam chest 9；Meet two-photon resonance jump when signal light frequency is scanned to the frequency with coupling lightWhen moving condition, four-wave mixing effect is generated, while reversely generating the identical four-wave mixing signal light of a branch of frequency, the four-wave mixingThe reflection direction of signal light with coupling light direction formed angle of reflection and signal light relative to coupling the incidence angle size of light it is identical,Contrary, the signal light of other incident frequency contents passes through thermokalite metallic atom steam chest 9 along former incident direction, to realizeFilter frequency mirror function.
As shown in Fig. 2, a kind of equipment using the method for building filter frequency reflecting mirror in above-described embodiment, it is characterised in that:Including filter frequency mirror system, signal light system and detection system；
The filter frequency mirror system includes the first semiconductor laser 1, the first optoisolator 2, beam splitter 3, the first half4, the 2nd 45 ° of total reflective mirrors 6 of wave plate, the second half-wave plate 7 and by the first polarization splitting prism 5, the second polarization splitting prism 8, thermokaliteThe filter frequency reflecting mirror that metallic atom steam chest 9 and the one 45 ° of total reflective mirror 15 are constituted, the first semiconductor laser 1 are coupling radiant,The first optoisolator 2 and beam splitter 3, the optical path that beam splitter 3 transmits are successively arranged on the emitting light path of first semiconductor laser 1On be successively arranged the first half-wave plate 4 and the first polarization splitting prism 5, the optical path that beam splitter 3 reflects is equipped with the 2nd 45 ° of total reflective mirrorThe second half-wave plate 7 and the second polarization splitting prism 8, the first polarization point are successively arranged on the reflected light path of 6, the 2nd 45 ° of total reflective mirror 6The reflected light path of light prism 5 and the second polarization splitting prism 8 is equipped with the thermokalite metallic atom vapour of internal-filling alkali metal atomic mediumRoom 9, the one 45 ° of total reflective mirror 15, which is arranged, at the optical path entrance port of the first polarization splitting prism 5 makes signal light opposing coupler light sideTo can with the incident angles less than 0.6 ° pass through thermokalite metallic atom steam chest 9；
The signal light system includes the second semiconductor laser 11, the second optoisolator 12, third half-wave plate 13 and theThree polarization splitting prisms 14, the second semiconductor laser 11 are signal radiant, the emitting light path of the second semiconductor laser 11On the second optoisolator 12, third half-wave plate 13 and third polarization splitting prism 14 is arranged in sequence；
The detection system includes the first photodetector 16, the second photodetector 17 and digital storage oscilloscope 20,First photodetector 16, which is located at, reflects through the one 45 ° of total reflective mirror 15 and sequentially passes through thermokalite metallic atom steam chest 9 and second partiallyIt shakes in the optical path of Amici prism 8, the second photodetector 17 is located at the four-wave mixing letter for passing back through the first polarization splitting prism 5In the optical path of number reflected light, the signal output end of the first photodetector 16 and the second photodetector 17 is connected with number jointlyStorage oscillograph 20.
The equipment further includes temperature controller 10, and the temperature controller 10 is located at the periphery of thermokalite metallic atom steam chest 9 for controllingThe temperature of system and display thermokalite metallic atom steam chest 9, the temperature of thermokalite metallic atom steam chest 9 are 30-70 degrees Celsius.
Embodiment 1
1) method of one of the present embodiment building filter frequency reflecting mirror, includes the following steps: filled with Cs atom steam9 two sides of thermokalite metallic atom steam chest optical path entrance port at the first polarization splitting prism 5 and the second polarization spectro is respectively setThe one 45 ° of total reflective mirror 15 is arranged in prism 8 at the optical path entrance port of the first polarization splitting prism 5, adjusts the one 45 ° of total reflective mirror15 enable signal light opposing coupler light direction to pass through thermokalite metallic atom steam chest 9 with 0.43 ° of incident angles；2) by two beams frequencyRate is identical with polarization, the coupling light of 20 milliwatt of power, wavelength 894.5nm and continuously-tuning is respectively through the first polarization splitting prism5, opposite after the reflection of the second polarization splitting prism 8 collinearly to pass through thermokalite metallic atom steam chest 9, two beams couple the frequency effect of light inCs atom D1 line ground state Fg=4 to excitation state Fe=4 energy level transition forms standing wave in thermokalite metallic atom steam chest 9；It will be anotherA branch of frequency consecutive variations, 300 microwatt of power, wavelength 894.5nm and continuously-tuning signal light through the one 45 ° of total reflective mirror 15Opposing coupler light direction passes through thermokalite metallic atom steam chest 9, the frequency effect of signal light with 0.43 ° of incident angles after refractionIn Cs atom D1 line ground state Fg=3 to excitation state Fe=4 energy level transition and continuous scanning, in coupling light, signal light and Cs atomThe transparent level structure of Λ type electromagnetically induced is formed under effect；Meet two-photon when signal light frequency is scanned to the frequency with coupling lightWhen resonant transition condition, four-wave mixing effect is generated, while reversely generating the identical four-wave mixing signal light of a branch of frequency, this fourThe reflection direction of wave mixing signal light is big relative to the incidence angle of coupling light with the angle of reflection and signal light for coupling light direction formationSmall identical, contrary, the signal light of other incident frequency contents passes through thermokalite metallic atom steam chest 9 along former incident direction,To realize filter frequency mirror function.
Use the above-mentioned equipment for applying building filter frequency mirror approach in example, including filter frequency mirror system, signal light systemAnd detection system；
The filter frequency mirror system includes the first semiconductor laser 1, the first optoisolator 2,50/50 beam splitter 3, the4, the 2nd 45 ° of total reflective mirrors 6 of half of wave plate, the second half-wave plate 7, temperature controller 10 and by the first polarization splitting prism 5, second polarization pointThe filter frequency reflecting mirror that light prism 8, thermokalite metallic atom steam chest 9 and the one 45 ° of total reflective mirror 15 are constituted, use output wavelength forThe first semiconductor laser 1 conduct coupling radiant of 894.5nm, frequency continuously-tuning, the first semiconductor laser 1 go outIt penetrates in optical path and is successively arranged the first beam splitter of optoisolator 2 and 50,/50 3, couple light through the first beam splitting of optoisolator 2 and 50/50It is divided into the identical two-beam of power after device 3, the first half-wave plate 4 and the first polarization point is successively arranged in the optical path that beam splitter 3 transmitsLight prism 5, the optical path that beam splitter 3 reflects are equipped with the 2nd 45 ° of total reflective mirror 6, simultaneously through 50/50 beam splitter 3 and the first half-wave plate 4Coupling light through the reflection of the first polarization splitting prism 5 is preceding to coupling light, the light reflected through beam splitter 3 be after to coupling light,Backward coupling optical path is equipped with the 2nd 45 ° of total reflective mirror 6, is successively arranged the second half-wave plate on the reflected light path of the 2nd 45 ° of total reflective mirror 67 and second polarization splitting prism 8, the reflected light path of the first polarization splitting prism 5 and the second polarization splitting prism 8 is equipped with interior fillThe thermokalite metallic atom steam chest 9 of Cs atom medium is equipped with temperature controller 10 in the periphery of thermokalite metallic atom steam chest 9；Forward direction couplingLight and backward coupling light are all from the first semiconductor laser 1, therefore two-beam frequency is identical, and polarization direction is identical, passes through tuneThe first half-wave plate 4 and the second half-wave plate 7 are saved, keeps the power of two-beam identical, i.e. Pc2=Pc1=20 milliwatts, two-beam are superimposed shapeAt standing wave coupled field；The one 45 ° of total reflective mirror 15 is arranged at the optical path entrance port of the first polarization splitting prism 5 keeps signal light oppositeThermokalite metallic atom steam chest 9 can be passed through with 0.43 ° of incident angles by coupling light direction；
The signal light system includes the second semiconductor laser 11, two optoisolators 12, third half-wave plate 13 and thirdPolarization splitting prism 14, using output wavelength is the second semiconductor laser 11 of 894.5nm, frequency continuously-tuning as letterThe second optoisolator 12,13 and of third half-wave plate is arranged in sequence on the emitting light path of the second semiconductor laser 11 in number radiantThird polarization splitting prism 14；The light that second semiconductor laser 11 issues passes through the second optoisolator 12, third half-wave plate 13With third polarization splitting prism 14, the light of the horizontal polarization transmitted through third polarization splitting prism 14 passes through tune as signal lightSection third half-wave plate 13 makes the power P of signal lights=300 microwatts；Made by adjusting the one 45 ° of total reflective mirror 15 across the first polarizationThe signal light of Amici prism 5 enters thermokalite metallic atom steam chest 9 relative to coupling light direction with 0.43 ° of incidence angle, and fromSecond polarization splitting prism 8 is transmitted into the first photodetector 16；
The detection system includes the first photodetector 16, the second photodetector 17 and digital storage oscilloscope 20；First photodetector 16, which is located at, reflects through the one 45 ° of total reflective mirror 15 and sequentially passes through thermokalite metallic atom steam chest 9 and second partiallyIt shaking in the optical path of Amici prism 8, the first 16 pairs of photodetector is detected through the signal light of thermokalite metallic atom steam chest 9,The frequency detuning Δ of the coupling light issued through the first semiconductor laser is also monitored simultaneouslyc；Second photodetector 17 is located at insteadTo in the optical path for the four-wave mixing signal reflex light for passing through the first polarization splitting prism 5, for detecting the four-wave mixing letter of reflectionNumber intensity variation detuning with signal light frequency；The signal output end of first photodetector 16 and the second photodetector 17 pointNot Tong Guo the first BNC line 18 and the 2nd BNC line 19 be connected to the signal input part of digital storage oscilloscope 20, two photodetectionsDevice is direct current detector, and performance parameter is identical, and the signal detected passes through BNC conducting wire input stored digital respectively and showsIt is shown in wave device 20 and acquires data, the trigger signal of digital storage oscilloscope 20 is provided by the second semiconductor laser 11.
In the present embodiment, the length of thermokalite metallic atom steam chest 9 is 75mm, at the both ends end of thermokalite metallic atom steam chest 9Face is coated with the anti-reflection film that wavelength is 894.5nm, can reduce transmission and reflection signal light is generated when passing through steam chest by glass surfaceReflection loss, while wrapping up in the μ foil that haves three layers in the side of thermokalite metallic atom steam chest 9, maskable external magnetic field is to medium in steam chestThe influence of energy level；The temperature of thermokalite metallic atom steam chest 9 is 64 degrees Celsius.
Fig. 3 is the schematic diagram that light field acts on Cs atom energy level transition.In figure, forward direction couples optical frequencyc1With backward couplingLight combination frequencies omegac2It is identical, i.e. ωc1=ωc2, the Frequency Locking of light is coupled in Cs atom D1 line ground state 6 by two2S1/2, Fg=4To excitation state 62P1/2, FeNear=4 energy level transition, the frequency detuning of coupling light relative atom resonance centre is Δc, Δc=ωc1-ω44, ω44For Cs atom energy level Fg=4 arrive Fe=4 jump frequency；Signal light frequency is in Cs atom D1 line ground state62S1/2, Fg=3 to excitation state 62P1/2, Fe=4 resonance centre scanning, the frequency detuning of signal light relative atom resonance centreFor Δs, Δs=ωs-ω34, ω34For Cs atom energy level Fg=3 arrive Fe=4 jump frequency, signal light and coupling light and atomInteraction, forms the transparent level structure of Λ type three-level electromagnetically induced.
Fig. 4 is under conditions of the present embodiment, and when after change to coupled optical power, the normalization transmission signal of signal light is strongSpend spectrogram.In figure: (1) to coupled optical power P after beingc2When=0, the normalization transmitted signal strength T of signal light is with signal optical frequencyThe detuning Δ of ratesChange curve；(2) to coupled optical power half, i.e. P before being equal to after being to coupled optical powerc2=0.5Pc1When,The normalization transmitted signal strength T of signal light is with the detuning Δ of signal light frequencysChange curve；(3) to coupled optical power after beingEqual to preceding to coupled optical power, i.e. Pc2=Pc1When, the normalization transmitted signal strength T of signal light is with the detuning Δ of signal light frequencysChange curve；The normalization transmitted signal strength T=of signal light detects transmission signal light intensity through the first photodetector 16The signal light intensity of Cs atom steam chest 9 spend/is reflected into through the one 45 ° of reflecting mirror 15；Signal light frequency is in Cs atom D1 line baseState 62S1/2, Fg=3 to excitation state 62P1/2, Fe=4 energy level transition immediate vicinity scanning；By adjusting the second semiconductor laserThe voltage of device 11 makes the detuning Δ of signal light frequencysWhen=0, there is peak value in (1), (2) and (3) curve in Fig. 4, peak in (1)Value is maximum, to coupled optical power P after explanationc2When=0, the signal light of transmission is most, and (3) are negative peak, illustrates Pc2=Pc1When, thoroughlyThe signal light penetrated is minimum.
Fig. 5 is that on the basis of fig. 4, to coupled field power condition after change, the normalization of four-wave mixing signal light is reflectedSignal strength spectrum.In figure: (1) to coupled optical power P after beingc2When=0, the normalization reflected signal strength of four-wave mixing signal lightR is with the detuning Δ of signal light frequencysChange curve；(2) to coupled optical power P after beingc2=0.5Pc1When, four-wave mixing signal lightNormalization reflected signal strength R with the detuning Δ of signal light frequencysChange curve；(3) to coupled optical power P after beingc2=Pc1When, the normalization reflected signal strength R of four-wave mixing signal light is with the detuning Δ of signal light frequencysChange curve；Four-wave mixingThe reflection for the four-wave mixing signal light that the normalization reflected signal strength R=of signal light is detected through the second photodetector 17 is believedThe signal light intensity of number intensity/be reflected into through the one 45 ° of reflecting mirror 15 Cs atom steam chest 9.As shown in Figure 5, when after to couplingOptical power Pc2When=0, incident signal light transmits from Cs atom steam chest 9 and is gone out, and generates at this time without four-wave mixing reflection signal, formerSub- medium system is transparent for the signal light that frequency meets two-photon resonance；The second half-wave plate 7 is adjusted, to coupling light after makingWhen power is gradually increased, reflection signal is gradually generated on two-photon resonance immediate vicinity, the reflection direction of four-wave mixing signalAnd gradually increase, work as Pc2=0.5Pc1When, atomic medium at this time is relative to the signal near two-photon resonance, just as halfSaturating semi-reflective mirror；Work as Pc2=Pc1When, the intensity of four-wave mixing reflection signal reaches maximum, illustrates that Cs atom medium is to double light at this timeThe reflectivity of the signal light at sub-resonance center reaches maximum, is equivalent to total reflective mirror.
It can be seen from Fig. 4 and Fig. 5 when signal light frequency and coupling light frequency meet two-photon resonance condition, pass throughAdjust the second half-wave plate 7 come after controlling to the watt level of coupling light, thus it is possible to vary reflectivity of the filter frequency reflecting mirror to signal light(transmissivity), and work as Pc2=Pc1When, the reflectivity of the filter frequency reflecting mirror is maximum.And the signal light of other frequency contents is not producedRaw any influence, to realize the continuously adjustable filter frequency reflection function of reflectivity.
Embodiment 2
The method of one of the present embodiment building filter frequency reflecting mirror is identical as in embodiment 1, wherein the one 45 ° is all-transMirror 15 makes signal light opposing coupler light direction pass through thermokalite metallic atom steam chest 9 with 0.14 ° of incident angles, couples the function of lightRate is 30 milliwatts, the power P of signal lights=400 microwatts.
It is identical as in embodiment 1 using the above-mentioned equipment for applying in example building filter frequency mirror approach, wherein thermokalite metalThe temperature of atom steam chest 9 is 30 degrees Celsius.
Embodiment 3
The method of one of the present embodiment building filter frequency reflecting mirror is identical as in embodiment 1, wherein the one 45 ° is all-transMirror 15 makes signal light opposing coupler light direction pass through thermokalite metallic atom steam chest 9 with 0.6 ° of incident angles, couples the function of lightRate is 5 milliwatts, the power P of signal lights=500 microwatts.
It is identical as in embodiment 1 using the above-mentioned equipment for applying in example building filter frequency mirror approach, wherein thermokalite metalThe temperature of atom steam chest 9 is 70 degrees Celsius.
Filled with Cs atom steam in thermokalite metallic atom steam chest 9 in above-described embodiment, the Cs atom can also use rubidium, sodiumEqual otheralkali metal replace.As long as the atom with multilevel system, and have and the relevant of corresponding energy level transition is excited to swashRadiant forms Λ type three-level transition structure, and filter frequency mirror function can be realized under the method for the invention.
Fig. 6 is the length of Cs atom steam chest 9 is 75mm, temperature is 30 DEG C, the forward direction that injects Cs atom steam chest 9 couples lightWith backward coupled optical power be 20 milliwatts, signal light power be 300 microwatts, coupling the detuning Δ of light frequencycUnder conditions of=0,The present invention filters the reflection efficiency of frequency reflecting mirror with the trend chart of signal angle of light.Filter frequency reflecting mirror reflection efficiency beRefer to when the reflectivity of the filter frequency reflecting mirror is equal to 1, reflected signal strength and the incoming signal light intensity of four-wave mixing signal lightRatio can be reflected by the normalization reflected signal peaks value R of four-wave mixing signal light.It will be appreciated from fig. 6 that changing entering for signal lightFiring angle, the filter frequency reflecting mirror also change correspondingly the reflection efficiency of signal light, when signal angle of light is 0.43 °, reflection effectRate is maximum.This is because the four-wave mixing process for generating the reflection signal follows the law of conservation of momentum, when signal light and coupling lightFrequency effect when atomic energy level transition, reflection efficiency under the angle is maximum.When signal light and coupling light action are in differenceAtomic energy level system or when the different atomic mediums of selection, optimal incident angle is also different.
Fig. 7 be Cs atom steam chest 9 length be 75mm, inject Cs atom steam chest 9 forward direction couple light and after to couplingOptical power is 20 milliwatts, signal light power for 300 microwatts and couples the detuning Δ of light frequencycUnder conditions of=0, the present invention filters frequencyThe reflection efficiency of reflecting mirror with Cs atom steam chest temperature change trend chart；Reflection efficiency passes through four-wave mixing signal lightReflected signal peaks value R is normalized to reflect.In figure: (1) be 0.43 ° of signal light incidence angle θ=when, filter frequency reflecting mirror reflection effectRate with the temperature change of thermokalite metallic atom steam chest variation tendency；(2) be 0.28 ° of signal light incidence angle θ=when, filter frequency reflectThe reflection efficiency of mirror with the temperature change of thermokalite metallic atom steam chest 9 variation tendency；It (3) is 0.57 ° of signal light incidence angle θ=When, filter frequency reflecting mirror reflection efficiency with thermokalite metallic atom steam chest temperature change variation tendency.As shown in Figure 7, work as letterNumber angle of light θ=0.43 °, reflection efficiency is maximum, and when incidence angle is more than or less than 0.43 °, reflection efficiency is declined；As the temperature rises, the reflection efficiency under incidence angles degree is promoted, and reaches 64 in the temperature of Cs atom steam chest 9DEG C or so when, the reflection efficiency under incidence angles degree reaches maximum value.It is 64 DEG C when the temperature of hot Cs atom steam chest 9 reaches,At 0.43 ° of signal light incidence angle θ=, reflection efficiency about 60%, when θ=0.28 °, reflection efficiency about 57%, θ=0.57 ° when,Reflection efficiency about 45% illustrates when 9 temperature of Cs atom steam chest is higher, centered on 0.43 ° of incidence angle, plus or minus about 0.2 ° of rangeIt is interior, it can obtain the reflection spectrum signal that reflection efficiency is more than 40%.
Fig. 8 is the length of Cs atom steam chest 9 is 75mm, temperature is 35 DEG C, the forward direction that injects Cs atom steam chest 9 couples lightIt is P with backward coupled optical powerc1=Pc2=20 milliwatts, signal light power be Ps=300 microwatts, signal light incidence angle θ=Reflection signal spectrogram under conditions of 0.43 °, under difference coupling light frequency is detuning.In figure: (1) being the coupling detuning Δ of light frequencycWhen=8MHz, the change curve normalization reflected signal strength R of four-wave mixing signal light detuning with signal light frequency；(2) it isCouple the detuning Δ of light frequencycWhen=41.4MHz, the normalization reflected signal strength R of four-wave mixing signal light is with signal light frequencyDetuning change curve；It (3) is the coupling detuning Δ of light frequencycWhen=82.3MHz, letter is reflected in the normalization of four-wave mixing signal lightNumber change curve intensity R detuning with signal light frequency；It (4) is the coupling detuning Δ of light frequencycWhen=123.3MHz, four-wave mixingThe change curve normalization reflected signal strength R of signal detuning with signal light frequency；It (5) is the coupling detuning Δ of light frequencyc=-When 16.7MHz, the change curve normalization reflected signal strength R of four-wave mixing signal light detuning with signal light frequency；(6) it isCouple the detuning Δ of light frequencycWhen=- 45.8MHz, the normalization reflected signal strength R of four-wave mixing signal light is with signal light frequencyDetuning change curve；It (7) is the coupling detuning Δ of light frequencycWhen=- 81MHz, letter is reflected in the normalization of four-wave mixing signal lightNumber change curve intensity R detuning with signal light frequency；It (8) is the coupling detuning Δ of light frequencycWhen=- 126.9MHz, four waves are mixedThe change curve normalization reflected signal strength R of frequency signal light detuning with signal light frequency.As shown in Figure 8, four waves of generationThe frequency location for being mixed reflected signal peaks can be with the frequency detuning Δ of coupling lightcIt is mobile, but meet two-photon resonance item alwaysPart, i.e. signal light frequency mismatching angle Δs=coupling light frequency mismatching angle Δc.Simultaneously when the coupling detuning Δ of light frequencycWhen larger, produceThe peak efficiencies of raw reflection signal can gradually decrease, but detuning within the scope of positive and negative 120MHz in coupling light frequency, still may be usedTo obtain the reflection signal that reflection efficiency reaches 40%, illustrate the reflecting mirror can obtain broad spectrum reflection efficiency it is higherFilter frequency reflection signal.Couple the detuning Δ of light frequencycIt can be adjusted, be passed through by adjusting the voltage of the first semiconductor laser 1Change the output power of first laser device 1, the i.e. general power of standing wave coupling light, to realize the company to filter frequency reflecting mirror reflection efficiencyContinuous control.
It can also change the intensity of input signal light by adjusting third half-wave plate 13 in the present invention, be reflected to adjust filter frequencyThe reflection efficiency of mirror.By changing the output power of first laser device 1, the i.e. general power of standing wave coupling light, to realize to filter frequencyThe continuous control of reflecting mirror reflection efficiency is 5-30 milliwatt in coupled optical power, and signal light power is the range of 50-500 microwattIt is interior, the present invention can be achieved.
The principle of the present invention are as follows: four-wave mixing effect is the process that wave mixing signal is generated based on atomic coberent effect, toolWhen body refers to that a pair of strong standing wave coupled field acts on atomic medium, generate atomic medium periodically to the refractive index of signal lightModulation, while improving the third-order nonlinear susceptibility of medium, when signal light frequency is with coupling light and meeting two-photon resonance,Atomic medium generates excited absorption to the signal light of the frequency content, and generates four bundles light by stimulated radiation transition form,That is four-wave mixing signal, the conservation of energy determines that the new frequency for generating light is identical as absorbed incoming signal light, and frequency is notThis part signal light for meeting two-photon resonance condition then will not be continued to propagate by excited absorption along the former direction of propagation, but can be byThe Doppler's sink effect generated to the RESONANCE ABSORPTION of Trapped ion and hot atom random motion；Meet the phase of the conservation of momentumPosition matching condition determines that four bundles light can be projected with incident light opposing coupler light direction symmetrical reverse, anti-so as to form filter frequencyPenetrate mirror effect.