英文版利用牛顿环方法测量激光波长.doc

Liaoning Normal University开放实验室项目研究论文 题 目： 利用牛顿环方法测量激光波长学 院： 物理与电子技术学院专 业： 物理学（师范）班级序号： 2班05号学 号： 20081125020018 学生姓名： 牛萌 指导教师： 张敏 2011年 月Measurement of the wavelength of He-Ne Laser by means of Newtons ringMeng Niu, Min ZhangSchool of Physics and Electronic Technology, Major: Physics, Grade: 08 Abstract: The traditional method of measuring wavelength used some more high accuracy and complex operation of instruments, which caused many inconveniences to the actual application. This paper gives a new method to measure the wavelength of laster by a new means of Newtons ring and the results of the diffraction grating measuring laser wavelength also have a high accuracy.Key words: He-Ne Laser; Laser wavelength; Newtons ring.Introduction Laser as a light source because its monochromatic good, orientation of strong, dispersion characteristics such as less in modern science and technology and engineering practice in a wide range of applications. In the actual measurement generally used to know in advance the wavelength of laser source. Different materials and luminous mechanism of laser source has different wavelength. Therefore, how to determine the wavelength of the laser is has the very vital significance. Newtons ring is a kind of method of amplitude points such as interference phenomenon of thick, the earliest for Newton found. In order to study the color of the film, Newton had been carefully studied convex surface of glass peace experiment device. His most valuable achievements is found by measuring the concentric circles of radius it out of a burning glass and plane between the thickness of the air layer corresponding position; Corresponding to the air layer thickness and bright ring 1, 3, 5. In proportion, corresponding to the air layer thickness and dark rings 0, 2, 4. In proportion. But because he advocated light particles said (light interference is the volatility of the light of a kind of expression) and failed to make the correct explanation for it. Until the early nineteenth century, Thomas YangCai run out of interference principle explains Newton ring phenomenon, and the measured results of reference Newton calculated the different colors of light wavelengths and frequency.1 Experiment1.1 Experiment principle Newtons ring device from a piece of radius of curvature superior even convex glass lens, put its convex component on a piece of optical glass panel (is even crystal) of, such as figure 1 show. The of the convex and the glass panel of even convex lens forms the 1 F air thin film, its thickness raises gradually from make contact in the centre to rim. If project light upon Newton by parallel homogeneous light vertical in the ring, then through air layer up, descend surface reflection of two beam of light existence the optical path is bad, they after the convex of even convex lens meets, interfere with occurrence. It interferes with drawing is take glass make contact as central series the united at heart circle of the dark phase to phase clearly ring(such as figure 2 show), be termed Newtons ring. Because same interference ring ascends everywhere of the air layer thickness is same, therefore be termed to wait a thick interference.Fig.1 Newtons ring equips Fig.2 Interference circle ringWhen the wavelength of the x for sodium yellow light on flat vertical to the burning, the liquid membrane, under the surface of the light reflected light path difference and interference countervail. The dark conditions： （1）Type E is a dark stripe center, where the liquid film thickness, K interference.Using the geometry of the figure, available： ( r stripe radius ),substitution (1 )type, is: （2）The dark grain radius: （3）If taking dark lines observed, then the m, K level corresponding to the dark ring radius squared （4） （5） The two type of very flat convex lens radius of curvature （6）Observation of Newtonian ring when we will find the ring center due to the deformation, dust, water and so on, center is not a point, but an indistinct dark or light spot. Head thus center is not easy to identify. It is often taken to replace the dark ring diameter. （7）Similarly for the air film, is: （8） Type ( 7) and type ( 8), available: （9）1.2 Experimental apparatusA reading microscope, Sodium light source, Newtons ring apparatus, He-Ne laser, Beam expanding lens, A polarizer, Plano-convex lens. Fig.3 Reading microscope Fig.4 Sodium light source Fig.5 Newton ring instrument 1.3 Make use of Newtons ring to measure even convex lens radius of curvature.（1）Set Newtons ring in the reading microscope workbench frosted glass the center, and make microscope body tube just vs Newton ring device centre, spark a sodium optics lamp, make it just vs the reflecting mirror of reading microscope thing scope.（2）Regulate reading microscope. Firstly, regulate eyepiece: Making the row the cross of board to engrave wire is clear it is thus clear that, and slewing eyepiece, make the cross engrave wire of horizontal the direction engraving wire and showing minute details the movement of body tube is parallel. Secondly, regulate reflecting mirror: Is a microscope to see brightness maximum in field, at this time fundamental satisfy go into cast light vertical is at the request that need to be measured lens. Thirdly, slewing hand wheel: make to show minute details body tube translation to the surveyors rod mid, and regulate to adjust burnt hand wheel , make the thing scope approach Newton ring device table. Lastly, adjusting vs the reading microscope is burnt: Slowly the slewing adjusts burnt hand wheel , make to show minute details body tube from bottom to top the movement progress adjust burnt, until clearly see Newton ring an interference streaking from the eyepiece see the field and take no cognizance bad; Then move Newton again ring device, make the cross in the eyepiece engrave wire to hand over dot and ring centre in Newton mostly polymerrization.(3) Measure the diameter of dark ring. The slewing reading microscope count drum observes in the eyepiece at the same time and make the cross engrave wire from Newtons ring the central slowness move into 56 rings to a side then send back number 55 rings, from number 55 ring begin one side to movement the cross engrave wire and move a ring to stick down homologous count each 5 rings until number 35rings, Then again from together side number 30 rings start recording number10 ring; Wear dark spot in the super - centre, from another one side number 10 ring begin one by one in order record count arrive number 30 rings, then from number 35 rings until number 55 rings. Combine the data charge to data table measured amid.(4) Use of Newtonian ring laser wavelength measurement ( has been used to measure the radius of curvature of the plano-convex lens )The adjustment experiment device: take He-Ne laser, a plano-convex lens, microscope, polarizing plate two, as shown in the optical path for light, laser, laser, careful regulation of plano-convex lens and a reading microscope, in reading microscope observed in Newton ring, adjusting the polarizing plate 2, 3 of the polarization angle, the Newtonian rings the brightness moderate, then, to detect the M Newton ring diameter of Dm and the N ring diameter Dn, into the formula: calculate the wavelength of laser 1.He-Ne Laser machine 2.polarizer 3.polarizer 4.plano-convex lens 5.reading microscopeFig.6 The experiment equips sketch map2 Data record2.1 Data recordingTable1：Sodium lamp of Newtonian ring dataThe number of rings(mm)The number of rings(mm)2m(mm)(mm)n(mm)(mm)5530.68319.55811.1253029.34520.8868.45952.21152.4970.340890.85.85030.44419.79410.6502529.02421.2167.80852.4584530.18720.04510.1422028.66321.5587.10552.3794029.94520.3089.6371528.27321.9496.34252.6503529.64320.5999.0441027.81522.4215.39452.699Data table to take the M-N = 25, error: 0.005mm 9 at room temperatureHe-Ne laser Newton rings dataTable 2: He-Ne laser Newton rings dataData table to take the M-N = 25, error: 0.005mm 9 at room temperatureThe number of rings(mm)The number of rings(mm)2m(mm)(mm)n(mm)(mm)5530.15020.2399.9113028.82821.4087.42040.18243.3840.202890.85.85029.94820.4479.5012528.54321.6946.84940.3644529.73320.6709.0632028.23422.0036.23240.3014029.52120.8918.6301527.89922.3365.56340.5233529.27221.1528.1201027.48322.7524.73140.5502.2 Data processing(1) In sodium light to determine the radius of curvature of the convex lens convex optimal valueD55=XL55-XR55=30.683mm-19.558mm=11.125mmD50=XL50-XR50=30.444mm-19.794mm=10.650mmD45=XL45-XR45=30.187mm-20.045mm=10.142mmD40=XL40-XR40=29.945mm-20.308mm= 9.637mmD35=XL35-XR35=29.643mm-20.599mm= 9.044mmD30=XL30-XR30=29.345mm-20.886mm= 8.459mmD25=XL25-XR25=29.024mm-21.216mm= 7.808mmD20=XL20-XR20=28.663mm-21.588mm= 7.105mmD15=XL15-XR15=28.273mm-21.949mm= 6.342mmD10=XL10-XR10=27.815mm-22.421mm= 5.394mmMake Dm2-Dn2=MD552-D302=(11.125mm)2-(8.459mm)2=52.211mm2D502-D252=(10.650mm)2-(7.808mm)2=52.458mm2D452-D202=(10.142mm)2-(7.105mm)2=52.397mm2D402-D152=( 9.637mm)2-( 6.342mm)2=52.650mm2D352-D102=( 9.044mm)2-( 5.394mm)2=52.699mm2The radius of curvature of the best value(2）The known convex curvature radius convex calculation laser wavelength D55=XL55-XR55=30.150mm-20.239mm= 9.911mmD50=XL50-XR50=29.948mm-20.447mm= 9.501mmD45=XL45-XR45=29.733mm-20.670mm= 9.063mmD40=XL40-XR40=29.521mm-20.891mm= 8.630mmD35=XL35-XR35=29.272mm-21.152mm= 8.120mmD30=XL30-XR30=28.828mm-21.408mm= 7.420mmD25=XL25-XR25=28.543mm-21.694mm= 6.849mmD20=XL20-XR20=28.234mm-22.002mm= 6.232mmD15=XL15-XR15=27.899mm-22.336mm= 5.563mmD10=XL10-XR10=27.483mm-22.752mm= 4.731mmMake Dm2-Dn2=MD552-D302=(9.911mm)2-(7.420mm)2=43.182mm2D502-D252=(9.501mm)2-(6.849mm)2=43.364mm2D452-D202=(9.063mm)2-(6.232mm)2=43.301mm2D402-D152=(8.630mm)2-(5.563mm)2=43.523mm2D352-D102=(8.120mm)2-(4