四波混频研究原子里德堡态的碰撞
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摘要
四波混频是一种用途很广的光谱学技术。在四波混频光谱学中,共振增强非简并四波混频(NFWN)优于其他的四波混频光谱学,它拥有优秀的空间信号分辨率,可自由选择的相互作用体积,简单的光路,并且可以在很宽的频率范围(几百到上千的波数)内实现相位匹配。
当一个原子或分子与其它物质相碰撞时,它的固有频率会改变。碰撞效应包括谱线频移,谱线展宽,谱线不对称性和谱线伴线的产生,通过对原子分子碰撞过程的研究可以观测和分析原子分子的内部结构,还可以展开对原子核等基本粒子的研究,因此,碰撞问题有着多方面的研究价值。
本文将双光子共振非简并四波混频应用于原子高激发态的谱线频移,谱线展宽等碰撞效应的研究,得到了以下结论：
一、把双光子共振非简并四波混频用于Ba蒸汽里德堡线系的观测,实验研究了高缓冲气压条件下的里德堡线系6snd ~1D_2的碰撞展宽和频移,研究表明对于确定的里德堡态,谱线的展宽和频移与缓冲气体的压强成线性关系。
二、计算出了里德堡线系6snd ~1D_2的碰撞展宽截面和频移截面,发现碰撞展宽截面在n=17-34的范围内基本保持不变,而碰撞频移截面在n=17-34的范围内无规律起伏。
Four-wave mixing (FWM) is an important optical parametric process which has wide applications. One of the FWM spectroscopy, which may be superior to all other FWM spectroscopy, is resonance-enhanced non-degenerate four-wave mixing (NFWM). It possesses features of excellent spatial signal resolution, free choice of interaction volume and simple optical alignment. Moreover, phase matching can be achieved for a very wide frequency range from many hundreds to thousands of cm~-1.
When an atom or a molecule is surrounded by a foreign substance, its natural frequencies and the breadth of its natural frequencies are modified. The well-known pressure effects are shifts, broadening, asymmetry, and the appearance of satellites of spectral lines. Atomic and molecular interior configuration was investigated and analyzed based on atomic and molecular collision process, and elementary particle such as atomic nucleus can be investigated, too. Therefore, collision process is valuable to be investigated in many fields.
In this paper, the pressure effects of high excited states, such as pressure shift and broadening, is investigated by two-photon resonant non-degenerate four-wave mixing. The achievements made in this paper are summarized as follows:
Firstly, two-photon resonant non-degenerate four-wave mixing is used to investigate the Rydberg states in barium vapor. The pressure broadening and shift of the series 6snd ~1D_2 perturbed by argon are investigated. It is discovered that the pressure broadening and shift are linear with the pressure varying.
Secondly, the broadening cross section and shift cross section of the series 6snd ~1D_2 perturbed by argon are calculated, the broadening cross section is approximately invariable for the range from n=17 to n=34, and the shift cross section varies irregularly for the range from n=17 to n=34.
当一个原子或分子与其它物质相碰撞时,它的固有频率会改变。碰撞效应包括谱线频移,谱线展宽,谱线不对称性和谱线伴线的产生,通过对原子分子碰撞过程的研究可以观测和分析原子分子的内部结构,还可以展开对原子核等基本粒子的研究,因此,碰撞问题有着多方面的研究价值。
本文将双光子共振非简并四波混频应用于原子高激发态的谱线频移,谱线展宽等碰撞效应的研究,得到了以下结论：
一、把双光子共振非简并四波混频用于Ba蒸汽里德堡线系的观测,实验研究了高缓冲气压条件下的里德堡线系6snd ~1D_2的碰撞展宽和频移,研究表明对于确定的里德堡态,谱线的展宽和频移与缓冲气体的压强成线性关系。
二、计算出了里德堡线系6snd ~1D_2的碰撞展宽截面和频移截面,发现碰撞展宽截面在n=17-34的范围内基本保持不变,而碰撞频移截面在n=17-34的范围内无规律起伏。
Four-wave mixing (FWM) is an important optical parametric process which has wide applications. One of the FWM spectroscopy, which may be superior to all other FWM spectroscopy, is resonance-enhanced non-degenerate four-wave mixing (NFWM). It possesses features of excellent spatial signal resolution, free choice of interaction volume and simple optical alignment. Moreover, phase matching can be achieved for a very wide frequency range from many hundreds to thousands of cm~-1.
When an atom or a molecule is surrounded by a foreign substance, its natural frequencies and the breadth of its natural frequencies are modified. The well-known pressure effects are shifts, broadening, asymmetry, and the appearance of satellites of spectral lines. Atomic and molecular interior configuration was investigated and analyzed based on atomic and molecular collision process, and elementary particle such as atomic nucleus can be investigated, too. Therefore, collision process is valuable to be investigated in many fields.
In this paper, the pressure effects of high excited states, such as pressure shift and broadening, is investigated by two-photon resonant non-degenerate four-wave mixing. The achievements made in this paper are summarized as follows:
Firstly, two-photon resonant non-degenerate four-wave mixing is used to investigate the Rydberg states in barium vapor. The pressure broadening and shift of the series 6snd ~1D_2 perturbed by argon are investigated. It is discovered that the pressure broadening and shift are linear with the pressure varying.
Secondly, the broadening cross section and shift cross section of the series 6snd ~1D_2 perturbed by argon are calculated, the broadening cross section is approximately invariable for the range from n=17 to n=34, and the shift cross section varies irregularly for the range from n=17 to n=34.
引文
[1]杨向东.原子分子物理研究进展[J].西南民族学院学报：自然科学版,2001,27(2)：169-173.
[2]J. K. Crane, M. J. Shaw, R. W. Presta. Measurement of the cross sections for collisional broadening of the intercombination transitions calcium and strontium [J]. Phys. Rev. A,1994,49(3):1666-1674.
[3]阎世英.300-1200K温度下CO_2-O_2混合气体中CO_2分子谱线的压力展宽半宽度[J].青岛大学学报,2000,13(1)：91-92.
[4]E. Kuchta, R. J. AlvarezII, Y. H. Li, et al. Collisional broadening of Ba I line (553.5 nm) by He or Ar [J]. Appl. Phys. B:Photophys. Laser Chem.,1990,50(2):129-132.
[5]钱汝兰.碰撞与原子的激发[J].济宁师专学报,1999,20(6)：26.
[6]类维平,贾城.原子碰撞理论中的Oppenheimer近似[J].哈尔滨师范大学自然科学学报,2001,17(6)：28-32.
[7]阎世英,刘建华,钱青华等.600-1500K温度下H2O-Ar、H_2O-CO_2混合气体中H20分子谱线的半宽度[J].青岛大学学报,1999,12(2)：37-40.
[8]郑广,杨向东,湛昌国.400-1200K温度下C0_2-O_2混合气体中C02分子谱线的压力展宽半宽度[J].原子与分子物理学报,1998,(增刊)：77-78.
[9]郑广,杨向东,阎世英等.高温下CO_2-H_2、CO_2-CO_2混合气体中C02分子的谱线压力展宽半宽度[J].原子与分子物理学报,1999,16(1)：91-93.
[10]宋庆峰,王文中,杨向东等.H2O-N2、H_2O-H_2O混合气体中H20分子谱线的压力展宽系数[J].成都科技大学学报,1994,77：90-93.
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[12]O. G. Robert and S. Y. Ch'en. Pressure effects of foreign gases on the absorption lines of cesium. Ⅱ.The effects of helium on the first two members of the principal sesies [J]. Phys. Rev.,1966, 144(1):66-70.
[13]S. Y. Ch'en, E. Ch. Looi and O. G. Robert. Pressure effects of foreign gases on the absorption lines of cesium.Ⅲ. The effects of krypton [J]. Phys. Rev.,1967,155 (1):38-45.
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[16]D. E. Gilbert and S. Y Ch'en. Pressure effects of foreign gases on the absorption lines of cesium. Ⅵ.intensity measurements of the cesium. Resonance lines and their associated satellites in the presence of various foreign gases [J]. Phys. Rev.,1969,188(1):40-45.
[17]王福恒,王文中,杨向东.高温下H_2O-Ar、H_2O-CO_2混合气体中H2O分子谱线的半宽度[J].原子与分子物理学报,1944,11(1)：48-52.
[18]A. Jablonski. General theory of pressure broadening of spectral lines [J]. Phys. Rev.,1945,68(3-4): 78-93.
[19]T. Holstein, D. Alpert and A. O. Mccoubrey, Letters to Editor.1949,1259.
[20]U. Fano. Effects of configuration interaction on intensities and phase shifts [J]. Phys. Rev. A,1961, 124(6):1866-1878.
[21]D. K. L. Tan and S. Y. Ch'en. Pressure effects of foreign gases on the absorption lines of cesium. Ⅶ. the shift of high-member lines by various rare gases [J]. Phys. Rev. A,1970,2 (4):1124-1129.
[22]J. M. Farr and W. R. Hindmarsh. Collision broadening in the strontium resonance line, λ 4607 A [J]. J. Phys. B:At. Mol. Phys.,1971,4:568-573.
[23]R. E. M. Hedges, D. L. Drummond and A. Gallagher. Extreme-wing line broadening and Cs-inert-gas potential [J].Phys. Rev. A,1972,6(4):1519-1544.
[24]F. Biraben, B. Cagnac, E. Giacobino, et al. Broadening and shift of the sodium 3s-4D and 3s-5s two-photon lines perturbed by noble gases [J]. J. Phys. B:At. Mol. Phys.,1977,10(12):2369-2373.
[25]A. Spielfiedel, N. Feautrier, G. Chambaudt, et al. Collision broadening of the 4s4p(~3P_0)-4s5s(3S) line of calcium perturbed by hydrogen and collision induced transitions among the 4s4p(~3P_0) states [J]. J. Phys. B:At. Mol. Phys. Opt,1991,24:4711-4721.
[26]Y. C. Chan, J. A. Gelbwachs. Broadening, shifting and asymmetry of the strontium resonance line induced by rare gas perturbers [J]. J. Phys. B:At. Mol. Opt. Phys.,1992,25:3601-3602.
[27]W. DeGraffenreid, S. C. Campbell and C. J. Sansonetti. Foreign gas pressure broadening and shifts of the 2S-4S two-photon transition in lithium [J]. J. Phys. B:At. Mol. Opt.Phys.,2003,36(10): 2099-2109.
[28]B. Kerkeni, P. S. Barklem,A. Spielfiedel, et al. Collisional broadening of Mg, Sr, Ca and Na resonance lines by atomic hydrogen [J]. J. Phys. B:At. Mol. Opt. Phys.,2004,37:677-688.
[29]P. J. Oreto, Y. Y. Jau, A. B. Post, et al. Buffer-gas-induced shift and broadening of hyperfine resonances in alkali-metal vapors [J]. Phys. Rev. A,2004,69:042716.
[30]J. C. Holtgrave and P. J. Wolf. Pressure broadening and line shifting of atomic strontium 5s2'So\5s5p 3P_1 and 5s5p 3P_(0.1.2)\5s6s 3S_1 absorption transitions induced by noble-gas collisions [J]. Phys. Rev. A, 2005,72:012711.
[31]G. Ferrari, P. Cancio, R. Drullinger, et al. Precision frequency measurement of visible intercombination lines of strontium [J]. Phys. Rev. Lett.,2003,91(24):243002.
[32]Y. R. Shen. The Principles of Nonliner Optics. John Willey & Sons, Inc. New York,1984.
[33]程文芹.原子自电离态的研究[J].物理,1985,14(9)：523-529.
[34]M. Aymar, O. Robaux. Multichannel quantum-defect analysis of the bound even-parity J=2 spectrum of neutral barium [J]. J. Phys. B,1979,12(4):531-546.
[35]J. Lü, Ch. J. Dai, Y. F. Xu, et al. Perturbed 6snd ~(1.3)D_2 Rydberg series of neutral barium [J]. Chin. Phys. Lett.,2001,18(9):1192-1195.
[36]N. M. Shen and S. M. Curry.Multiphoton excitation of potassium [J]. Opt. Commun.,1977,20(3): 392-396.
[37]林美荣,张包铮.原子光谱学导论.科学出版社,1990，290.
[38]谢卫军,方达渭.用延迟脉冲场电离方法测量Na原子里德堡态的寿命[J].九江师专学报：自然科学版,1995,14(5)：12-15.
[39]沈元壤著,顾世杰译.非线性光学原理.科学出版社,1987,261.
[40]刘颂豪,赫光生.强光光学及其应用.广东科技出版社,1995，145.
[41]S. C. Abbi and S. A. Ahmad. Non-linear optics and laser spectroscopy. Narosa publishing house,2001, 205.
[42]钱士雄,王恭明.非线性光学-原理与进展.复旦大学出版社,1996，137.
[43]石顺祥,陈国夫,赵卫等.非线性光学.西安电子科技大学出版社,2003,268.
[44]李淳飞.非线性光学.哈尔滨工业大学出版社,2005，60.
[45]叶佩弦.非线性光学.中国科学技术出版社,1998,52.
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[54]B. Kaulakys. Broadening and shift of Rydberg levels by elastic collisions with rare-gas atoms[J]. J. Phys. B:At. Mol. Phys.1984,17:4485-4497.
[2]J. K. Crane, M. J. Shaw, R. W. Presta. Measurement of the cross sections for collisional broadening of the intercombination transitions calcium and strontium [J]. Phys. Rev. A,1994,49(3):1666-1674.
[3]阎世英.300-1200K温度下CO_2-O_2混合气体中CO_2分子谱线的压力展宽半宽度[J].青岛大学学报,2000,13(1)：91-92.
[4]E. Kuchta, R. J. AlvarezII, Y. H. Li, et al. Collisional broadening of Ba I line (553.5 nm) by He or Ar [J]. Appl. Phys. B:Photophys. Laser Chem.,1990,50(2):129-132.
[5]钱汝兰.碰撞与原子的激发[J].济宁师专学报,1999,20(6)：26.
[6]类维平,贾城.原子碰撞理论中的Oppenheimer近似[J].哈尔滨师范大学自然科学学报,2001,17(6)：28-32.
[7]阎世英,刘建华,钱青华等.600-1500K温度下H2O-Ar、H_2O-CO_2混合气体中H20分子谱线的半宽度[J].青岛大学学报,1999,12(2)：37-40.
[8]郑广,杨向东,湛昌国.400-1200K温度下C0_2-O_2混合气体中C02分子谱线的压力展宽半宽度[J].原子与分子物理学报,1998,(增刊)：77-78.
[9]郑广,杨向东,阎世英等.高温下CO_2-H_2、CO_2-CO_2混合气体中C02分子的谱线压力展宽半宽度[J].原子与分子物理学报,1999,16(1)：91-93.
[10]宋庆峰,王文中,杨向东等.H2O-N2、H_2O-H_2O混合气体中H20分子谱线的压力展宽系数[J].成都科技大学学报,1994,77：90-93.
[11]S. Y. Ch'en and O. G. Robert. Pressure effects of foreign gases on the absorption lines of cesium. Ⅰ.The effects of argon on the first two members of the principal sesies [J]. Phys. Rev.,1966,144(1): 59-65.
[12]O. G. Robert and S. Y. Ch'en. Pressure effects of foreign gases on the absorption lines of cesium. Ⅱ.The effects of helium on the first two members of the principal sesies [J]. Phys. Rev.,1966, 144(1):66-70.
[13]S. Y. Ch'en, E. Ch. Looi and O. G. Robert. Pressure effects of foreign gases on the absorption lines of cesium.Ⅲ. The effects of krypton [J]. Phys. Rev.,1967,155 (1):38-45.
[14]O. G. Robert, S. Y. Ch'en and E. Ch. Looi. Pressure effects of foreign gases on the absorption lines of cesium.Ⅳ. The effects of neon [J]. Phys. Rev.,1967,156(1):48-54.
[15]S. Y. Ch'en, D. E. Gilbert and D. K. L. Tan. Pressure effects of foreign gases on the absorption lines of cesium. Ⅴ.The effects of xenon and CF4 [J]. Phys. Rev.,1969,184(1):51-55.
[16]D. E. Gilbert and S. Y Ch'en. Pressure effects of foreign gases on the absorption lines of cesium. Ⅵ.intensity measurements of the cesium. Resonance lines and their associated satellites in the presence of various foreign gases [J]. Phys. Rev.,1969,188(1):40-45.
[17]王福恒,王文中,杨向东.高温下H_2O-Ar、H_2O-CO_2混合气体中H2O分子谱线的半宽度[J].原子与分子物理学报,1944,11(1)：48-52.
[18]A. Jablonski. General theory of pressure broadening of spectral lines [J]. Phys. Rev.,1945,68(3-4): 78-93.
[19]T. Holstein, D. Alpert and A. O. Mccoubrey, Letters to Editor.1949,1259.
[20]U. Fano. Effects of configuration interaction on intensities and phase shifts [J]. Phys. Rev. A,1961, 124(6):1866-1878.
[21]D. K. L. Tan and S. Y. Ch'en. Pressure effects of foreign gases on the absorption lines of cesium. Ⅶ. the shift of high-member lines by various rare gases [J]. Phys. Rev. A,1970,2 (4):1124-1129.
[22]J. M. Farr and W. R. Hindmarsh. Collision broadening in the strontium resonance line, λ 4607 A [J]. J. Phys. B:At. Mol. Phys.,1971,4:568-573.
[23]R. E. M. Hedges, D. L. Drummond and A. Gallagher. Extreme-wing line broadening and Cs-inert-gas potential [J].Phys. Rev. A,1972,6(4):1519-1544.
[24]F. Biraben, B. Cagnac, E. Giacobino, et al. Broadening and shift of the sodium 3s-4D and 3s-5s two-photon lines perturbed by noble gases [J]. J. Phys. B:At. Mol. Phys.,1977,10(12):2369-2373.
[25]A. Spielfiedel, N. Feautrier, G. Chambaudt, et al. Collision broadening of the 4s4p(~3P_0)-4s5s(3S) line of calcium perturbed by hydrogen and collision induced transitions among the 4s4p(~3P_0) states [J]. J. Phys. B:At. Mol. Phys. Opt,1991,24:4711-4721.
[26]Y. C. Chan, J. A. Gelbwachs. Broadening, shifting and asymmetry of the strontium resonance line induced by rare gas perturbers [J]. J. Phys. B:At. Mol. Opt. Phys.,1992,25:3601-3602.
[27]W. DeGraffenreid, S. C. Campbell and C. J. Sansonetti. Foreign gas pressure broadening and shifts of the 2S-4S two-photon transition in lithium [J]. J. Phys. B:At. Mol. Opt.Phys.,2003,36(10): 2099-2109.
[28]B. Kerkeni, P. S. Barklem,A. Spielfiedel, et al. Collisional broadening of Mg, Sr, Ca and Na resonance lines by atomic hydrogen [J]. J. Phys. B:At. Mol. Opt. Phys.,2004,37:677-688.
[29]P. J. Oreto, Y. Y. Jau, A. B. Post, et al. Buffer-gas-induced shift and broadening of hyperfine resonances in alkali-metal vapors [J]. Phys. Rev. A,2004,69:042716.
[30]J. C. Holtgrave and P. J. Wolf. Pressure broadening and line shifting of atomic strontium 5s2'So\5s5p 3P_1 and 5s5p 3P_(0.1.2)\5s6s 3S_1 absorption transitions induced by noble-gas collisions [J]. Phys. Rev. A, 2005,72:012711.
[31]G. Ferrari, P. Cancio, R. Drullinger, et al. Precision frequency measurement of visible intercombination lines of strontium [J]. Phys. Rev. Lett.,2003,91(24):243002.
[32]Y. R. Shen. The Principles of Nonliner Optics. John Willey & Sons, Inc. New York,1984.
[33]程文芹.原子自电离态的研究[J].物理,1985,14(9)：523-529.
[34]M. Aymar, O. Robaux. Multichannel quantum-defect analysis of the bound even-parity J=2 spectrum of neutral barium [J]. J. Phys. B,1979,12(4):531-546.
[35]J. Lü, Ch. J. Dai, Y. F. Xu, et al. Perturbed 6snd ~(1.3)D_2 Rydberg series of neutral barium [J]. Chin. Phys. Lett.,2001,18(9):1192-1195.
[36]N. M. Shen and S. M. Curry.Multiphoton excitation of potassium [J]. Opt. Commun.,1977,20(3): 392-396.
[37]林美荣,张包铮.原子光谱学导论.科学出版社,1990，290.
[38]谢卫军,方达渭.用延迟脉冲场电离方法测量Na原子里德堡态的寿命[J].九江师专学报：自然科学版,1995,14(5)：12-15.
[39]沈元壤著,顾世杰译.非线性光学原理.科学出版社,1987,261.
[40]刘颂豪,赫光生.强光光学及其应用.广东科技出版社,1995，145.
[41]S. C. Abbi and S. A. Ahmad. Non-linear optics and laser spectroscopy. Narosa publishing house,2001, 205.
[42]钱士雄,王恭明.非线性光学-原理与进展.复旦大学出版社,1996，137.
[43]石顺祥,陈国夫,赵卫等.非线性光学.西安电子科技大学出版社,2003,268.
[44]李淳飞.非线性光学.哈尔滨工业大学出版社,2005，60.
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