48. Doppler-Free Laser Saturation Spectroscopy

Traditionally, optical spectroscopy had been performed by dispersing the light emitted by excited matter, or by dispersing the light transmitted by an absorber. Alternatively, if one has available a tunable monochromatic source (such as certain lasers), a spectrum can be measured 'one wavelength at a time' by measuring light intensity (fluorescence or transmission) as a function of the wavelength of the tunable source.

In either case, physically important structures in such spectra are often obscured by the Doppler broadening of spectral lines that comes from the thermal motion of atoms in the matter. In this experiment you will make use of an elegant technique known as Doppler-free saturated absorption spectroscopy that circumvents the problem of Doppler broadening. The primary experimental objective will be to use this technique to measure the hyperfine splittings in the S_1/2 and P_1/2 states of Rb. In addition, you will learn a bit about lasers in general and diode lasers in particular.

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References (certificates required)

1. [1973] M. S. Feld and V. S. Letokhov, "Laser Spectroscopy", Sci. Am., 229, 69-85 (Dec., 1973), Dewey Library Basement
2. [1976] V. S. Letokhov, Saturation Spectroscopy;, Topics in Applied Physics, Chapter 4, Edited by K. Shimoda, Springer-Verlag (1976)
3. [1977] V. S. Letokhov and V. P. Chebotayev, Nonlinear Laser Spectroscopy, pp. 1-35, (Springer Series in Optical Sciences , Vol. 4), Springer-Verlag (New York, 1977)
4. [1980] G.K. Woodgate,Chapter 9: Hyperfine structure and isotope shift pp. 168-187 in Elementary Atomic Structure, Oxford University Press, (1980)
5. [1980] P. G. Pappas et al., "Saturation Spectroscopy with Laser Optical Pumping in Atomic Barium," Phys. Rev. 21A, 1955-68 (1980)
6. [1982] C. Aminoff and M. Pinard, Velocity selective optical pumping; J. Physique 43, pp. 263-277 (1982)
7. [1984a] S. Nakayama,,Theoretical Analysis of Rb and Cs D2 Lines in Saturation Spectroscopy with Optical Pumping: Part I, Journal of the Physical Society of Japan, Vol. 23, No. 7, July 1984, pp. 879-883
8. [1984b] S. Nakayama,Velocity Selective Optical Pumping Spectroscopy of D1 Lines in Alkali Atoms, Journal of the Physical Society of Japan, Vol. 53, No. 10, October 1984, pp. 3351-3361
9. [1984c] S. Nakayama,Theoretical Analysis of Rb and Cs D2 Lines in Doppler-Free Spectroscopic Techniques with Optical Pumping - Part II, Journal of the Physical Society of Japan, Vol. 24, XNo. 1, January 1985, pp. 1-7
10. [1985] J. C. Camparo, "The Diode Laser in Atomic Physics," Contemp. Phys. 27, 443-477 (1985)
11. [1989] J.R. Brandenberger,"Hyperfine splittings in 4p5 5p configuration of (83)Kr using saturated absorption laser spectroscopy", Physical Review A, Vol. 39, No. 1, January, (1989)
12. [1991] C. E. Wieman and L. Hollberg, "Using Diode Lasers for Atomic Physics", Rev. Sci. Instrum., 62 (1), 1-20 (1991)
13. [1991], J. Brandenberger,Notes on Diode Lasers (1991)
14. [1992] K. B. MacAdam, A. Steinbach, and C. Wieman, "A narrow-band tunable diode laser system with grating feedback and a saturated absorption spectrometer for Cs and Rb" Am. J. Phys. 60 (12), 1098-1111 (1992)
15. [2001] D. Steck "Rb-87 Properties"Los Alamos Theoretical Division (T-8) September 2001
16. [2001] Sample Data (2001)
17. [2002] Results from Prof. Chuang (2002)

Selected Resources

1. Fabry-Perot Mirrors (CVI Part Number PR1-780.0-90-1037-C)
2. Tui-Optics Laser System Brochure
   1. Part I, II, III: Introduction, Safety Instructions and Quickstart/Troubleshooting
   2. Part IV Diode Laser Head DL 100
   3. Part V Supply Rack DC 100 with Monitor Unit
   4. Part VII Temperature Control DTC 100
   5. Part IX Lock-In Regulator LIR 100
   6. Part VIII Scan Control SC 100
   7. Part XI Pound Drever-Detector PDD 100
   8. Part XII Computer Analog Interface DCB 100
   9. Part XIII Warranty and Service
3. Burleigh WA-2000S Wavemeter Jr.
4. Panasonic CCD Camera WV-BL200
5. MIT Balanced Detector -- Bernie Wadsworth Oct 2002
6. Glendale Laser Eye Protection (755-855nm OD>4) 3943

Selected Resources