Transit Time Broadening and Laser-Dressed State Interference Effects in Spectral Profiles of Atoms Interacting with Coherent Light

Size: px

Start display at page:

Download "Transit Time Broadening and Laser-Dressed State Interference Effects in Spectral Profiles of Atoms Interacting with Coherent Light"

Griffin Holland
5 years ago
Views:

1 .... Transit Time Broadening and Laser-Dressed State Interference Effects in Spectral Profiles of Atoms Interacting with Coherent Light Juris Ulmanis N. N. Bezuglov, K. Miculis, B. Mahrov, A. Ekers University of Latvia Laser Centre IONS 7, Galway 1 / 13

2 Contents...1 Transit time broadening Broadening of spectral line Experiment and results...2 Laser-dressed state interference Introduction and Autler-Townes effect Double slit experiment in an atom 2 / 13

3 Transit time broadening Broadening of spectral line Transit time effect broadens line shape Laser Large interaction time Velocity-selective optical pumping Transit relaxation I(x) Finite interaction time t t sp E t 2 2w x 3 / 13

4 Transit time broadening Broadening of spectral line Transit time effect broadens line shape Laser Large interaction time Velocity-selective optical pumping Transit relaxation I(x) Finite interaction time t t sp E t 2 2w x 3 / 13

5 Transit time broadening Broadening of spectral line Transit time effect broadens line shape Laser Large interaction time Velocity-selective optical pumping Transit relaxation I(x) Finite interaction time t t sp E t 2 2w x 3 / 13

6 Transit time broadening Broadening of spectral line Important correction for small transit times Classical line width ( ω = τ sp τsp 2 Corrected ω res = 1 + 4,8ln(2) 4τsp 2 τtran 2 ) + 8Ln(2) τtran 2 Ω res Ω Relation between line widths arising from classical and density matrix approach as a function of the transit time. Calculation for the spontaneous life time of the excited level τ = 17 ns.. 4 / 13

7 Transit time broadening Broadening of spectral line Curved wavefronts introduce additional broadening Broadened line width: ω vf = ω 1 + ϕ 2 5 / 13

8 Transit time broadening Experiment and results Processes in supersonic Na 2 beam x detector Supersonic beam: cm 3 concentration Population distribution peaks at X 1 Σ + g (v=0, J=7) Collimation angle 0, 7 o Lasers: cw; CR-699 ν las = 1MHz, ν Dop = 1MHz 6 / 13

9 Transit time broadening Experiment and results Processes in supersonic Na 2 beam x detector Supersonic beam: cm 3 concentration Population distribution peaks at X 1 Σ + g (v=0, J=7) Collimation angle 0, 7 o Lasers: cw; CR-699 ν las = 1MHz, ν Dop = 1MHz 6 / 13

10 Transit time broadening Experiment and results Processes in supersonic Na 2 beam x detector Supersonic beam: cm 3 concentration Population distribution peaks at X 1 Σ + g (v=0, J=7) Collimation angle 0, 7 o Lasers: cw; CR-699 ν las = 1MHz, ν Dop = 1MHz 6 / 13

11 Transit time broadening Experiment and results 30% increase over the line width predicted by classical theory detector Fluorescence intensity (a.u.) 1,0 0,8 0,6 0,4 0,2 P =1500 MHz 0, (MHz) S 7 / 13

12 Introduction and Autler-Townes effect Dressed (adiabatic) states Bare states H total = H atom Dressed (adiabatic) states H total = H atom + H light-atom Φ 1 = cosθ(t) f sinθ(t) e Φ 2 = sinθ(t) f + cosθ(t) e tan(2θ) = Ω S(t) S = µgee(t) S 8 / 13

atom + H light-atom H total = H atom Φ 1 = cosθ(t) f sinθ(t)

13 Introduction and Autler-Townes effect Dressed (adiabatic) states Bare states Dressed (adiabatic) states H total = H atom + H light-atom H total = H atom Φ 1 = cosθ(t) f sinθ(t) e Φ 2 = sinθ(t) f + cosθ(t) e tan(2θ) = Ω S(t) S = µ gee(t) S 8 / 13

14 Introduction and Autler-Townes effect Autler-Townes doublet Φ 1 = cosθ(t) f sinθ(t) e Φ 2 = sinθ(t) f + cosθ(t) e tan(2θ) = Ω S(t) S Ω S (t) = µ gee(t) 0 θ π/2 9 / 13

15 Introduction and Autler-Townes effect Autler-Townes doublet Φ 1 = cosθ(t) f sinθ(t) e Φ 2 = sinθ(t) f + cosθ(t) e tan(2θ) = Ω S(t) S Ω S (t) = µ gee(t) 0 θ π/2 9 / 13

16 Introduction and Autler-Townes effect Autler-Townes doublet Φ 1 = cosθ(t) f sinθ(t) e Φ 2 = sinθ(t) f + cosθ(t) e tan(2θ) = Ω S(t) S Ω S (t) = µ gee(t) 0 θ π/2 9 / 13

17 Double slit experiment in an atom The wrong experiment 10 / 13

18 Double slit experiment in an atom The wrong experiment 10 / 13

19 Double slit experiment in an atom The wrong experiment e' g' f ' time 10 / 13

20 Double slit experiment in an atom Population control of long lived atomic states e' g' f ' c b a time a b c time, μs 11 / 13

21 Double slit experiment in an atom First experimental results in Na atoms f 8S 1 2 F=2 F=1 25 MHz S e 3P 1 2 F=2 F=1 188 MHz P F=2 g 3S GHz F=1 12 / 13

22 Double slit experiment in an atom First experimental results in Na atoms f e g 8S 1 2 3P 1 2 3S 1 2 S P F=2 F=1 F=2 188 MHz F=1 F=2 25 MHz 1.72 GHz Fluorescence from level f, (a.u.) 1,0 0,8 0,6 0,4 0, S laser detuning, MHz F=1 12 / 13

23 Double slit experiment in an atom molecular beam laboratory 13 / 13

Absorption and Fluorescence Studies on Hyperfine Spectra of Rb and Dressed state picture

Absorption and Fluorescence Studies on Hyperfine Spectra of Rb and Dressed state picture Sabyasachi Barik National Institute of Science Education and Research, Bhubaneswar Project guide- Prof. C.S.Unnikrishnan