1. Modeling the coupling between cw lasers and a frequency comb in atomic samples
Marco Polo, Daniel Felinto and Sandra Vianna
Departamento de Física
Universidade Federal de Pernambuco

2. Index 1 - Introduction 2 - Coherent accumulation and frequency comb
3 - Theoretical model
4 - Results
5 - Conclusions

3. Introduction Rb vapor Ti:sapphire
We use a cw laser to probe the interaction of a frequency comb in an atomic vapor in regime of intense field.
Rb vapor
Ti:sapphire
We are interested in the situation where the repetition rate of fs laser is greater than the atomic relaxation rate, coherent accumulation processes.

4. Coherent accumulation and frequency comb

5. Coherent accumulation and frequency comb
Two-level sistem:
on resonance
atoms stopped * *
groups of atoms with different velocities *
D. Felinto et al, Opt. Comm. (2003)

6. Theoretical model
Model based on the energy levels of Rb, in the transition
Rb and fs laser parameters:

7. Theoretical model
Model based on the energy levels of Rb, in the transition
Equation of Liouville:
Transmission of laser cw:
Approaches:
1 – slow envelope
Rb and fs laser parameters:
2 – rotating wave approximation

8. Bloch equations
time of flight atoms

9. fs intensity dependence
Change in the transmission of cw field induced by the presence of the fs field:

10. fs intensity dependence
Change in the transmission of cw field induced by the presence of the fs field:

11. fs pulses of the order of pi
Two-level sistem:
Bloch sphere

12. fs pulses of the order of pi
Three-level sistem:
For a single pulse:
periodic behavior with

13. Open and closed transitions

14. Open and closed transitions
Theory
Experiment

15. Summary
We presented theoretical results of the coupling between a cw laser and a frequency comb in atomic vapor where TR < Tij.
Effects of coherence and population accumulation are observed in the transmission variation of the cw laser induced by the fs laser.
Dependence with:
Different atom group velocities
fs intensity
Open and closed transition – optical pumping process
We observe good agreement between theoretical and experimental data.
We intend to use the cw laser to study electromagnetic induced transparency by the fs laser.

16. Thank you!