A model system for adaptive strong field control

Transcription

1 A model system for adaptive strong field control M. Wollenhaupt, T. Bayer and T. Baumert Universität Kassel Institut für Physik

2 Principle of adaptive control 2

3 Shaping light: full control over the light field envelope, frequency and polarization Springer Handbook of Laser and Optics, Chap. 12 Femtosecond Laser Pulses: Linear Properties, Manipulation, Generation and Measurement, (2007) 3

4 Shaping light: experimental layout Rev. Sci. Inst., 74, 4950, (2003) 4

5 Experimental demonstration of adaptive control AB + C ABC A + BC 5

6 Experimental results 6

7 Some examples of adaptive control Automated pulse compression (Gerber/Baumert; Silberberg 1997) Population transfer in dyes (Bardeen/Wilson 1997) Photo-dissociation of complex molecules (Gerber/Baumert 1998; Levis/Rabitz 2001; Wöste 2003.) Shaping of Rydberg wave packets (Weinacht/Bucksbaum 1999) Energy flow in light harvesting systems (Herek/Motzkus 2002) Selectivity in liquid phase and isomerization (Brixner/Gerber 2001 and 2005; Miller 2006) Polarization control of MPI (Wollenhaupt/Brixner/Gerber/Baumert 2004) Molecular alignment (Wollenhaupt/Baumert/Banares 2006) Selective population of dressed states (Wollenhaupt/Baumert 2005) Semiconductor nonlinearities (Keller 2000) High harmonic generation (Murnane/Kapteyn; Gerber/Pfeiffer/Spielmann) Polarization-shaping applied to nano structures (Aeschlimann/Brixner/Pfeiffer 2007) J. Phys. B, 41, Special Issue on Quantum Control (2008) 7

8 A model system for strong field control: MPI of potassium atoms Autler Townes doublet Slow Fast Fitness J. Phys. B., 41, , (2008) 8

9 Why Well established simple model system Insights into physical mechanisms Relevant to strong field control: non-perturbative interaction Complex dynamics due to complex pulses Experimentally accessible: open- and closed-loop results Physical interpretation of optimization results via dressed states Can be generalized to control of molecular dynamics 9

10 Strong-field control: the general picture 10

11 Strong-field control: the general picture Target state control is achieved by control of ➊ dressed state populations ➋ dressed state energies Selectivity Tunability 11

12 Experimental implementation Opt. Commun., 264, 285, (2006) Phys. Rev. Lett, 89, , (2002) 12

13 Open-loop results for specific pulse shapes Phys. Rev. A, 68, , (2003) Phys. Rev. A, 73, , (2006) J. Mod. Opt., 52, 2187, (2005) Chem. Phys. Lett., 419, 184, (2006) Appl. Phys. B, 82, 183, (2006) 13

14 Experimental closed-loop results J. Opt. B, 7, S 270, (2005) 14

15 Shaped light & matter: the math 15

16 Shaping light Springer Handbook of Laser and Optics, Chap

17 Shaping light Springer Handbook of Laser and Optics, Chap

18 Shaping light Springer Handbook of Laser and Optics, Chap

19 Shaping light Springer Handbook of Laser and Optics, Chap

20 Interaction of light and matter: a simple model system TDSE Two state system Hamiltonian Annu. Rev. Phys. Chem, 56, 25, (2005) 20

21 The numerical problem I Differential equation Initial condition Annu. Rev. Phys. Chem, 56, 25, (2005) 21

22 The numerical problem II Photoelectron spectrum Slow Fast Fitness 22

23 J. Phys. B., 41, , (2008), Special Issue on Quantum Control: Download supplementary movies 23

24 The physical picture of photon locking Physical mechanism: Selective Population Of Dressed States (SPODS) J. Phys. B., 41, , (2008), Special Issue on Quantum Control: Download supplementary movies 24

25 Pulse parameterization based on physical insights Rapid Adiabatic Passage Chirp: continuous phase variation Photon Locking Pulse sequences: phase jumps Combining quadratic- and sinusoidal phase functions: delivers sequence of chirped pulses with phase jumps 25

26 The structure of search space: landscapes -surface J. Phys. B., 41, , (2008) 26

27 Control landscapes: extract physical insights -surface PL 0 RAP Multi RAP Multi RAP

28 Experimental 2d quantum control landscapes J. Phys. B., 41, , (2008) 28

29 Towards landscapes in high dimensions -surfaces -surfaces 29

30 Iso-surfaces on 3d landscapes: level sets Lower dressed state Upper dressed state 30

31 Sections: 2d landscapes -surfaces 31

32 Sections: 2d landscapes -surfaces 32

33 Sections: 2d landscapes -surfaces 33

34 Sections: 2d landscapes -surfaces 34

35 Sections: 2d landscapes -surfaces 35

36 Sections: 2d landscapes -surfaces 36

37 Sections: 2d landscapes -surfaces 37

38 Sections: 2d landscapes -surfaces 38

39 Sections: 2d landscapes -surfaces 39

40 Sections: 2d landscapes -surfaces 40

41 Quantum control trajectories Generation

42 An evolutionary algorithm at work: visualization of adaptive optimization on a control landscape Optimizing for the upper target channel J. Phys. B., 41, , (2008) 42

43 J. Photochem. Photobiol. A, 180, 248, (2006) Control of ultrafast molecular dynamics Atoms Molecules The experiment on K 2 molecules 795 nm, 30 fs

44 SPODS on molecules: experimental setup J. Phys.: Conf. Ser., 88, , (2007)

45 J. Phys.: Conf. Ser., 88, , (2007) Control via phase and intensity intensity = 2 x W/cm 2 phase

46 Conclusion Optimization of strong-field control Open-loop and closed-loop control on a model system Pulse parameterization based on physical insights Experimental quantum control landscapes Physical insights from of optimal pulses: e.g. MultiRAP Adaptive optimization on a landscape: control trajectories Insights from the structure of 3d control landscapes SPODS is a general scheme for strong field control: experimental demonstration on molecules 46