Attosecond Control and Measurement: Lightwave Electronics

More documents

Recommendations

Info

1 . 3 AT T O S E C O N D A N D H I G H - F I E L D P H Y S I C S D I V I S I O N electrons and ions) for a range of applications in physics and life sciences. Each of these areas builds upon strong synergies between theoretical and experimental research and is based on a number of collaborations with groups from all over the world. The facilities of our LMU-MPQ joint laboratory are situated at MPQ and the LMU Physics Building at Coulombwall 1. LAP members working at both locations closely co-operate, forming a single coherent group with weekly meetings, discussions and intense communications on a daily basis. 1.3.1.1 PUShING ThE FRONTIERS OF FEMTOSECOND TEChNOlOGY Attosecond technology is based upon and has grown out of femtosecond technology. Improving femtosecond technology towards (i) bandwidths approaching, reaching, and exceeding an octave, (ii) intense pulses at higher (MHz) repetition rates, i.e. higher average powers, (iii) higher peak powers both at kilohertz as well as 10 Hertz repetition rates and endowing it with (iv) carrier-envelope phase stabilization constitute basic requirements for advancing attosecond technology. Advances (i) and (iv) enable researches to generate intense laser pulses with stabilized waveform. Strongfield (multi-photon-assisted) interaction of these waveform-stabilized pulses with matter has provided access to the value of their carrier-envelope phase [3], allowing the determination and thereby full control of their waveform. We dub the sources of these waveform-controlled few-cycle light pulses light waveform synthesizers and consider them as the major technological pillars of attosecond science. Increasing their bandwidth (i) improves attosecond metrology by generating shorter isolated attosecond pulses with higher efficiency (see next chapter). Increasing their pulse repetition rate into the MHz regime (ii) opens the door for endowing coincidence spectroscopy with attosecond temporal resolution. Last but not least, increasing their peak power to the multi-terawatt regime (iii) is the prerequisite for extending attosecond control to relativistic electrons. BROADBAND ChIRPED DIElECTRIC MUlTIlAYER MIRRORS constitute an enabling technology for all these developments: they are the only optical components capable of providing dispersion control (i) over bandwidths required for shaping optical waveforms within the wave cycle, (ii) with extremely low loss required for high-averagepower MHz-rate femtosecond pulse generation in high-Q laser resonators and passive build-up cavities, (iii) with low amount of material withstanding high intensities, making them ideal for tailoring, steering and focusing ultrabroad-band, multiterawatt pulses. Therefore we continue – even some 15 years after its invention [18] – our efforts to advance this technology. In collaboration with A. V. Tikhonravov and M. K. Trubestkov from Moscow State University, Vladimir Pervak and Alexander Apolonskiy have developed a family of dispersive mirrors for precision dispersion control over an octave or more in the visible (VIS), nearinfrared (NIR) spectral range for widespread use in LAP’s ultrafast laser “workhorses” (see next section). With MAP Service Center’s newly-installed electron-beam evaporation system, the team has recently succeeded in the first realization of a chirped multilayer dielectric mirror providing dispersion control over the spectral range of 300-900 nm and the first use of hafnium oxide in a chirped mirror [19]. Simultaneously, the chirped mirror technology is being extended to the mid IR (MIR) up to wavelengths of 3 μm. Precision dispersion metrology via white light interferometry is also being extended to the same spectral range (from MIR to UV). These developments allow extension of broadband dispersion control to a spectral range spanning several octaves, paving the way towards the generation of mono-cycle to sub-cycle optical waveforms and arbitrary optical waveform synthesis, as well as towards frequency combs over the UV-VIS-NIR-MIR spectral range. Moreover, hafnium-oxide-based chirped mirrors will lead to high-damage-threshold broadband optics for high-power applications. lIGhT WAVEFORM SYNThESIZERS constitute key tools for attosecond science. Thanks to ongoing advances in chirped multilayer technology, we can now reliably generate intense (sub-terawatt) sub- 1.5-cycle laser pulses in the VIS/NIR spectral range at kHz repetition rates in several workhorse laser systems on a daily basis in our laboratory. Figure 1 shows the spectrum and interferometric autocorrelation recorded by Adrian Cavalieri and coworkers, featuring clean, ~3.5fs-duration (full width at half maximum) laser pulses carried at a wavelength of ~ 750 nm (field oscillation period ~ 2.5 fs) [6,20]. This performance has recently been reproduced by Sergei Trushin, Izhar Ahmad and co-workers, and by Eleftherios Goulielmakis and Martin Schultze using other LAP laser systems, demonstrating 134 Max-Planck-Institut für Quantenoptik • Progress Report 2007/2008
A B C D E Figure 1: (A) Photo of the chirped dielectric multilayer mirrors providing high reflectivity and dispersion control over the spectral range of 450 – 1000 nm. (B) Schematic of the hollow-fibre/chirped mirror compressor seeded with carrier-envelope-phasestabilized 25-fs, 1-mJ, near-infrared laser pulses from a Ti:sapphire laser system. Spectrum (C) and interferometric autocorrelation (D) of sub-3.5-fs laser pulses carried at ~ 750 nm. (E) Possible electric field waveforms of the generated waveform-controlled sub-1.5-cycle laser pulses. 1 . 3 . 1 S U M M A R Y O F S C I E N T I F I C A C T I V I T I E S the maturity of the technology of near-single-cycle optical waveform generation. This progress had direct implication to attosecond technology as reviewed in the next chapter. The intense near-mono-cycle NIR pulses offer the potential for few-femtosecond pulse generation in the deep UV and VUV by direct harmonic conversion, or – with their different spectral components independently adjustable, in terms of both amplitude and phase – for the synthesis of a wide range of optical waveforms. Ulrich Graf and Ivanka Grguras, under the supervision of Eleftherios Goulielmakis, pursued these goals. Ulrich Graf has succeeded in generating sub-4-fs, microjoule pulses in the deep UV, at a carrier wavelength of about 250 nm by third-harmonic generation in a high-pressure neon gas cell and is now working on the extension of the technique to higher (5 th and 7 th ) harmonics and shorter pulse durations. Ivanka Grguras has set up a proto-typical 3-channel optical waveform synthesizer for the 400-1200nm spectral range using chirped, dichroic beam splitters designed, manufactured, and characterized by Vladimir Pervak and Alexander Apolonskiy. Preliminary frequency-resolved optical gating measurements of the signals transmitted through the individual channels have yielded bandwidth-limited fewcycle pulses, characterization of the overall throughput is under way. The programmable optical waveforms, once available, are expected to allow versatile steering of the atomic-scale motion of electrons in a wide range of systems. For example, they provide a large degree of freedom for controlling the electron trajectories in attosecond pulse production by high-order harmonics, offering manipulation of the generation process for different purposes (e.g. fine tuning the photon energy or optimizing the efficiency of generation). As another example, in Figure 2C(iii) a high-frequency wavepacket preceds a more slowly oscillating intense waveform, A Figure 2: (A) Chirped-mirror-based optical waveform synthesizer. Generic scheme of a multi-channel optical waveform synthesizer based on wide-band chirped dichroic beamsplitters (DBS). Max-Planck-Institut für Quantenoptik • Progress Report 2007/2008 135
Page 1 and 2: 1 S C I E N T I F I C R E P O R T S
Page 3: INTRODUCTION The motion of electron
Page 7 and 8: Building upon the preliminary work
Page 9 and 10: Figure 6: Electronic excitation and
Page 11 and 12: 1 . 3 . 1 S U M M A R Y O F S C I E
Page 13 and 14: chapter we summarize first promisin
Page 15 and 16: 1 . 3 . 1 S U M M A R Y O F S C I E
Page 17 and 18: high-resolution, low-dose cancer di
Page 19 and 20: 1.3.1.6 ATTOSECOND IMAGING Leader:
Page 21 and 22: This field, which has recently unde
Page 23 and 24: 1.3.2 SURVEY OF ThE RESEARCh ACTIVI
Page 25 and 26: 1 . 3 . 2 S U R V E Y O F T H E R E
Page 27 and 28: 1 . 3 . 2 S U R V E Y O F T H E R E
Page 29 and 30: JUNIOR RESEARCh GROUPS Dr. R. Kienb
Page 31 and 32: 432 Applied Physics B - Lasers and
Page 33 and 34: 434 Applied Physics B - Lasers and
Page 35 and 36: Vol 446 | 5 April 2007 |doi:10.1038
Page 37 and 38: Experimental set-up For a detailed
Page 39 and 40: Multi-electron relaxation As a firs
Page 41 and 42: 1 . 3 . 3 S E L E C T E D R E P R I
Page 43 and 44: that is responsible for such quantu
Page 45 and 46: electrons. This new approach is pow
Page 47 and 48: pulses at ħwcarrier ≈ 36 eV with
Page 49 and 50: Atomic physics and x-ray science. H
Page 55 and 56:
REPORTS 1614 1 . 3 . 3 S E L E C T
Page 57 and 58:
REPORTS 1616 settings selected in F
Page 59 and 60:
1 . 3 . 3 S E L E C T E D R E P R I
Page 61 and 62:
Vol 449 | 25 October 2007 | doi:10.
Page 63 and 64:
spectra integrated for 60 s at each
Page 65 and 66:
1 . 3 . 3 S E L E C T E D R E P R I
Page 67 and 68:
(which, for brevity, will be referr
Page 69 and 70:
electrons is shown in Fig. 4, as a
show all

Attosecond Control and Measurement: Lightwave Electronics

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?