About the Arrival and the Role of the Laser

Transcription

1 38th International Nathiagali Summer College on Physics and Contemporary Needs 02. July 2013 D. Meschede, Institut für Angewandte Physik, Universität Bonn

2 Der Laser turned 50 in 2010! fascinating light

3 1964 Spaceship Enterprise 1951 The Day the Earth Stood Still

4 My claim: The laser is a prime and beautiful example of the complex interplay of technology and curiosity driven research My hope: This talk offers outsiders and insiders interesting, perhaps inspiring aspects ranging from the history of ideas to their present impact on societies

5 I The Laser and Energy II The Laser intellectual challenge or technological imperative? III The century of the photon ahead?

6 I The Laser and Energy II The Laser intellectual creation or technological imperative? III The century of the photon ahead?

7 What are special laser properties? (more precisely: laser light) Laser light concentrates energy in space (collimation, focusability) in time (ultra short pulses) im frequency space (single color) (idea by D. von der Linde, 2010)

8 Suns, Lamps, Lasers (engl.) (dt.) What distinguishes laser light from candle light?

9 Concentration in space focusability Monochromaticity interferometry, diffraction contains and carries information Concentration in time pulsed lasers

10 focusability Antoine-Laurent de Lavoisier ( ) Musée des Arts et Métiers, Paris

11 monochromaticity

12 concentration in time

13 I The Laser and Energy II The Laser intellectual challenge or technological imperative? III The century of the photon ahead?

14 Short detour: the origin of quantum physics 1887: PTR Berlin opens W. v. Siemens, H. v. Helmholtz 1888: optics laboratory opens The route to quantum physics was strongly influenced by the quest for efficient lighting!

15 1900:Planck s Quantum Physics 2000:COBE/WMAP & Lasers

16 one of the idea generators 1912

17 inversion! concepts

18 Albert Einstein had in 1905 two indications, that light fields have quantum character - Planck s radiation law - the photo electric effect developed in 1917 the concept of - stimulated emission Stimulated emission is the foundation of light amplification leading to the laser.

19 Radiative Processes (stimulated) absorption stimulated emission

20 The laser might have happened earlier.,,negative Dispersion of a neon discharge 633,4 W. Lamb A. Kastler H. Kopfermann R. Ladenburg, H. Kopfermann, 1928 Kaiser-Wilhelm-Institut für phys. Chemie, Berlin-Dahlem (now MPG) Nature 122, 438 (1928)

21 the scientific advent of the laser --- a matter of schools? (example: USA and Germany) Columbia University New York I. I. Rabi W. Lamb C. Townes A. Schawlow Hamburg Göttingen O. Stern M. Born R. J. Oppenheimer H. Sponer J. Franck H. Maier-Leibnitz R. Mößbauer H. Kopfermann H. Dehmelt, W. Paul General Electric MIT/Lincoln IBM Bell Laboratories 1960 numerous further scientific descendants e.g. H. Walther, P. Toschek, T.W. Hänsch, G. Werth, R. Blatt, E. Otten, W. Ketterle, D.M. numerous german physicists, e.g. W. Kaiser, H. Welling and others = nobel prizes = laser pioneer

22 Most (non-)physicists consider the laser an optical device But: Optical research did not advance the creation of coherent (i.e. phase stable) light sources. Progress was obtained with electronic oscillators: AC currents valve oscillator magnetron maser laser The,,classic scientific conference for laser physicists is called International Conference on Quantum Electronics (IQEC)

23 Radar = Radio Detection and Ranging Needs short (cm) waves Needs transparent atmosphere Radar window

24 3G: n = 2,1 GHz l = 14 cm magnetron of a microwave oven n = 2,45 GHz, l = 12,2 cm

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26 . oh and I said we ve got to work on the war and you must do engineering and do RADAR. Oh dear. I didn t want to do engineering, I wanted to do physics. and I thought Why hadn t we been able to come up with an idea of how do we produce short waves? Electronic devices just couldn t produce short waves, just couldn t react fast enough, to oscillate fast enough. Well, I said, molecules and atoms produce short waves but C. Townes in the interview published by LASERFEST, Optical Society of America

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28 The race for the laser was started in 1958:

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31 lasing! racing

32 The Winner:

33 Nature 187, (1960) rejected by Phys. Rev. Lett.

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35 What is the signature of laser radiation?

36 (from left to right) with the first Helium-Neon-Laser (Bell Laboratories) 1961

37 Patent War

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39 Schawlow-Townes-Patent Townes: revenue occasionally 2-3 times his annual salary as a professor, but mostly paid to the Research Foundation of Columbia University Gould-Patent revenue of the last year 7,5 Mio $ (late award was very profitable!)

40 Economic Development Laser Technology Physics World Mai 2010 Now: ~ 6-8 Billion $/year Further sales: > 600 Billion $/year

41 A crucial moment: R. Hall and team admire the cryostat with the first ever laser diode, GE 1962

42 2012: 50 years of diode lasers

43 But why did it take till ~ 1985 to start their success?

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46 Ideal case: convert every electron/hole pair into a photon

47 lasers need high inversion density, not only inversion!

48 Z. Alferov, H. Kroemer, 2000

49 Physics World May 2010

50 white is composed from RGB

51 advantageous: convert current into light! The author of a scientific fairy tale (~ 1990) Shuji Nakamura, UC Santa Barbara formerly Nichia Chemicals, Japan GaN shines blue! Times Square 1998

52 Remark: See your hardware store and try to understand lighting devices

53 I The Laser and Energy II The Laser intellectual challenge or technological imperative? III The century of the photon ahead?

54 you wouldn t guess Concentration in space focusability Concentration in time pulsed lasers Monochromaticity interferometry, diffraction contains and carries information

55 You wouldn t guess

56 Concentration in space focusability

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58 Lasers for mechanical engineering Optoelectronics Report 16 3 (2009)

59 Fibers are a means to build especially elegant lasers (mit frdl. Erlaubnis, A. Tünnermann)

60 Therapy: With laser beams the LASIK-method allows to correct the cornea

61 Concentration in time pulsed lasers

62 laser stroboscopes: short, ultra short, atto short Sibbett s laser, CPA With thanks to D. v. d. Linde, Essen

63 The Pulse duration intensity conjecture: Pulse duration ~ 1 intensity

64 ELI = European Light Infrastructure George Mourou s invention: Chirped Pulse Amplification (CPA)

65 Monochromaticity interferometry, diffraction contains and carries information

66 diode lasers any sort of communication (Optoelectronics Report 16 3 (2009)

67 diode lasers and IT

68 In optical fibers the light wave is guided by total internal reflection optical fibers are the backbone of our (world wide) communication technology

69 E. Desurvire, Southampton Without repeater amplifiers no long distance communication! hauling opt. overseas cables repeater amplifier for opt. long distance link

70 Physical conditions: - extremely low loss glass fibers - all-optical fiber amplifiers (EDFAs) -.

71 diode laser und datacom (interconnects)

72 About half of the fastest super computers were built by IBM Now all of them use optical interconnects Mare Nostrum uses 5000 parallel opt. fiber links GB/s/ch

73 optical interconnects: relevant parametres are speed, weight, and foot print IBM Announcement: Exaflop Computer, > 2016 several billion (optical) interconnects at 20 mw/ emitter: > 20 MW power consumption

74 Shortly, the datalink market will be dominated by optical technologies 100 G Ethernet Dank an D. Bimberg, Berlin

75 Lasers/Optics/Photonics will have (more) significant applications in data links and communication technology in medical diagnosis and therapy in sensor applications in process control in lighting technologies. laser generated photons will be an ubiquitious commodity much like electrons!