ultrafast lasers - introduction | dautreppe.photonique...
TRANSCRIPT
Laboratoire Temps – Fréquence (LTF)
Thomas Südmeyer Time/Frequency Laboratory, Physics Institute, University of Neuchatel Grenoble, Dautreppe 2015 Photonique, 7. Dec. 2015
Ultrafast lasers
Laboratoire Temps – Fréquence (LTF) 7.12.2015
Laboratoire Temps – Fréquence (LTF)
What is ULTRAFAST?
Laboratoire Temps – Fréquence (LTF)
Ultrafast laser pulses
Access ultrashort time scales
Broad optical spectrum
Concentrate in time and space
Laboratoire Temps – Fréquence (LTF)
Resolving fast events
Cinema: time between images 124 Hz
= 42 ms
Laboratoire Temps – Fréquence (LTF)
The horse in motion
Baronet, 1794
www.wikipedia.org
George Stubbs (1724-1806): English painter, best known for his paintings of horses.
Whistlejacket, 1762
Laboratoire Temps – Fréquence (LTF)
Fast mechanical shutter photography E. Muybridge in 1878: understand horse gallop using fast photography in the ms-domain
Laboratoire Temps – Fréquence (LTF)
Fast mechanical shutter photography E. Muybridge in 1878: understand horse gallop using fast photography in the ms-domain
Laboratoire Temps – Fréquence (LTF)
Fast flash photography Harold E. Edgerton (1903-1990): understand fast processes using flash light (limited by duration of flashes to µs-domain)
Laboratoire Temps – Fréquence (LTF)
Fast flash photography Harold E. Edgerton (1903-1990): understand fast processes using flash light (limited by duration of flashes to µs-domain)
Laboratoire Temps – Fréquence (LTF)
Fast flash photography Harold E. Edgerton (1903-1990): understand fast processes using flash light (limited by duration of flashes to µs-domain)
Laboratoire Temps – Fréquence (LTF)
Fast flash photography Harold E. Edgerton (1903-1990): understand fast processes using flash light (limited by duration of flashes to µs-domain)
Laboratoire Temps – Fréquence (LTF)
Femtochemistry by A. H. Zewail in 1994 A. H. Zewail in 1994: understand transition states in chemical reactions using fs-pulses
http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1999/illpres/reaction.html
Laboratoire Temps – Fréquence (LTF)
Femtochemistry by A. H. Zewail in 1994 A. H. Zewail in 1994: understand transition states in chemical reactions using fs-pulses
Laboratoire Temps – Fréquence (LTF)
Scales
picosecond 10–12 s
femtosecond 10–15 s
nanosecond 10–9 s
Time
Laboratoire Temps – Fréquence (LTF)
Scales
The Lunar Laser Ranging Experiment from the Apollo 11 mission
A laser beam from the Apache Point Observatory heads toward the moon
𝟑𝟑𝟑𝟑𝟑𝟑𝟑𝟑𝟑𝟑𝟑𝟑 𝐤𝐤𝐤𝐤𝒄𝒄
= 𝟏𝟏.𝟐𝟐𝟐𝟐 𝒔𝒔
Laboratoire Temps – Fréquence (LTF)
A 5 fs pulse
Electric field 𝐸𝐸𝑥𝑥(𝑟𝑟0, 𝑡𝑡)
Time t
2.7 fs =wavelength
𝑐𝑐=
800nm𝑐𝑐
Laboratoire Temps – Fréquence (LTF)
A 5 fs pulse
speed of light
𝟐𝟐 𝐟𝐟𝐟𝐟 ⋅ 𝒄𝒄 = 𝟏𝟏.𝟐𝟐 µ𝒎𝒎
Distance y
Distance z
Distance x
Laboratoire Temps – Fréquence (LTF)
Ultrafast laser pulses
Observe and use fast dynamics • understand chemical reaction dynamics • fast communication • …
Access ultrashort time scales
interconnects optical clocking
Laboratoire Temps – Fréquence (LTF)
Ultrafast laser pulses
Observe and use fast dynamics • understand chemical reaction dynamics • fast communication • …
Access ultrashort time scales
Broad optical spectrum
Laboratoire Temps – Fréquence (LTF)
Key advantage of laser light: coherence
Spatial coherence Propagation over long distances & reduced divergence…
… or extremely small spot & high divergence
Laboratoire Temps – Fréquence (LTF)
Key advantage of laser light: coherence
Long duration and very small spectrum …
… or short pulses and wide spectrum
⇒ Ultrafast lasers and frequency combs!
Spatial coherence Temporal coherence Propagation over long distances & reduced divergence…
… or extremely small spot & high divergence
Laboratoire Temps – Fréquence (LTF)
Continuous-wave laser
Light circulates in resonator
Losses compensated by gain in laser medium (which is externally pumped)
Gain saturates to a level that it compensates the losses
Light emission typically continuous
Laboratoire Temps – Fréquence (LTF)
Passively modelocked laser
Short pulse circulates in cavity (fs-ps)
High repetition rate pulse train at the output (MHz-GHz)
Pulse formation process initiated and stabilized by saturable absorber in the laser cavity
Steady-state pulse parameters: governed by interplay of gain, (saturable) loss, dispersion, Kerr nonlinearity, etc.
Saturable loss
Laboratoire Temps – Fréquence (LTF)
Modelocking and frequency combs
http://www.physik.uni-wuerzburg.de/femto-welt/pulsframe.html
Laboratoire Temps – Fréquence (LTF)
Saturable absorber modelocking
Animation: http://www.rp-photonics.com/mode_locking.html
Laboratoire Temps – Fréquence (LTF)
Time, light, and extreme precision
Laboratoire Temps – Fréquence (LTF)
From: T. Hänsch, „A passion for precision“, Nobel Lecture, Stockholm 2005
𝟏𝟏𝟏𝟏𝟏𝟏 𝐩𝐩𝐟𝐟𝟏𝟏 𝐝𝐝𝐝𝐝𝐝𝐝
Time, light, and extreme precision
≈ 𝟏𝟏𝟏𝟏−𝟏𝟏𝟐𝟐
Laboratoire Temps – Fréquence (LTF)
The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.
http://www.bipm.org/fr/si/si_brochure/chapter2/2-1/2-1-1/second.html www.wikipedia.org http://hyperphysics.phy-astr.gsu.edu/hbase/images/csclock.gif
Time, light, and extreme precision
Laboratoire Temps – Fréquence (LTF)
Scales
http://www.earth-time.org/trollart.html www.wikipedia.org
Laboratoire Temps – Fréquence (LTF)
Scales
http://www.earth-time.org/trollart.html www.wikipedia.org
Formation of moon 𝟑𝟑𝟐𝟐𝟏𝟏𝟏𝟏 𝐤𝐤𝐦𝐦𝐦𝐦𝐦𝐦𝐦𝐦𝐦𝐦𝐦𝐦 𝐝𝐝𝐲𝐲𝐝𝐝𝐲𝐲𝐟𝐟 ∙ 𝟏𝟏𝟏𝟏−𝟏𝟏𝟐𝟐
= 𝟏𝟏𝟑𝟑𝟐𝟐 𝐟𝐟𝐲𝐲𝐬𝐬𝐦𝐦𝐦𝐦𝐝𝐝𝐟𝐟
Laboratoire Temps – Fréquence (LTF)
Scales
http://www.earth-time.org/trollart.html www.wikipedia.org
Extinction of dinosaurs 65 𝐤𝐤𝐦𝐦𝐦𝐦𝐦𝐦𝐦𝐦𝐦𝐦𝐦𝐦 𝐝𝐝𝐲𝐲𝐝𝐝𝐲𝐲𝐟𝐟 ∙ 𝟏𝟏𝟏𝟏−𝟏𝟏𝟐𝟐 = 𝟐𝟐 𝐟𝐟
Laboratoire Temps – Fréquence (LTF)
From: T. Hänsch, „A passion for precision“, Nobel Lecture, Stockholm 2005
𝟏𝟏𝟏𝟏𝟏𝟏 𝐩𝐩𝐟𝐟𝟏𝟏 𝐝𝐝𝐝𝐝𝐝𝐝
Time, light, and extreme precision
≈ 𝟏𝟏𝟏𝟏−𝟏𝟏𝟐𝟐
Laboratoire Temps – Fréquence (LTF)
Time, light, and extreme precision
From: T. Hänsch, „A passion for precision“, Nobel Lecture, Stockholm 2005
Laboratoire Temps – Fréquence (LTF)
Oscillators
Oscillator: repetitive movement
Counter: measure time in practical units
Pendulum: Quartz resonator: Microwave resonator: Typical optical atomic transition:
~ 1 osc/sec ~ 1’000’000 osc/sec
~ 10’000’000’000 osc/sec ~ 100’000’000’000’000 osc/sec
Laboratoire Temps – Fréquence (LTF)
Oscillators
Oscillator: repetitive movement
Counter: measure time in practical units
Pendulum: Quartz resonator: Microwave resonator: Typical optical atomic transition:
~ 1 osc/sec ~ 1’000’000 osc/sec
~ 10’000’000’000 osc/sec ~ 100’000’000’000’000 osc/sec
How to count?
Laboratoire Temps – Fréquence (LTF)
the basic time unit in the SI system
an optical frequency standard
Previous measurements of absolute optical frequencies
Laboratoire Temps – Fréquence (LTF)
the basic time unit in the SI system
an optical frequency standard
a heroic frequency chain
Previous measurements of absolute optical frequencies
Laboratoire Temps – Fréquence (LTF)
the basic time unit in the SI system
an optical frequency standard
a heroic frequency chain
Previous measurements of absolute optical frequencies
a single frequency
comb laser
Laboratoire Temps – Fréquence (LTF)
Frequency combs
optical
microwave
Revolution in metrology: stabilization of frequency combs! Allows to compare microwaves with optical frequencies ⇒ Nobel price 2005: T. W. Hänsch, J. L Hall
Phase-stable link between optical and microwave frequencies
Fs-laser based frequency combs
Unknown frequency
Laboratoire Temps – Fréquence (LTF)
H. Telle et al., Appl.Phys. B 69, 327 (1999)
CEOCEOf
tϕ∂
=∂
Carrier Envelope Offset (CEO)
http://www.rp-photonics.com/img/ceo.gif
Laboratoire Temps – Fréquence (LTF)
CEO stabilization
Laboratoire Temps – Fréquence (LTF)
H. Telle et al., Appl.Phys. B 69, 327 (1999)
Octave spanning supercontinuum required (typically achieved by coherent spectral broadening in highly-nonlinear fiber)
Detection of the CEO-phase change No direct measurement possible Indirect f-to-2f-measurement scheme
CEOCEOf
tϕ∂
=∂
CEO detection in the f-2f scheme
Laboratoire Temps – Fréquence (LTF)
Artist’s rendering of JILA’s molecular fingerprinting system
http://patapsco.nist.gov/ImageGallery/details.cfm?imageid=842
Baxley/JILA
Laboratoire Temps – Fréquence (LTF)
Dual comb spectroscopy
Laboratoire Temps – Fréquence (LTF)
Astrocomb
http://www2.mpq.mpg.de/~haensch/comb/Astrocomb/english.html
T. Steinmetz, T. Wilken, C. Araujo-Hauck, R. Holzwarth, T. W. Hänsch, L. Pasquini, A. Manescau, S. D’Odorico, M. T. Murphy, T. Kentischer, W. Schmidt, T. Udem, “Laser frequency combs for astronomical observations,” Science 321, 1335–1337 (2008)
Laboratoire Temps – Fréquence (LTF)
Yb-lattice atomic clock
Laboratoire Temps – Fréquence (LTF)
Ultrafast laser pulses
Observe and use fast dynamics • understand chemical reaction dynamics • fast communication • …
Access ultrashort time scales
Broad optical spectrum
Generate ultrastable frequency combs • high precision spectroscopy • optical clocks • …
Laboratoire Temps – Fréquence (LTF)
Ultrafast laser pulses
Observe and use fast dynamics • understand chemical reaction dynamics • fast communication • …
Access ultrashort time scales
Broad optical spectrum
Generate ultrastable frequency combs • high precision spectroscopy • optical clocks • …
Concentrate in time and space
Laboratoire Temps – Fréquence (LTF)
Ultrafast lasers: material processing
Picture: Stefan Nolte
Laboratoire Temps – Fréquence (LTF)
Ultrafast lasers: material processing
https://www.youtube.com/watch?v=S_8nD4OuwX4
Laboratoire Temps – Fréquence (LTF)
Ultrafast lasers: material processing
Laboratoire Temps – Fréquence (LTF)
Ultrafast lasers: material processing
https://www.youtube.com/watch?v=AD2Oqg0Pnq0
Laboratoire Temps – Fréquence (LTF)
Ultrafast lasers: material processing
https://www.youtube.com/watch?v=5VfCiqRWbeA
Laboratoire Temps – Fréquence (LTF)
Ultrafast laser market
Laboratoire Temps – Fréquence (LTF)
pulse energy
repetition rate average power ( = Ep frep) pulse duration
peak power ( ∝EP / τP )
Ep
frep Pave
τp Ppeak
𝜆𝜆 Δ𝜆𝜆
time domain TR = 1 / frep
τp
Key parameters of ultrafast lasers
wavelength optical bandwidth
Laboratoire Temps – Fréquence (LTF)
Frontier: average power and pulse energy
High energy and MHz
T. Südmeyer, et al., “Femtosecond laser oscillators for high-field science”, Nature Photonics 2, 559 (2008)
Industrial applications • increase throughput, • reduce costs per item, …
Scientific applications
• reduce measurement time, • increase signal-to-noise, • MHz XUV sources, …
Nolte, et al., Adv. Eng. Mater. 2, 2000
Laboratoire Temps – Fréquence (LTF)
Key for high average power: heat removal ⇒ High surface-to-volume ratio
Fiber Slab Thin disk
High average power ultrafast sources
Laboratoire Temps – Fréquence (LTF)
Key for ultrafast: reduce nonlinearities, avoid damage
High average power ultrafast sources
http://www.amazon.de/Supercontinuum-Generation-Optical-Fibers-Dudley/ http://lidaris.com/glossary-2/laser-induced-damage-morphology/
⇒ Reduce peak intensity ⇒ Reduce interaction volume
Laboratoire Temps – Fréquence (LTF)
A. Giesen, et al., Appl. Phys. B 58, 365 (1994)
- Use in reflection: efficient heat removal through back side
- 1D longitudinal heat flow → reduced thermal lensing
- Power scalable by increase of mode diameter D (constant intensities)
Thin disk laser
Laboratoire Temps – Fréquence (LTF)
Highest average powers and highest energies of any ultrafast oscillator technology
Ep = 80 μJ
τp = 1.07 ps frep = 3 MHz Pav = 242 W
Ep = 17 µJ Pav = 275 W τp = 583 fs frep = 16.3 MHz
C.J. Saraceno, et al., Optics Express 20, 23535 (2012)
SESAM Modelocked Thin Disk Lasers
Laboratoire Temps – Fréquence (LTF)
Modelocked thin disk laser
Animation by Martin Hoffmann
Laboratoire Temps – Fréquence (LTF)
Harnessing intracavity nonlinearities
Laboratoire Temps – Fréquence (LTF)
Key for ultrafast: reduce nonlinearities • Operation at reduced peak intensity • Reduced interaction volume
Chirped Pulse Amplification (CPA)
Dispersion
Laboratoire Temps – Fréquence (LTF)
Chirped Pulse Amplification (CPA)
https://en.wikipedia.org/wiki/Chirped_pulse_amplification
Laboratoire Temps – Fréquence (LTF)
Chirped pulse amplification (CPA) in a fiber: 830 W, 640 fs
T. Eidam, et al., Optics Letters 35, 94-96 (2010)
Laboratoire Temps – Fréquence (LTF)
osci
llato
rs
amplifiers
Towards powerful MHz ultrafast laser sources
Chirped pulse amplification 830 W, 640 fs, 78 MHz
Innoslab amplifier 1.1 kW, 615 fs, 20 MHz P. Russbueldt, et al., Opt. Lett. 35 (2010) T. Eidam, et al., Opt. Lett. 35 (2010)
Thin disk multipass amplifier 1.4 kW, 7.7 ps, 300 kHz
Thin disk oscillators 275 W, 580 fs, 17 MHz
J. P. Negel, et al., Opt. Lett. 38 (2013)
C.J. Saraceno, et al., Optics Express 20 (2012)
Laboratoire Temps – Fréquence (LTF)
High energy CPA systems: National Ignition Facility
Laboratoire Temps – Fréquence (LTF)
National Ignition Facility: towards laser-based fusion
https://www.youtube.com/watch?v=yixhyPN0r3g
Laboratoire Temps – Fréquence (LTF)
What is ULTRAFAST?
Laboratoire Temps – Fréquence (LTF)
National Ignition Facility: towards laser-based fusion
N I F WARP CORE https://www.youtube.com/watch?v=wdD5M3Vtdh0
Laboratoire Temps – Fréquence (LTF)
Ultrafast laser pulses
Observe and use fast dynamics • understand chemical reaction dynamics • fast communication • …
Access ultrashort time scales
Broad optical spectrum
Generate ultrastable frequency combs • high precision spectroscopy • optical clocks • …
Concentrate in time and space Achieve extremely high intensities • material processing, eye surgery, … • biomedical imaging, …. • high field science, …
Laboratoire Temps – Fréquence (LTF)
Thank you for your
attention !
Ultrafast laser pulses