Frontières et défis de l'optique non-linéaire
nouveaux guides d’ondes, nouvelles non linéarités,
nouvelles directions …
John Dudley
CNRS Institut FEMTO-ST
Université de Franche-Comté
Besançon, France
Workshop INSIS - Optique électromagnétique
Mardi 2 décembre 2014
Nonlinear optics and lasers are natural partners
The high power and spatial coherence of laser light enabled the study of
the nonlinear response of light to optical fields
1960
1961
(the first evidence of the second harmonic was removed as a speck of dirt)
Nonlinear optics and lasers are natural partners
The high power and spatial coherence of laser light enabled the study of
the nonlinear response of light to optical fields
1960
1961
(the first evidence of the second harmonic was removed as a speck of dirt)
The uses of nonlinear optics
Does this mean that nonlinear optics has only very few applications?
E. Garmire, Nonlinear Optics in Daily Life, Optics Express 21 30532 (2013)
The uses of nonlinear optics
Nonlinear Optics
Fundamental
Science
Source
Development
Applications in
Materials
Information
Technology etc
…
New Wavelengths
Machining
Amplifiers
Ultrafast lasers
Spectroscopy
Soliton-like pulses
Frequency Combs
Analytical Tools
Sensors
…
…
…
Nonlinearity is often embedded within optical systems and applications
E. Garmire, Nonlinear Optics in Daily Life, Optics Express 21 30532 (2013)
A selection of topics
• Where is nonlinear optics useful today?
•
•
•
Supercontinuum and applications
Telecommunications
Source development
Other areas of physics
• Towards true nanoscale nonlinear optics
Nanoscale material processing
Proof of principle results
Challenges
• Where is nonlinear optics useful today?
1960’s saw low-loss optical waveguide development
• Reliable techniques for fabricating small-core waveguides allows tailored
linear guidance (dispersion) and controlled nonlinear interactions
Submarine cables
www.submarinecablemap.com
The need for disruptive photonic technologies
Bandwidth
Catastrophe
Solution: all-optical integration and functionality
Basic communication system
SOURCE
MODULATOR DETECTOR
Propagation control
New optical waveguides
Nonlinear functionalities
Optical
response
A Hype Cycle of Nonlinear Optics
Low loss waveguides, new materials
Nonlinear Solutions to every problem
Peak of Hype
RESEARCH
Practical sources
Alternative solutions
Hard Work, Realism
Nonlinearity
Trigger
Limited real world use
Depths
of Despair
TIME
…
A Hype Cycle of Nonlinear Optics
Low loss waveguides, new materials
Nonlinear Solutions to every problem
Peak of Hype
New Trigger
RESEARCH
Practical sources
Alternative solutions
Hard Work, Realism
Nonlinearity
Trigger
Limited real world use
Depths
of Despair
TIME
New waveguides enable other possibilities
The mid 1990’s saw the development of micro (then nano) structured
waveguides with the ability to engineer nonlinearity and dispersion
Nonlinear effects now observed
using a wider range of sources
Match wavelengths of source &
waveguide zero dispersion
The effects observed were unexpected …
The effects observed were unexpected …
(Note on history)
• Russell’s initial idea was to create a photonic bandgap guidance
mechanism in contrast to the refractive index guidance mechanism
1991
• The first fibers they tried to make failed to show a photonic bandgap, but
they tested them anyway, and discovered the fact that the microstructure
provided new possibilities to engineer refractive index guidance
Nonlinear pulse propagation
Polarization contains linear and nonlinear components
In fibres we are concerned with nonlinear polarization from c(3)
Neglecting third harmonic generation yields :
intensity-dependent refractive index n(I) = n0 + n2 I
Modelling the supercontinuum is more complex
We use a generalized nonlinear Schrödinger equation (NLSE)
Linear dispersion
Self-steepening
Physics: NLSE + perturbations
Three main processes
Soliton ejection
Raman – shift to long l
Radiation – shift to short l
SPM, FWM, Raman
Modelling agrees with experiment !!
We use a generalized nonlinear Schrödinger equation (NLSE)
Linear dispersion
Self-steepening
SPM, FWM, Raman
Three main processes
Soliton ejection
Raman – shift to long l
Radiation – shift to short l
Spectrum (20 dB/div)
Physics: NLSE + perturbations
Output Spectra
Experiment
Simulation
Wavelength (nm)
Ultrafast nonlinear fiber optics
Basic description of ultrashort pulses
An octave-spanning spectrum allows
comb position to be readily stabilized
We can bridge the gap between a known
optical frequency locked to definition of
the second and any optical frequency
Frequency combs find very wide use
Example: planetary discovery
Periodic Doppler shift of stellar spectral lines is perturbed by planetary motion
Astrocombs measure radial
velocity changes of ~ 10 cm/s
Who would have predicted this ?
Example: broadband light source
Molecular fingerprinting
Human breath analysis
S. Diddams et al. Nature 445, 627 (2007)
M. J. Thorpe et al. Opt. Express 16, 2387 (2008)
Supercontinuum applied in Terabit/s telecommunications
Here, the nonlinear optics is enabling but the real breakthrough is the system
D. Hillerkuss et al.
Supercontinuum is used for broad spectrum for spectral slicing and OFDM
Materials
New materials enable progress to-mid infrared
Organic fingerprint region – gas sensing, medicine, food analysis etc
Nonlinear optics in gas-filled fibres enables UV
The ability to pressure-tune dispersion in
hollow core fibres enables gas-phase
nonlinear optics
Hollow-core photonic crystal fibres for gas-based nonlinear optics, Nat Photon 8, 278–286 (2014)
Nonlinear optics is central to fs source development
Exploiting and managing nonlinearity is critical in the design of a wide
range of femtosecond sources in many different application regimes
W Sibbett et al. The development and application of femtosecond laser systems
Optics Express Focus Issue on Modular Ultrafast Lasers 20 6989-7001 (2012)
Nonlinear optics is central to fs source development
Nonlinear saturable absorption is a key component of pulsed lasers
Optical “toy models” for other physical systems
Nonlinear wave evolution in fiber and on deep water are described by the same
nonlinear propagation model
Rogue waves – rare and extreme surface waves
Rogue Waves are extreme events appearing seemingly from nowhere
•
Ocean Waves
•
Optics
1974
1995
Kherif et al. Rogue Waves in the Ocean, Springer (2009)
Dudley et al. Nature Photonics 8, 755-764 (2014)
Now influencing research in fluid mechanics
Rogue Waves in a Water Tank
Chabchoub et al. Phys. Rev. Lett. 106 204502 (2011)
• Towards truly nanoscale nonlinear optics
Nonlinear optics of permanent material modification
Gatass, R. and Mazur, E. Nature Photonics 2,219 (2008)
Gaussian beams cannot penetrate deeply in materials
Tradeoff between interaction length and intensity
Gaussian beams have an unavoidable
tradeoff between interaction length
and focal spotsize and power density
Femtosecond ablation for machining
extended channels is a difficult technology
White,Y. et al, Opt. Express
16,14411 (2008)
Enhanced interaction lengths also possible in free space
The spatial phase of femtosecond Gaussian beams can be tailored to
yield important classes of non-diffracting and accelerating beams
Non-diffracting Bessel Beams
J. Durnin et al.
Phys. Rev. Lett. 58 1499 (1987)
Accelerating Airy Beams
M. V. Berry and N. L. Balazs
Am. J. Phys. 47 264 (1979)
G. A. Siviloglou et al.
Phys. Rev. Lett. 99 213901 (2007)
New possibilities for micro and nano structuring
High aspect ratio channels
using Bessel beams
Advanced surface machining using
accelerating and vortex beams
Graphene
10 mm
Expt
High aspect ratio nanochannels
Sending fs pulses in circles
Machining diamond and silicon
Vortex Bessel beams in graphene
M. Bhuyan et al. Appl. Phys. Lett. 97 081102 (2010)
F. Courvoiser et al. Opt. Lett. (April 2012)
A. Mathis et al. Appl. Phys. Lett. 101, 071110 (2012)
B. Wetzel et al. Appl. Phys. Lett. 103, 241111 (2013)
New materials enable progress to nanoscale
Theoretical challenges
Major
Linear dispersion
1.
2.
3.
4.
5.
Input pulse is a high-order soliton
Perturbation due to proximity to ZDW
Break up into fundamental solitons
Soliton dynamics - Raman self-frequency shift (RED)
Soliton dynamics - Dispersive wave generation (BLUE)
Minor
SPM, FWM, Raman
Characterisation challenge
Time resolved near-field microscopy needs to become an easy technology!
Metamaterials, plasmonics
Enhanced SHG
Nonlinear phase modulation
Fano resonances
Bistability
Metamaterial NLSE
Allan Boardman
Opt. Commun. 283 1585 (2010)
Solitons
Parametric amplification
Raman scattering
Phase conjugation
Wavelength conversion
Where are we today with nonlinear nanophotonics?
Low loss waveguides, new materials
Nonlinear Solutions to every problem
Peak of Hype
RESEARCH
Practical sources
Alternative solutions
Hard Work, Realism
Nonlinearity
Trigger
Limited real world use
Depths
of Despair
TIME
…