Frontières et défis de l'optique non-linéairenouveaux guides d’ondes, nouvelles non linéarités,

nouvelles directions …

John Dudley

CNRS Institut FEMTO-ST

Université de Franche-Comté

Besançon, France

Mardi 2 décembre 2014Workshop INSIS - Optique électromagnétique

The high power and spatial coherence of laser light enabled the study of the nonlinear response of light to optical fields

(the first evidence of the second harmonic was removed as a speck of dirt)

Nonlinear optics and lasers are natural partners

1960 1961

The high power and spatial coherence of laser light enabled the study of the nonlinear response of light to optical fields

(the first evidence of the second harmonic was removed as a speck of dirt)

Nonlinear optics and lasers are natural partners

1960 1961

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)

Nonlinearity is often embedded within optical systems and applications

Nonlinear Optics

FundamentalScience

Source Development

Applications in Materials

Information Technology etc

New Wavelengths

Ultrafast lasers

Frequency Combs

Machining

Spectroscopy

Analytical Tools

Amplifiers

Soliton-like pulses

Sensors

The uses of nonlinear optics

… … …

…

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?

• Reliable techniques for fabricating small-core waveguides allows tailored linear guidance (dispersion) and controlled nonlinear interactions

1960’s saw low-loss optical waveguide development

Submarine cables

www.submarinecablemap.com

The need for disruptive photonic technologies

Bandwidth Catastrophe

New optical waveguides

Solution: all-optical integration and functionality

Basic communication system

Opticalresponse

Propagation control

SOURCE MODULATOR DETECTOR

Nonlinear functionalities

A Hype Cycle of Nonlinear Optics

TIMETrigger

Peak of Hype

Depths of Despair

Hard Work, Realism

Low loss waveguides, new materialsNonlinear Solutions to every problem

Limited real world useNonlinearity

RE

SE

AR

CH

Practical sourcesAlternative solutions

…

A Hype Cycle of Nonlinear Optics

TIMETrigger

Peak of Hype

Depths of Despair

Hard Work, Realism

Low loss waveguides, new materialsNonlinear Solutions to every problem

Limited real world useNonlinearity

RE

SE

AR

CH

Practical sourcesAlternative solutions

New Trigger

New waveguides enable other possibilities

Nonlinear effects now observed using a wider range of sources

Match wavelengths of source & waveguide zero dispersion

The mid 1990’s saw the development of micro (then nano) structured waveguides with the ability to engineer nonlinearity and 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

• 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

1991

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

Linear dispersion SPM, FWM, RamanSelf-steepening

Three main processes

Soliton ejection

Raman – shift to long l Radiation – shift to short l

Physics: NLSE + perturbations

We use a generalized nonlinear Schrödinger equation (NLSE)

Modelling agrees with experiment !!

Linear dispersion SPM, FWM, RamanSelf-steepening

Three main processes

Soliton ejection

Raman – shift to long l Radiation – shift to short l

Physics: NLSE + perturbations

We use a generalized nonlinear Schrödinger equation (NLSE)

Experiment

Simulation

Wavelength (nm)

Spe

ctru

m (

20 d

B/d

iv)

Output Spectra

Basic description of ultrashort pulses

Ultrafast nonlinear fiber optics

An octave-spanning spectrum allows comb position to be readily stabilized

We can bridge the gap between a knownoptical frequency locked to definition of the second and any optical frequency

Frequency combs find very wide use

Who would have predicted this ?

Example: planetary discovery

Periodic Doppler shift of stellar spectral lines is perturbed by planetary motion

Astrocombs measure radial velocity changes of ~ 10 cm/s

Example: broadband light source

Molecular fingerprinting S. Diddams et al. Nature 445, 627 (2007)  Human breath analysis M. J. Thorpe et al. Opt. Express 16, 2387 (2008) 

Supercontinuum applied in Terabit/s telecommunications

D. Hillerkuss et al.

Here, the nonlinear optics is enabling but the real breakthrough is the system

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

The ability to pressure-tune dispersion in hollow core fibres enables gas-phase nonlinear optics

Nonlinear optics in gas-filled fibres enables UV

Hollow-core photonic crystal fibres for gas-based nonlinear optics, Nat Photon 8, 278–286 (2014)

Exploiting and managing nonlinearity is critical in the design of a wide range of femtosecond sources in many different application regimes

Nonlinear optics is central to fs source development

W Sibbett et al. The development and application of femtosecond laser systemsOptics Express Focus Issue on Modular Ultrafast Lasers 20 6989-7001 (2012)

Nonlinear saturable absorption is a key component of pulsed lasers

Nonlinear optics is central to fs source development

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 are extreme events appearing seemingly from nowhere

• Ocean Waves

1974

1995

Kherif et al. Rogue Waves in the Ocean, Springer (2009)

Rogue waves – rare and extreme surface waves

• Optics

Dudley et al. Nature Photonics 8, 755-764 (2014)

Rogue Waves in a Water Tank Chabchoub et al. Phys. Rev. Lett. 106 204502 (2011)

Now influencing research in fluid mechanics

• Towards truly nanoscale nonlinear optics

Gatass, R. and Mazur, E. Nature Photonics 2,219 (2008)

Nonlinear optics of permanent material modification

Tradeoff between interaction length and intensity

Gaussian beams cannot penetrate deeply in materials

Gaussian beams have an unavoidabletradeoff between interaction lengthand focal spotsize and power density

White,Y. et al, Opt. Express 16,14411 (2008)

Femtosecond ablation for machiningextended channels is a difficult technology

Enhanced interaction lengths also possible in free space

The spatial phase of femtosecond Gaussian beams can be tailored toyield important classes of non-diffracting and accelerating beams

Non-diffracting Bessel Beams

Accelerating Airy Beams M. V. Berry and N. L. BalazsAm. J. Phys. 47 264 (1979)

G. A. Siviloglou et al. Phys. Rev. Lett. 99 213901 (2007)

J. Durnin et al. Phys. Rev. Lett. 58 1499 (1987)

New possibilities for micro and nano structuring

High aspect ratio channels using Bessel beams

Advanced surface machining using accelerating and vortex beams

Expt10 mm

High aspect ratio nanochannels M. Bhuyan et al. Appl. Phys. Lett. 97 081102 (2010)Sending fs pulses in circles F. Courvoiser et al. Opt. Lett. (April 2012)Machining diamond and silicon A. Mathis et al. Appl. Phys. Lett. 101, 071110 (2012)Vortex Bessel beams in graphene B. Wetzel et al. Appl. Phys. Lett. 103, 241111 (2013)

Graphene

New materials enable progress to nanoscale

Theoretical challenges

1. Input pulse is a high-order soliton

2. Perturbation due to proximity to ZDW

3. Break up into fundamental solitons

4. Soliton dynamics - Raman self-frequency shift (RED)

5. Soliton dynamics - Dispersive wave generation (BLUE)

Linear dispersion SPM, FWM, Raman

Major Minor

Characterisation challenge

Time resolved near-field microscopy needs to become an easy technology!

Metamaterials, plasmonics

Enhanced SHGNonlinear phase modulation Fano resonancesBistability

Metamaterial NLSEAllan Boardman Opt. Commun. 283 1585 (2010)

SolitonsParametric amplificationRaman scattering Phase conjugationWavelength conversion

Where are we today with nonlinear nanophotonics?

TIMETrigger

Peak of Hype

Depths of Despair

Hard Work, Realism

Low loss waveguides, new materialsNonlinear Solutions to every problem

Limited real world useNonlinearity

RE

SE

AR

CH

Practical sourcesAlternative solutions

…