Femtosecond Fiber Lasers with Saturable

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Femtosecond Fiber Lasers with Saturable Absobers
Based on Single Wall Carbon Nanotubes V.I.Konov,
E.D.Obraztsova, A.I.Chernov Natural Sciences
Center of General Physics Institute,
Moscow A.V.Tausenev, M.A.Slobodyankin,
P.G.Krjukov, E.M.Dianov Fiber Optics Research
Center, Moscow A.S.Lobach Institute of Problems
of Chemical Physics, Chernogolovka
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Different configurations of single wall carbon
nanotubes
Armchair
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• Two approaches to the problem
• Productive synthesis of single wall carbon
  nanotubes (SWNT) by the chosen technique (in our
  case dc are discharge). Subsequent purification
  of the produced SWNT containing material from
  soot and catalyst particles. Disintegration of
  nanotube bundles. Selection of SWNT by certain
  properties, e.g. type of conductivity. Use of
  SWNT as a dopant in liquids, various bulk
  materials and thin films.
• Synthesis of SWNT directly on substrates by gas
  phase pyrolisis.

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Arc discharge synthesis
NiY2O3 catalyst
Yield 20 g per week
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Typical Raman spectrum of single-wall carbon
nanotubes (SWNT)
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Raman spectra of arc-produced single-wall carbon
nanotubes
?- breathing Raman mode frequency (cm-1),
d nanotube diameter (nm)
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SWNT purification
After chemical treatment
Initial material
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• Liquid suspensions of
  individual single-wall carbon nanotubes

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Final processing technique formation of
surfactant solutions ultrasound treatment
ultracentrifuge
Ultrasound treatment
Aqueous suspensions of different quality
Ultracentrifuge (gt100.000g)
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• Three types of SWNT containing media
• Liquid suspensions (D2O or H2O)
• Free standing membranes (base materials water
  soluable polymers or cellulose derivatives,
  thickness 5-100µ)
• Coatings

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Absorbtion spectra of SWNT liquid suspension
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Energy levels of semiconductor SWNT
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• Non-linear optical properties
• of single-wall carbon nanotubes

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Non-linear transmission (?1.54 ?m)
of SWNT
suspension in D2O
N.N. Ilichev, E.D. Obraztsova, S.V. Garnov, S.E.
Mosaleva , Quantum Electronics 34 (2004) 572
For different wavelengths the saturation depth
varies from 2.5 to 8
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• Saturable absorbers based on
• single-wall carbon nanotubes
• for laser mode-locking

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2 types of SWNT-based saturable absorbers for
solid-state lasers
SWNT aqueous suspensions
SWNT-containing composites
1,2- spherical mirrors
3 - Er3-doped glass
(l1.54 mm) 4 -
Flash-lamp-pumping module
5 - SWNT saturable absorber
6- avalanche photodiode
7- oscilloscope
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Mode-Locking in Er3-Glass Laser (?1.54 µm)
N.N. Ilichev, E.D. Obraztsova, S.V. Garnov,
S.E. Mosaleva 1.54 mm nonlinear transmission of
single-wall carbon nanotube suspension in
D2O realization of self-mode-locking regime in
Er3-glass laser with nanotube-based Q-switcher,

Quantum Electronics 34 (2004) 572.
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Spectral range of passive Q-switching with SWNT
suspension
The arrows show the wavelength of lasers for
which the regime has been realized experimentally
? Er3 doped glass, ?1.54 ?m ? YAPNd3
and NdGdVO4 crystals, ?1.34 ?m ?
LiF with F2- - CC, ??1.15 ?m ? YAGNd3
crystal, ?1.064 ?m ? Nd3 doped glass,
?1.055 ?m.
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• SWNT films
• as saturable absorbers
• in Fiber Lasers

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UV-NIR-VIS optical absorption spectrum of the
composite film SWNTs carboximetilcellulose
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Laser diode (980 nm)
Er3 - fiber
SWNT module
Mirror (100)
Coupler
Multiplexer
fiber
Mirror (100)
SWNT film
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• Active fiber length 0.9 m
• Pulse repetition rate 28.5 MHz
• Pulse duration 1.17 ps
• Pump power 40 mW
• Output power 4 mW

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Scheme of Er3- fiber laser with a ring
resonator containing a saturable
absorber arc SWNTs polymer
Film with SWNTs
A.V. Tausenev, E.D. Obraztsova, A.S. Lobach et
al., Quantum Electronics 37 (2007) 205-208.
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Connectors in fiber lasers

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177 fs pulses
A.V. Tausenev, E.D. Obraztsova, A.S. Lobach,
A.I. Chernov,V.I. Konov, P.G. Kryukov, A.V.
Konyashchenko and E.M. Dianov, APL 92 (N18)
(2008)171113 .
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Mode-locking of Thulium fiber laser with SWNT
saturable absorber
1.93 ?m
2.05 ps
M.A.Solodyankin, E.D. Obraztsova, A. S. Lobach,
A. I. Chernov, A.V.Tausenev, V.I. Konov and E.M.
Dianov, Optics Letters 33 (2008) 1336.

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Conclusions

• SWNT based optical grade media of 2 types-
  liquid suspensions- polymeric films with
  thickness up to 10 ?mwith concentration of SWNT
  up to 0.01-0.02 have been developed.
• It is shown that the new optical materials are
  efficient and ultrafast light saturable
  absorbers, allowing to - produce ultrashort
  femto and picosecond laser pulses (the smallest
  pulse duration was 177fs)- in a broad range of
  peak and mean laser power (1-2?m)

The work was supported by Russian Foundation for
Basic Research and by RAS program Femtosecond
optics.