Introducing PCF
Introducing PCF
Introducing PCF
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© Philip Russell, MPL, Erlangen<br />
1
© Philip Russell, MPL, Erlangen<br />
1
© Philip Russell, MPL, Erlangen<br />
Topics<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
<strong>Introducing</strong> <strong>PCF</strong><br />
Out of the strait-jacket<br />
Bars, windows & cages<br />
Cutting the losses<br />
Gas-laser interactions<br />
Laser-driven rockets<br />
Brighter than 10,000 suns<br />
Anomalous cornering<br />
Nano-phononics<br />
Nanowires<br />
Impact & prospects<br />
2
© Philip Russell, MPL, Erlangen<br />
photonic<br />
crystal<br />
fibres<br />
3
© Philip Russell, MPL, Erlangen<br />
diameter of a<br />
human hair<br />
The 1991 idea…<br />
…to trap light inside an<br />
hollow tube using the<br />
photonic band gap effect<br />
4
© Philip Russell, MPL, Erlangen<br />
1991<br />
notes made at CLEO/QELS, 13th May 1991<br />
“Photonic Bloch waves,” NATO ASI, Erice, Sicily, July 1993<br />
5
© Philip Russell, MPL, Erlangen<br />
<strong>PCF</strong> citations (January 2009)<br />
first journal<br />
paper (1995)<br />
NB: approximate<br />
6
© Philip Russell, MPL, Erlangen<br />
1 mm capillary<br />
(pure silica)<br />
rare-earth<br />
doped<br />
high<br />
index<br />
defect<br />
Stacking & drawing<br />
birefringent<br />
core<br />
low index<br />
defect<br />
draw<br />
~1 mm<br />
~1800°C<br />
photonic<br />
crystal fibre<br />
~0.03 mm<br />
7
© Philip Russell, MPL, Erlangen<br />
The World’s Longest Holes<br />
Guinness Book of Records 1998<br />
Interplanetary Channel Tunnel<br />
Earth<br />
An Interplanetary<br />
Channel Tunnel…<br />
…would have the same<br />
aspect ratio as a hole 25 nm<br />
in diameter and 1 km long<br />
Jupiter<br />
8
© Philip Russell, MPL, Erlangen<br />
BlazePhotonics Bath<br />
Bath<br />
Bath<br />
Erlangen<br />
10 μm<br />
photonic<br />
crystal<br />
fibres<br />
Erlangen<br />
BlazePhotonics<br />
Erlangen<br />
9
© Philip Russell, MPL, Erlangen<br />
New Age Crystals<br />
The Economist<br />
21 Nov 1998<br />
10
© Philip Russell, MPL, Erlangen<br />
Iridescence in Nature<br />
sea-mouse<br />
cross-section of hair<br />
11<br />
~1 μm
© Philip Russell, MPL, Erlangen<br />
Alfried Krupp<br />
von Bohlen und<br />
Halbach - Stiftung<br />
Topics<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
<strong>Introducing</strong> <strong>PCF</strong><br />
Out of the strait-jacket<br />
Bars, windows & cages<br />
Cutting the losses<br />
Gas-laser interactions<br />
Laser-driven rockets<br />
Brighter than 10,000 suns<br />
Anomalous cornering<br />
Nanophononics<br />
Nanowires<br />
Impact & prospects<br />
12
© Philip Russell, MPL, Erlangen<br />
•<br />
Wavevectors …<br />
β<br />
kn1<br />
axial wavevector β is conserved<br />
across every region of structure<br />
k = 2 π / λ<br />
t1 t1<br />
transverse<br />
effective wavelength<br />
in material 1<br />
13
© Philip Russell, MPL, Erlangen<br />
Hexagonal lattice silica:air<br />
Birks et al, Electron.Lett. 31 (1941-1942) 1995<br />
normalised frequency ωΛ/c<br />
12<br />
11<br />
10<br />
9<br />
8<br />
7<br />
vacuum<br />
full photonic<br />
band gaps<br />
<strong>PCF</strong> cladding<br />
silica<br />
6<br />
6 7 8 9 10 11 12<br />
normalised wavevector along fibre βΛ<br />
propagating<br />
evanescent<br />
propagating<br />
evanescent<br />
propagating<br />
evanescent<br />
•<br />
•<br />
45% air filling<br />
fraction<br />
silica:air index<br />
contrast 1.46:1<br />
β<br />
14
© Philip Russell, MPL, Erlangen<br />
Single-mode fibre strait-jacket<br />
normalised frequency ωΛ/c<br />
12<br />
11<br />
10<br />
9<br />
8<br />
7<br />
Anthony Hopkins<br />
(Hannibal Lecter)<br />
vacuum<br />
silica<br />
propagating<br />
evanescent<br />
Ge-doped silica<br />
6<br />
6 7 8 9 10 11 12<br />
normalised wavevector along fibre βΛ<br />
guided<br />
modes<br />
silica<br />
Ge-silica<br />
15
© Philip Russell, MPL, Erlangen<br />
Birks et al, Electron.Lett. 31 (1941-1942) 1995<br />
normalised frequency ωΛ/c<br />
12<br />
11<br />
10<br />
9<br />
8<br />
7<br />
vacuum<br />
full photonic<br />
band gaps<br />
<strong>PCF</strong> playing field<br />
<strong>PCF</strong> cladding<br />
silica<br />
6<br />
6 7 8 9 10 11 12<br />
normalised wavevector along fibre βΛ<br />
propagating<br />
evanescent<br />
•<br />
•<br />
45% air filling<br />
fraction<br />
silica:air index<br />
contrast 1.46:1<br />
β<br />
16
© Philip Russell, MPL, Erlangen<br />
Alfried Krupp<br />
von Bohlen und<br />
Halbach - Stiftung<br />
Topics<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
<strong>Introducing</strong> <strong>PCF</strong><br />
Out of the strait-jacket<br />
Bars, windows & cages<br />
Cutting the losses<br />
Gas-laser interactions<br />
Laser-driven rockets<br />
Brighter than 10,000 suns<br />
Anomalous cornering<br />
Nanophononics<br />
Nanowires<br />
Impact & prospects<br />
17
© Philip Russell, MPL, Erlangen<br />
Solid core Δn ∞<br />
~100 μm<br />
> 0 (1995)<br />
traps light by modified total<br />
internal reflection (highly<br />
dispersive cladding crystal)<br />
18
© Philip Russell, MPL, Erlangen<br />
Total internal reflection gives…<br />
glass<br />
air<br />
glass<br />
…unconditional evanescence<br />
anti-resonant<br />
tunnelling<br />
19
© Philip Russell, MPL, Erlangen<br />
Endlessly single-mode <strong>PCF</strong><br />
the first photonic crystal fibre...<br />
20<br />
Knight et al, OFC 1996 PD paper<br />
far-field pattern when<br />
carrying green & red light
© Philip Russell, MPL, Erlangen<br />
Higher order modes are filtered away<br />
evanescence<br />
•<br />
fundamental mode<br />
cannot squeeze<br />
between air-holes<br />
anti-resonant<br />
unit cell<br />
•<br />
resonant<br />
unit cell<br />
higher-order modes can<br />
escape into cladding<br />
21
© Philip Russell, MPL, Erlangen<br />
Resonance & anti-resonance<br />
in nano-tube<br />
anti-resonant<br />
glass<br />
air<br />
glass<br />
resonant<br />
anti-resonant<br />
light fills the tube only at specific angle/colour combinations<br />
22
© Philip Russell, MPL, Erlangen<br />
B<br />
A<br />
Unit cells & evanescence<br />
unit cell boundary<br />
[M] = transfer matrix<br />
•<br />
Bloch wave transfer<br />
matrix [M]:<br />
•<br />
•<br />
1<br />
λλ<br />
real eigenvalues:<br />
evanescence<br />
∗ =<br />
λλ<br />
=<br />
ee<br />
∗ γ −γ<br />
complex eigenvalues:<br />
propagation<br />
λλ<br />
=<br />
e e<br />
∗ iγ−iγ 23
© Philip Russell, MPL, Erlangen<br />
Building a prison for light<br />
the prison<br />
cell<br />
bars of the prison cell<br />
24
© Philip Russell, MPL, Erlangen<br />
We are keeping light<br />
anti-resonant<br />
windows<br />
“behind bars”<br />
anti-resonant<br />
bars<br />
25
© Philip Russell, MPL, Erlangen<br />
~100 μm<br />
The hollow one…<br />
traps light by creating a<br />
complete 2D photonic<br />
band gap in the cladding<br />
26
© Philip Russell, MPL, Erlangen<br />
Alfried Krupp<br />
von Bohlen und<br />
Halbach - Stiftung<br />
Topics<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
<strong>Introducing</strong> <strong>PCF</strong><br />
Out of the strait-jacket<br />
Bars, windows & cages<br />
Cutting the losses<br />
Gas-laser interactions<br />
Laser-driven rockets<br />
Brighter than 10,000 suns<br />
Anomalous cornering<br />
Nanophononics<br />
Nanowires<br />
Impact & prospects<br />
27
© Philip Russell, MPL, Erlangen<br />
State-of-the-art hollow-core <strong>PCF</strong> (2004)<br />
70 μm<br />
115 μm<br />
28<br />
Roberts et al, Opt. Exp. 13 (236-244) 2005<br />
20.5 μm<br />
1 dB/km at 1550 nm
© Philip Russell, MPL, Erlangen<br />
Guidance in hollow core (PBG) fibre<br />
refraction<br />
refraction<br />
photonic<br />
bandgap<br />
air<br />
air<br />
air<br />
light can be guided in<br />
hollow core fibres<br />
using a photonic<br />
bandgap<br />
cross-section of<br />
photonic bandgap<br />
fibre<br />
29
© Philip Russell, MPL, Erlangen<br />
At 1 dB/km: How good are the mirrors?<br />
2.8 million bounces per km (20 μm core, 1550 nm)<br />
0.35 μdB/bounce (reflectivity 0.99999992)<br />
2.8 million cylindrical mirrors<br />
cladding<br />
core<br />
30
© Philip Russell, MPL, Erlangen<br />
Typical attenuation spectrum<br />
Roberts et al, Opt. Exp. 13 (236-244) 2005<br />
Attenuation [dB/km]<br />
30<br />
25<br />
20<br />
15<br />
10<br />
5<br />
0<br />
1500 1520 1540 1560 1580 1600 1620 1640<br />
Wavelength [nm]<br />
~1.7 dB/km<br />
31
© Philip Russell, MPL, Erlangen<br />
Loss is induced by surface states<br />
effective mode index<br />
blaze photonics<br />
1.001<br />
1.000<br />
0.999<br />
0.998<br />
0.997<br />
0.996<br />
0.995<br />
light line<br />
32<br />
Roberts et al, Opt. Exp. 13 (236-244) 2005<br />
1690 nm 1530 nm 1400 nm<br />
“surface modes”<br />
0.994<br />
14.0 14.5 15.0 15.5 16.0 16.5 17.0 17.5 18.0<br />
normalised propagation constant [ βΛ<br />
fundamental mode<br />
]
© Philip Russell, MPL, Erlangen<br />
Mode profiles at anti-crossing<br />
fraction of light in glass changes dramatically<br />
with wavelength of the light<br />
33
© Philip Russell, MPL, Erlangen<br />
dB/m<br />
Eliminate surface states…<br />
0.02 dB/m<br />
wavelength<br />
Erlangen result<br />
34<br />
Bath/Southampton, OpEx Jan 2008
© Philip Russell, MPL, Erlangen<br />
Alfried Krupp<br />
von Bohlen und<br />
Halbach - Stiftung<br />
Topics<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
<strong>Introducing</strong> <strong>PCF</strong><br />
Out of the strait-jacket<br />
Bars, windows & cages<br />
Cutting the losses<br />
Gas-laser interactions<br />
Laser-driven rockets<br />
Brighter than 10,000 suns<br />
Anomalous cornering<br />
Nanophononics<br />
Nanowires<br />
Impact & prospects<br />
35
© Philip Russell, MPL, Erlangen<br />
Enhancing nonlinear effects in gases<br />
Need to optimise:<br />
nonlinearity<br />
provided by<br />
gas in hollow core<br />
low loss<br />
required<br />
x path-length<br />
x power/area<br />
small as possible<br />
(single-mode preferred)<br />
36
© Philip Russell, MPL, Erlangen<br />
Depth of focus & spot size<br />
Lord Rayleigh<br />
1842-1919<br />
intensity<br />
∝<br />
1/<br />
a<br />
interaction length<br />
2<br />
Rayleigh length<br />
∝<br />
2<br />
a / λ<br />
37<br />
spot size
© Philip Russell, MPL, Erlangen<br />
Hollow core <strong>PCF</strong>: ~infinite Rayleigh length<br />
holey cladding<br />
holey cladding<br />
intensity<br />
∝<br />
1/<br />
a<br />
absorption length<br />
for gas-laser interactions the<br />
best low loss <strong>PCF</strong> is seven<br />
orders of magnitude better<br />
than a focused beam<br />
2<br />
∝ 1/ α<br />
38<br />
infinite depth of focus
© Philip Russell, MPL, Erlangen<br />
Molecular oscillations in H 2<br />
Q01(1) S00(1) vibrational<br />
(usually dominant)<br />
rotational<br />
(usually much weaker)<br />
125 THz 18 THz<br />
39<br />
Benabid et al, PRL 93 (123903) 2004
© Philip Russell, MPL, Erlangen<br />
Hollow core <strong>PCF</strong> for rotational SRS<br />
18 THz<br />
rotational<br />
anti-Stokes pump<br />
Stokes<br />
40<br />
Benabid et al, PRL 93 (123903) 2004<br />
very high attenuation<br />
for vibrational Stokes<br />
125 THz
© Philip Russell, MPL, Erlangen<br />
transmission<br />
0.5<br />
0.4<br />
0.3<br />
0.2<br />
0.1<br />
0.0<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
0.0<br />
0 5 10 15 20 25 30<br />
coupled energy (nJ)<br />
SRS conversion<br />
35 m<br />
0 20 40 60 80<br />
coupled energy (nJ)<br />
2.9 m<br />
hydrogen pressure 7 bar<br />
loss at second Stokes is 0.6 dB/m<br />
•<br />
•<br />
single-pass threshold<br />
at energy 1,000,000<br />
times lower (35 m)<br />
near-perfect quantum<br />
efficiency achieved (2.9<br />
m)<br />
multi-pass: Meng et al.,<br />
Opt. Lett. 27 (1226) 2002<br />
41<br />
Benabid et al, PRL 93 (123903) 2004
© Philip Russell, MPL, Erlangen<br />
Alfried Krupp<br />
von Bohlen und<br />
Halbach - Stiftung<br />
Topics<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
<strong>Introducing</strong> <strong>PCF</strong><br />
Out of the strait-jacket<br />
Bars, windows & cages<br />
Cutting the losses<br />
Gas-laser interactions<br />
Laser-driven rockets<br />
Brighter than 10,000 suns<br />
Anomalous cornering<br />
Nanophononics<br />
Nanowires<br />
Impact & prospects<br />
42
© Philip Russell, MPL, Erlangen<br />
laser<br />
beam<br />
gravity<br />
propulsive<br />
force<br />
trapping<br />
forces<br />
Laser tweezer<br />
forces<br />
Arthur Ashkin<br />
(1922-)<br />
43
© Philip Russell, MPL, Erlangen<br />
non-diffracting<br />
laser beam<br />
gravity<br />
constant<br />
propulsive<br />
force<br />
trapping<br />
forces<br />
Laser tweezer<br />
forces<br />
44
© Philip Russell, MPL, University Erlangen of Bath<br />
•<br />
•<br />
•<br />
•<br />
Piped particle<br />
20 μm diameter hollow core<br />
5 μm diameter polystyrene spheres<br />
80 mW at 514 nm<br />
terminal velocity 1.5 cm/sec<br />
45<br />
Benabid et al, Opt. Exp. 10 (1195-1203) 2002
© Philip Russell, MPL, Erlangen<br />
Laser-driven rocket motors<br />
laser light<br />
scattering<br />
acceleration<br />
V = 3 LPn/( r ρ r c)<br />
2<br />
p p c<br />
particle diameter 100 nm,<br />
density 1000 kg/m 3<br />
evacuated hollow core,<br />
10 μm in diameter<br />
1 W laser power<br />
28 km/s (0.7 pJ) after 100 m<br />
46
© Philip Russell, MPL, Erlangen<br />
activating<br />
laser<br />
light<br />
Laser tweezers in hollow core <strong>PCF</strong><br />
hollow core filled<br />
with biochemicals<br />
in aqueous solution<br />
holey<br />
cladding<br />
cell<br />
highly controlled<br />
micro-environment<br />
laser<br />
liquid-filled<br />
hollow core<br />
microfluidic<br />
counter-flow<br />
possible<br />
holey<br />
cladding<br />
47<br />
effectiveness of photochemicals<br />
for killing cancer<br />
cells can be explored
© Philip Russell, MPL, Erlangen<br />
Alfried Krupp<br />
von Bohlen und<br />
Halbach - Stiftung<br />
Topics<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
<strong>Introducing</strong> <strong>PCF</strong><br />
Out of the strait-jacket<br />
Bars, windows & cages<br />
Cutting the losses<br />
Gas-laser interactions<br />
Laser-driven rockets<br />
Brighter than 10,000 suns<br />
Anomalous cornering<br />
Nanophononics<br />
Nanowires<br />
Impact & prospects<br />
48
© Philip Russell, MPL, Erlangen<br />
Supercontinuum<br />
generation<br />
photonics & new materials<br />
Dudley et al, Rev. Mod.<br />
Phys. 78,1135 (2006)<br />
49
© Philip Russell, MPL, Erlangen<br />
Pulse bandwidth & duration<br />
100 wave pulse<br />
time<br />
1000 wave pulse<br />
bandwidth × duration = constant<br />
50
© Philip Russell, MPL, Erlangen<br />
geomagnetic<br />
equator<br />
11°<br />
geomagnetic<br />
axis<br />
Whistlers & dispersion<br />
axis of<br />
rotation<br />
whistler waves<br />
radiation belt<br />
electrons<br />
plasma-sphere<br />
geomagnetic<br />
field lines<br />
51
© Philip Russell, MPL, Erlangen<br />
GVD (ps/nm.km)<br />
300<br />
200<br />
100<br />
0<br />
–100<br />
–200<br />
Dispersion of 800 nm core <strong>PCF</strong><br />
800 nm<br />
<strong>PCF</strong> (measured)<br />
bulk silica<br />
anomalous<br />
normal<br />
–300<br />
0.5 0.6 0.7 0.8 0.9 1.0<br />
zero dispersion can be designed<br />
wavelength (μm)<br />
to lie anywhere in this range<br />
zero chromatic<br />
dispersion (560 nm)<br />
52<br />
Knight et al, Phot Tech Lett, 12 (807-809) 2000<br />
zero at<br />
~1300 nm
© Philip Russell, MPL, Erlangen<br />
Recipe for Supercontinuum:<br />
take solid-core <strong>PCF</strong> with zero<br />
chromatic dispersion wavelength<br />
close to a pulsed laser wavelength<br />
zero chromatic dispersion keeps the<br />
energy packet together and<br />
enhances nonlinear effects<br />
53
© Philip Russell, MPL, Erlangen<br />
Ti:sapphire laser pump (200 fs)<br />
visible spectrum<br />
<strong>PCF</strong><br />
diffraction<br />
grating<br />
higher grating<br />
orders<br />
IR in (76 MHz<br />
200 fsec, 2<br />
nJ)<br />
54<br />
Ranka et al, Opt. Lett. 25 (25-27) 2000<br />
… some 10,000× brighter than the sun,<br />
yielding more than 100 GW m –2sterad –1
© Philip Russell, MPL, Erlangen<br />
•<br />
•<br />
•<br />
optical coherence<br />
tomography<br />
optical spectroscopy<br />
frequency metrology<br />
fs<br />
frequency<br />
comb<br />
Applications<br />
Nobel Prize 2005<br />
John Hall Roy Glauber Ted Hänsch<br />
55
© Philip Russell, MPL, Erlangen<br />
Short pulse laser (10 -13<br />
mirror<br />
mode-locker<br />
amplifying<br />
medium<br />
standing waves of<br />
different frequencies<br />
semi-transparent<br />
mirror<br />
sec)<br />
10 -13<br />
train of femtosecond<br />
sec<br />
pulses<br />
56
© Philip Russell, MPL, Erlangen<br />
E(t)<br />
E(f)<br />
f 0<br />
T<br />
frequency offset<br />
f0 = Δt / T2 Δt 2Δt<br />
laser repetition rate<br />
Fourier transform<br />
frequency<br />
comb<br />
frequency<br />
57<br />
time
© Philip Russell, MPL, Erlangen<br />
precise positioning of the<br />
zero is essential<br />
Using a ruler<br />
then precise distance<br />
can be read off<br />
58
© Philip Russell, MPL, Erlangen<br />
intensity<br />
Measuring with frequency comb<br />
nfR+f0 <strong>PCF</strong> supercontinuum<br />
×2<br />
2(nfR+f0) 2nfR+f0 beat, f 0<br />
59
© Philip Russell, MPL, Erlangen<br />
Nobel Prize for Physics 2005<br />
Roy Glauber, John Hall & Ted Hänsch:<br />
“It is possible to create pulses of this kind with a<br />
sufficiently broad frequency range in so-called photonic<br />
crystal fibres, in which the material is partially<br />
replaced by air filled channels. In these fibres a<br />
broad spectrum of frequencies can be generated by the<br />
light itself. Hänsch and Hall and their colleagues have<br />
subsequently, partly in collaborative work, refined these<br />
techniques into a simple instrument that has already<br />
gained wide use and is commercially available. ”<br />
60
© Philip Russell, MPL, Erlangen<br />
Hand-held SC source with microchip laser<br />
wavelength (μm)<br />
1.6<br />
1.4<br />
1.2<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
30 mW<br />
61<br />
Wadsworth et al, Opt Exp 12 (299-309) 2004<br />
average at 7.25 kHz (0.6 ns, 1064 nm)<br />
= pulse energy 4.1 μJ & peak power 6.9 kW<br />
20 m<br />
0 5 10 15 20 25 30<br />
pump power (mW)<br />
flat to<br />
within<br />
factor<br />
of 2×<br />
<strong>PCF</strong> with ZDW at 1039 nm<br />
6 μm<br />
anomalous dispersion
© Philip Russell, MPL, Erlangen<br />
Supercontinuum source (Fianium<br />
Nd:fibre laser & amplifier (1064 nm, 5 ps, 10-11 W launched)<br />
Repetition rate - 50 MHz, total SC power 6.5 W<br />
4.5 mW/nm 450-800 nm<br />
Ltd)<br />
62
© Philip Russell, MPL, Erlangen<br />
spectral density (dBm/nm)<br />
10.0<br />
0.0<br />
-10.0<br />
-20.0<br />
-30.0<br />
-40.0<br />
-50.0<br />
-60.0<br />
Broad-band light sources<br />
<strong>PCF</strong> SC source<br />
(ps fiber laser)<br />
<strong>PCF</strong> SC source<br />
(ns microchip laser)<br />
SLEDs (4 wavelengths)<br />
incandescent lamp<br />
400 600 800 1000 1200 1400 1600<br />
wavelength (nm)<br />
fiber ASE<br />
source<br />
1 mW/nm<br />
1 µW/nm<br />
1 nW/nm<br />
63
© Philip Russell, MPL, Erlangen<br />
Alfried Krupp<br />
von Bohlen und<br />
Halbach - Stiftung<br />
Topics<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
<strong>Introducing</strong> <strong>PCF</strong><br />
Out of the strait-jacket<br />
Bars, windows & cages<br />
Cutting the losses<br />
Gas-laser interactions<br />
Laser-driven rockets<br />
Brighter than 10,000 suns<br />
Anomalous cornering<br />
Nanophononics<br />
Nanowires<br />
Impact & prospects<br />
64
© Philip Russell, MPL, Erlangen<br />
Photonic band gaps at 1% contrast<br />
“bars” resonant in<br />
pass-bands<br />
pure silica<br />
glass matrix<br />
core<br />
anti-resonant<br />
unit cell<br />
Ge-doped silica<br />
(~1% above silica)<br />
65<br />
Argyros et al., Opt. Exp. 13 (309-314) 2005<br />
Bouwmans et al., Opt. Exp.<br />
13 (8452) 2005 (< 20 dB/km)
© Philip Russell, MPL, Erlangen<br />
Mode patterns in cladding “rods”<br />
transmission (dB)<br />
0<br />
-10<br />
-20<br />
LP 21 LP 02 LP 11<br />
LP 10<br />
-30<br />
450 650 850 1050 1250 1450<br />
wavelength (nm)<br />
66<br />
Argyros et al., Opt. Exp. 13 (309-314) 2005<br />
cladding rods<br />
become resonant in<br />
the visible<br />
NB: these are not<br />
bound waveguide<br />
modes
© Philip Russell, MPL, Erlangen<br />
Bend loss: step index fibre<br />
refractive index<br />
leakage<br />
left<br />
core<br />
straight<br />
core<br />
RH bend<br />
guided<br />
mode<br />
67
© Philip Russell, MPL, Erlangen<br />
refractive index<br />
Band gap guidance<br />
guided mode<br />
T. A. Birks et al.,<br />
"Bend loss in all-solid bandgap fibres,"<br />
Opt. Exp. 14, 5688-5698 (2006)<br />
straight<br />
upper band edge<br />
photonic band gap<br />
lower band edge<br />
68
© Philip Russell, MPL, Erlangen<br />
Anomalous<br />
cornering<br />
index<br />
mode 1<br />
mode 2<br />
leakage left<br />
RH bend<br />
leakage right<br />
upper band edge<br />
photonic band gap<br />
lower band edge<br />
69
© Philip Russell, MPL, Erlangen<br />
Alfried Krupp<br />
von Bohlen und<br />
Halbach - Stiftung<br />
Topics<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
<strong>Introducing</strong> <strong>PCF</strong><br />
Out of the strait-jacket<br />
Bars, windows & cages<br />
Cutting the losses<br />
Gas-laser interactions<br />
Laser-driven rockets<br />
Brighter than 10,000 suns<br />
Anomalous cornering<br />
Nanophononics<br />
Nanowires<br />
Impact & prospects<br />
70
© Philip Russell, MPL, Erlangen<br />
ωopt<br />
frequency<br />
light<br />
optical<br />
SBS<br />
acoustic<br />
Phonon dispersion<br />
0 wavevector<br />
π/a<br />
a<br />
71
© Philip Russell, MPL, Erlangen<br />
anti-Stokes<br />
Brillouin scattering<br />
frequency<br />
Stokes frequency<br />
light<br />
(slope c/ n )<br />
shift changes<br />
with pump<br />
frequency<br />
0<br />
axial wavevector<br />
pump<br />
72<br />
Dainese et al., Opt. Exp. 14, 4141, 2006<br />
very large<br />
phonon<br />
momentum<br />
needed
© Philip Russell, MPL, Erlangen<br />
ωopt<br />
frequency<br />
light<br />
optical<br />
SBS<br />
SRS<br />
acoustic<br />
Phonon dispersion<br />
0 wavevector<br />
π/a<br />
a<br />
73
© Philip Russell, MPL, Erlangen<br />
Acoustic modes in silica strand<br />
frequency<br />
flat bands<br />
Gustavo Wiederhecker<br />
axial wavevector<br />
74
© Philip Russell, MPL, Erlangen<br />
cut-off<br />
frequency<br />
frequency<br />
ω AC<br />
Raman-like scattering<br />
optical<br />
dispersion<br />
ω S2<br />
ω S1<br />
ω AS1<br />
wavevector<br />
ω AS2<br />
ωP multiple scattering<br />
orders possible<br />
acoustic<br />
dispersion<br />
scattering is<br />
Raman-like<br />
frequency shift<br />
independent of<br />
laser fequency<br />
75
© Philip Russell, MPL, Erlangen<br />
•<br />
Polarimetric<br />
• launch equal amounts of<br />
light into both<br />
polarisation states of<br />
birefringent fibre<br />
• use analyser at output to<br />
monitor relative pathlength<br />
changes<br />
• useful for observing<br />
modes that cause<br />
elliptical core distortion<br />
Diagnostic techniques<br />
•<br />
pulsed light<br />
source<br />
Sagnac<br />
• place <strong>PCF</strong> sample<br />
asymmetrically in long<br />
Sagnac loop mirror<br />
• launch 100 ps pump pulses<br />
• observe transmitted signal<br />
pulse<br />
generator<br />
76
© Philip Russell, MPL, Erlangen<br />
Photoacoustic<br />
100 ps pulses launched with CW<br />
probe at a different wavelength<br />
measurements<br />
77<br />
Dainese et al., Opt. Exp. 14, 4141, 2006
© Philip Russell, MPL, Erlangen<br />
Coherent control of phonon resonances<br />
cancellation<br />
reinforcement<br />
1 μm<br />
laser pulses<br />
acoustic<br />
oscillation<br />
time<br />
78<br />
Wiederhecker, PRL 100, 203903 (2008)
© Philip Russell, MPL, Erlangen<br />
Coherent control of waveform<br />
amplitude<br />
0<br />
27 pulses<br />
1 pulse<br />
0 10 20 30 40<br />
time (ns)<br />
•<br />
•<br />
response is more<br />
single-frequency<br />
with 27 pulses<br />
favours a single<br />
resonant mode<br />
79
© Philip Russell, MPL, Erlangen<br />
Growth with number of pulses<br />
two different <strong>PCF</strong>s<br />
theory (including<br />
acoustic lifetime)<br />
80<br />
PRL 100, 203903 (2008)<br />
experiment + theory<br />
(including acoustic<br />
lifetime & EDFA<br />
saturation)
© Philip Russell, MPL, Erlangen<br />
Alfried Krupp<br />
von Bohlen und<br />
Halbach - Stiftung<br />
Topics<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
<strong>Introducing</strong> <strong>PCF</strong><br />
Out of the strait-jacket<br />
Bars, windows & cages<br />
Cutting the losses<br />
Gas-laser interactions<br />
Laser-driven rockets<br />
Brighter than 10,000 suns<br />
Anomalous cornering<br />
Nanophononics<br />
Nanowires<br />
Impact & prospects<br />
81
© Philip Russell, MPL, Erlangen<br />
Gold wire in birefringent <strong>PCF</strong><br />
900 nm wire 600 nm wire<br />
82<br />
Lee et al., APL 93, 111102 (2008)
© Philip Russell, MPL, Erlangen<br />
Spiralling plasmon mode<br />
ε ε ⎛( m −1)<br />
⎞<br />
nm= − , m≥1<br />
ε ε<br />
dielectric metal<br />
mode order<br />
D M<br />
⎜ ⎟<br />
D + M ⎝ ka 0 ⎠<br />
2<br />
Schmidt et al., Opt. Exp. 16 13617 (2008)<br />
metal wire<br />
radius a<br />
83
© Philip Russell, MPL, Erlangen<br />
Experimental set-up<br />
84<br />
Lee et al., APL 93, 111102 (2008)
© Philip Russell, MPL, Erlangen<br />
Transmission spectra<br />
6 mm<br />
25 mm<br />
85<br />
Lee et al., APL 93, 111102 (2008)
© Philip Russell, MPL, Erlangen<br />
Ge<br />
nanowires<br />
600 nm wires 1700 nm wire<br />
conductivity 49 Ω.m<br />
(crystalline Ge 47 Ω.m)<br />
86<br />
Tyagi et al., Opt Exp, 16 17227 (2008)
© Philip Russell, MPL, Erlangen<br />
Micro-Raman signal<br />
μ-Raman<br />
spectrometer<br />
crystalline Ge: 300 cm-1 linewidth 2.4 cm-1 87<br />
Tyagi et al., Opt Exp, 16 17227 (2008)
© Philip Russell, MPL, Erlangen<br />
Alfried Krupp<br />
von Bohlen und<br />
Halbach - Stiftung<br />
Topics<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
<strong>Introducing</strong> <strong>PCF</strong><br />
Out of the strait-jacket<br />
Bars, windows & cages<br />
Cutting the losses<br />
Gas-laser interactions<br />
Laser-driven rockets<br />
Brighter than 10,000 suns<br />
Anomalous cornering<br />
Nanophononics<br />
Nanowires<br />
Impact & prospects<br />
88
© Philip Russell, MPL, Erlangen<br />
transforming fibre optics<br />
intra-fibre devices<br />
biomedical/chemical sensors<br />
Impact & prospects<br />
cold atom guiding<br />
laser guidance of particles/cells<br />
single mode fibre gas cells<br />
dispersion control<br />
nanophononic devices<br />
new regimes for nonlinear optics<br />
broad-band white light<br />
frequency comb measurement<br />
non-silica glass & polymer fibres<br />
metal & semiconductor nanowires<br />
fibre lasers & amplifiers<br />
high power & energy transmission<br />
89
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