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Manipulate light
Space Time
Why?
Because I can
Something cool
Something functional
A bit of both
A 2D Spatial Light Modulator for spatio-temporal shaping
Daan Sprünken
Holoeye HEO1080pPhase-only Spatial Light Modulator
15.4 mm
8.9 mm
Amplitude modulation
Phase modulation
Amplitude
Frequency
Phase
Interference
Interference
Image Phase mask
Laser
Something cool
Something functional
A bit of both
Space Time
Characterisation
Maximum phase delay
Space Time
Something cool
Something functional
A bit of both
Time
How?
Femtosecond laser
30 femtoseconds
0.000000000000030 seconds
3 seconds
Short in time
=
Broad in spectrum
Setup
Diffraction grating
Folding mirror
Focussing mirror
Spatial Light Modulator
Focussing mirror
Diffraction grating
How to get the shortest possible pulse?
Second Harmonic Generation
BB
O
Two photons combined into one
Highest intensity
=
Shortest pulse
Learning loop
Evolutionary algorithm
7 43 42 5 6 8 9
4 70 1 23 6 7 8
59 016345 9
Mike
Janice
Thomas
Mike
Janice
Thomas
9
3
12
45 38 36 32 27
23 21 …
7 41 42 5 0 5 9
4 70 1 23 6 7 8
Mike
Janice
4 50 4 21 0 7 8
7 52 4 21 6 7 8
4 70 1 93 6 4 5
7
8
1
2
Mike
0 43 39 5 2 9 6
Free parameterisation
2p
0
2p
0
Moving nodes parameterisation
2p
0
Moving nodes parameterisation
2p
0
Mike
0 43 39 5 2 9 6
≤ 30%
Learning loop
Phase maskP
has
e
2p
0
p
0 1920
Pixels
Characterise pulses
How do you measure the shortest event?
Measure with itself
FrequencyResolvedOpticalGating
4.5 femtosecond pulseW
avel
en
gth
(n
m) 300
500
400
-40 40
Time (fs)-20 200
Baltuska et al.
FROG setup
FROG setup
FROG setup
FROG setup
in situ FROG
Shaped pulse
Reference pulse
Original pulseW
avel
en
gth
(n
m) 420
380
400
-1000 1000
Time (fs)0
Optimised pulseW
avel
en
gth
(n
m) 420
380
400
-1000 1000
Time (fs)0
Pulse trainW
avel
en
gth
(n
m) 408
392
400
-1000 1000
Time (fs)0
Pulse trainW
avel
en
gth
(n
m) 408
392
400
-1000 1000
Time (fs)0
Something cool
Something functional
A bit of both
Why?
Chemical selectivity
Steer reactions
Activate photosensitive drugs
Spatial distortions
Something cool
Something functional
A bit of both
Time
Freq
uen
cy
Something cool
Something functional
A bit of both
0
1
2
3
0 50 100 150 200 250
Ph
ase
de
lay
(p)
SLM input
Input vs. phase delay
Default
Improved
Cylindrical mirror Diffraction grating Folding mirror Spatial light modulator
Covariance Matrix Adaptation
0
0.5
1
1.5
2
0 50 100 150 200 250
Fitn
ess
Generation
Fitness per generation
Max
Mean
Min
0.7
0.8
0.9
1
0 100 200Op
tim
isat
ion
fact
or
Dimension
0.7
0.8
0.9
1
0 10 20Op
tim
isat
ion
fact
or
Number of offspring m
0.5
0.75
1
0 40 80Op
tim
isat
ion
fact
or
Population size l
0.5
0.75
1
0 0.1 0.2Op
tim
isat
ion
fact
or
Initial scaling factor
Moving nodesFree optimisation
