Single-shot visualization of EVOLVING,
light-speed index structures by multiobject phase contrast imaging
Zhengyan Li, Rafal Zgadzaj, Xiaoming Wang, Chih-Hao Pai, Yen-Yu Chang, Michael C. Downer
Department of Physics, University of Texas at Austin, Austin, TX 78712
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Snapshots of Quasi-static Wakes
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N. H. Matlis et al., Nature Phys. 2, 749 (2006)
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aim of
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0.4 ps
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Movies of Evolving Wakes Captured in a Single Shot...
∆probe(r,)
120 µm
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800 nm, compressed 30 fs(?),
< 1 mJ probe pulse, w0 < 1cm
The vacuum environment
L1 = ?
1 deg.
angle
M1
L0 = ?
35 cm interaction region?
OP1
OP2
OP3
M2
OP4
Optical
quality
window?
What we want to do with index structure n(ζ,x,z)…
1.
2.
3.
4.
Multi-Object-Plane imaging, each object plane (OP) are
imaged to different CCD.
Phase shift imprinted on probe at arbitrary z, not limited to
OPs, is reconstructed.
In single shot, z-depending transverse profile at specific ζ is
obtained.
With multi-shots, full visualization of index object n(ζ,x,z).
Questions:
1.
2.
CCD1
CCD2
CCD4
CCD3
3.
Is the interaction length 35 cm, or longer?
Where is possible for us to couple laser into the chamber?
What are the lengths of L0 and L1? To maintain a good imaging
resolution, we hope L1 is not too large, what is the shortest
length we can get?
Is there anything that potentially blocks or clips the beam
between M1 and M2? Here the angle is 1 deg. = 0.0175 rad, so
the inside diameter of the tube containing the laser has to be
larger than 3 cm, if L0, L1 ~ 50 cm. Is it OK?
Lens f = 75 cm
These are what we expected to observe with 6 cameras
Specs for MOPPCI in FACET
• The minimum angle for oblique angle geometry
θmin = λ/πσ = 0.146 deg
0.72 deg
•
Temporal walk-off
Δt = Lθ2/2c = 38 fs
152 fs
•
@ σ = 100 um
@ σ = 20 um
@ θ = 0.5 deg
@ θ = 1 deg
z-resolution for evolving bubble
δz = σ/θ = 5.73 mm
11.4 mm
2.29 mm
@ σ = 100 um, θ = 1 deg
@ σ = 100 um, θ = 0.5 deg
@ σ = 20 um, θ = 0.5 deg
• ζ-resolution and range for non-evolving bubble
δζ = max{σ(θ/2+φ)/c, tpr} = max{50, 30} = 50 fs
Δζ = Lθ(θ/2+φ)/c = 1.26 ps
@ σ = 100 um, θ = 0.5 deg, φ = 8 deg