Single-shot visualization of EVOLVING, light-speed index structures by multi-

object phase contrast imagingZhengyan 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

1

120 µm0.4 ps

∆probe(r,)

N. H. Matlis et al., Nature Phys. 2, 749 (2006)

Snapshots of Quasi-static Wakes

aim of this work

micron

micron

0 5 10 15 20

0

5

10

15

20

25

30

micron

micron

20 40 60 80 100 120 140 160 180

20

40

60

80

100

120

140

160

micron

micron

0 2 4 6 8 10 12 14 16

0

5

10

15

20

25

30

0 2 4 6 8 10 12 14 16

0

5

10

15

20

25

30

0 5 10 15

0

5

10

15

20

25

30

0 2 4 6 8 10 12 14 16 18

0

5

10

15

20

25

30

0 2 4 6 8 10 12 14 16 18

0

5

10

15

20

25

30

0 2 4 6 8 10 12 14 16 18

0

5

10

15

20

25

30

0 2 4 6 8 10 12 14 16

0

5

10

15

20

25

30

Movies of Evolving Wakes Captured in a Single Shot...

What we want to do with index structure n(ζ,x,z)…1. Multi-Object-Plane imaging, each object plane (OP) are

imaged to different CCD.2. Phase shift imprinted on probe at arbitrary z, not limited to

OPs, is reconstructed.3. In single shot, z-depending transverse profile at specific ζ is

obtained.4. With multi-shots, full visualization of index object n(ζ,x,z).

Questions:5. Is the interaction length 35 cm, or longer?6. 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?

7. 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?

35 cm interaction region?1 deg. angle

L1 = ?The vacuum environment

Optical quality

window?

CCD1

CCD2

CCD3

CCD4

L0 = ?

800 nm, compressed 30 fs(?), < 1 mJ probe pulse, w0 < 1cm

M1

M2

Lens f = 75 cm

OP1 OP2 OP3 OP4

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 @ σ = 100 um 0.72 deg @ σ = 20 um

• Temporal walk-offΔt = Lθ2/2c = 38 fs @ θ = 0.5 deg 152 fs @ θ = 1 deg

• z-resolution for evolving bubbleδz = σ/θ = 5.73 mm @ σ = 100 um, θ = 1 deg 11.4 mm @ σ = 100 um, θ = 0.5 deg 2.29 mm @ σ = 20 um, θ = 0.5 deg

• ζ-resolution and range for non-evolving bubbleδζ = max{σ(θ/2+φ)/c, tpr} = max{50, 30} = 50 fsΔζ = Lθ(θ/2+φ)/c = 1.26 ps @ σ = 100 um, θ = 0.5 deg, φ = 8 deg