Development%20of%20a%20High-Sensitivity%20Pump-Probe%20Fast%20Scanning%20Delay%20Line

1
Development of a High-Sensitivity Pump-Probe Fast
Scanning Delay Line

• Stephanie Majewski
• University of Illinois _at_ Urbana-Champaign
• University of Florida
• Faculty Mentor Professor David Reitze

2
Introduction

• Femtosecond LASERs
• Pump-Probe Spectroscopy
• Lock-in Method
• Fast-Scan System

3
(No Transcript)
4
Femtosecond Lasers

• 1 fs 0.000 000 000 000 001 s

5
What Happens in 100 Femtoseconds?

• Light Travels 30 µm
• Electrons Collide With Electrons
• Solids Begin to Melt Under Laser Irradiation
• Chemicals Dissociate

There are about as many femtoseconds in a minute
as there are minutes in the age of the universe.
6
(No Transcript)
7
(No Transcript)
8
Project Objectives

• Characterize Motion of Shaker
• Design Mirror Mount
• Optimize Performance of Shaker- Mount System
• Implement System in Pump-Probe Experiment

9
The Shaker
10
(No Transcript)
11
(No Transcript)
12
(No Transcript)
13
(No Transcript)
14
Mirror Mount
15
Obstacles ...

• Elliptical Beam Shape
• Unstable Mirror Mount
• Wobble in Drive Arm of Shaker

16
Solutions!

• Uniform Bolt Force on Mirror Yielded Circular
  Beam Shape, Mirror Rattle Minimized
• Extra Screw Added Stability to Mount
• Beam Jitter Corrected Optically

17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
Time-Resolved Nanotube Transmission Measurement

• Achieved successful fast-scan system
  implementation in pump-probe experiment
• Measurement itself unsuccessful due to intrinsic
  scattering of sample
• In future, can try using cross-polarization and
  other methods to reduce scattering.

22
Conclusion

• Developed Shaker Design for Fast Scanning System
• Characterized Shaker Motion and Corrected Beam
  Jitter to Within Acceptable Limits
• Implemented Shaker in Time-Resolved Carbon
  Nanotube Transmission Measurement

23
Acknowledgements

• Professor David Reitze
• Mark Moores and Anatoly Efimov
• Drs. Kevin Ingersent and Alan Dorsey
• NSF Research Experience for Undergraduates