Home › Analytical Chem › Measurement of Coherence Decay in GaMnAs Using Femtosecond Four-wave Mixing
Analytical Chem JoVE (Open Access) Citable · DOI

Measurement of Coherence Decay in GaMnAs Using Femtosecond Four-wave Mixing

DOI: 10.3791/51094-v
What you'll learn
  • ✓ Set up and optimize femtosecond four-wave mixing apparatus for coherence measurements
  • ✓ Perform spectrally-resolved and time-resolved FWM measurements on semiconductor samples
  • ✓ Extract interband dephasing times and coherence decay properties from GaMnAs
Protocol

The technique of femtosecond four-wave mixing is described, including spectrally-resolved and time-resolved configurations. We illustrate the utility of this technique for the investigation of crucial physical properties in the III-V diluted magnetic semiconductors, afforded by its nonlinearity and high temporal resolution.

Difficulty
advanced
Total time
~4–6 hours per sample (including apparatus alignment, pulse optimization, and multi-configuration measurements)

Steps

1
Overview optical apparatus and beam paths

Understand the layout of the femtosecond laser system, optical components, and beam steering necessary for four-wave mixing experiments. Familiarize yourself with the spectrally-resolved and time-resolved detection configurations.

▶ 03:19
2
Measure and optimize femtosecond laser pulses

Characterize pulse duration and spectral properties using autocorrelation or similar techniques, then optimize laser output to achieve minimal pulse width required for coherence measurements.

▶ 06:10
3
Prepare GaMnAs sample for measurement

Mount and position the diluted magnetic semiconductor sample in the measurement apparatus, ensuring proper optical alignment and thermal stability.

▶ 08:38
4
Execute four-wave mixing signal measurement

Perform FWM measurements by directing femtosecond pulses onto the sample and collecting the nonlinear optical signal using the spectrally-resolved or time-resolved detection configuration.

▶ 10:09
5
Analyze interband dephasing times from FWM data

Extract and interpret coherence decay measurements to determine interband dephasing times and evaluate crucial physical properties of the GaMnAs semiconductor.

▶ 12:27
💬 Comments coming soon