Femtosecond optical generation and detection of coherent acoustic phonons in GaN single crystals
We report our experimental and theoretical studies on the time-resolved generation and detection of coherent acoustic phonons (CAPs) in very high quality bulk GaN single crystals, performed using a femtosecond, two-color, all-optical pump–probe technique. A train of ultraviolet laser pulses with an energy above the GaN energy gap induced the transient electronic stress at the GaN surface, responsible for the CAP generation. Subsequent CAP oscillations, propagating without any measurable intrinsic attenuation, were observed by scanning the transient differential reflectivity signal of the near-infrared, far-below-bandgap probe beam. The above experimental results are in excellent agreement with our theoretical modeling and the published literature data.
- Research Organization:
- Univ. of Rochester, NY (United States). Lab. for Laser Energetics
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FC52-92SF19460
- OSTI ID:
- 917764
- Report Number(s):
- DOE/SF/19460-780; PRBMDO; 2007-5; 1748; TRN: US0805844
- Journal Information:
- Physical Review B, Vol. 76; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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