Ultrafast laser-semiconductor interactions
- Phillips Lab., Kirtland Air Force Base, NM (United States)
Studies of the ultrafast (< 100 fs) interactions of infrared, sub-100 fs laser pulses with IR, photosensitive semiconductor materials InGaAs, InSb, and HgCdTe are reported. Both the carrier dynamics and the associated Terahertz radiation from these materials are discussed. The most recent developments of femtosecond (< 100 fs) Optical Parametric Oscillators (OPO) has extended the wavelength range from the visible to 5.2 {mu}m. The photogenerated semiconductor free carrier dynamics are determined in the 77 to 300{degrees}K temperature range using the Transmission Correlation Peak (TCP) method. The electron-phonon scattering times are typically 200 - 600 fs. Depending upon the material composition and substrate on which the IR crystalline materials are deposited, the nonlinear TCP absorption gives recombination rates as fast as 10`s of picoseconds. For the HgCdTe, there exists a 400 fs electron-phonon scattering process along with a much longer 3600 fs loss process. Studies of the interactions of these ultrashort laser pulses with semiconductors produce Terahertz (Thz) radiative pulses. With undoped InSb, there is a substantial change in the spectral content of this THz radiation between 80 - 260{degrees}K while the spectrum of Te-doped InSb remains nearly unchanged, an effect attributed to its mobility being dominated by impurity scattering. At 80{degrees}K, the terahertz radiation from undoped InSb is dependent on wavelength, with both a higher frequency spectrum and much larger amplitudes generated at longer wavelengths. No such effect is observed at 260{degrees}K. Finally, new results on the dependence of the emitted THz radiation on the InSb crystal`s orientation is presented.
- Research Organization:
- International Society for Optical Engineering, Washington, DC (United States)
- OSTI ID:
- 552081
- Report Number(s):
- CONF-9510106-Vol.2714; TRN: 98:008989
- Resource Relation:
- Conference: 27. annual symposium on optical materials for high power lasers, Boulder, CO (United States), 30 Oct - 1 Nov 1995; Other Information: PBD: [1996]; Related Information: Is Part Of Laser-induced damage in optical materials: 1995. Twenty-seventh annual Boulder damage symposium, proceedings; Bennett, H.E.; Guenther, A.H.; Kozlowski, M.R.; Newnam, B.E.; Soileau, M.J. [eds.]; PB: 794 p.
- Country of Publication:
- United States
- Language:
- English
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