Generation of THz transients by photoexcited single-crystal GaAs meso-structures
- Univ. of Rochester, NY (United States)
- Research Center Jülich (Germany). Peter Grünberg Institut (PGI-9); Jülich-Aachen Research Alliance (JARA) Jülich, Germany
- Jülich-Aachen Research Alliance (JARA) Jülich, Germany; Research Center Jülich (Germany). Peter Grünberg Institut (PGI-9)
- Univ. of Rochester, NY (United States). Lab. for Laser Energetics; Institute of Electron Technology, Warszawa (Poland)
We report a sub-picosecond photoresponse and THz transient generation of GaAs single-crystal mesoscopic platelets excited by femtosecond optical pulses. Our structures were fabricated by a top-down technique, by patterning an epitaxial, 500-nm-thick GaAs film grown on top of an AlAs sacrificial layer and then transferring the resulting etched away 10 x 20-μm2 platelets onto an MgO substrate using a micropipette. The freestanding GaAs devices, incorporated into an Au coplanar strip line, exhibited extremely low dark currents and ~0.4 % detection efficiency at 10 V bias. The all-optical, pump–probe carrier dynamics analysis showed that, for 800-nm-wavelength excitation, the intrinsic relaxation of photocarriers featured a 310-fs-wide transient with a 290 fs fall time. We have also carried out a femtosecond, timeresolved electro-optic characterization of our devices and recorded along the transmission line the electrical transients as short as ~600 fs, when the platelet was excited by a train of 100-fs-wide, 800-nm-wavelength optical laser pulses. The platelets have been also demonstrated to be very efficient generators of free-space propagating THz transients with the spectral bandwidth exceeding 2 THz.The presented performance of the epitaxial, freestanding GaAs meso-structured photodevices makes them uniquely suitable for THz-frequency optoelectronic applications, ranging from ultrafast photodetectors to THz-bandwidth optical-to-electrical transducers and photomixers.
- Research Organization:
- Univ. of Rochester, NY (United States). Lab. for Laser Energetics
- Sponsoring Organization:
- USDOE; US Army Research Office (ARO)
- Grant/Contract Number:
- FC52-08NA28302; W911NF-12-2-0076
- OSTI ID:
- 1144012
- Report Number(s):
- DOE/NA/28302-1176; 2014-168; 2142
- Journal Information:
- Applied Physics. B, Lasers and Optics, Vol. 113, Issue 3; ISSN 0946-2171
- Publisher:
- SpringerCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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