@article{0ed788f120f94853a8e01e3e5b97076a,
title = "Terahertz enhancement from terahertz-radiation-assisted large aperture photoconductive antenna",
abstract = "The observation of enhanced terahertz (THz) wave generation from the large aperture photoconductive (PC) antenna excited by both a femtosecond pump beam and a collinearly propagating ZnTe-pregenerated THz wave is reported within this paper. An analysis based on both the calculated and experimental results demonstrated that the superposition acts as the main physical mechanism of this THz enhancement effect due to the dominant contribution from the rapid change in photoexcited carrier density. A prerequisite for the THz enhancement requires that the polarization of the applied bias and the ZnTe-pregenerated THz should be identical in order to have a constructive superposition. Therefore, this observation introduces the possibility of recycling the unused portion of the pump beam to further improve the THz radiation. The enhancement effect could be optimized by changing the thickness of ZnTe, which could affect the photoexcited-free-carrier absorption of THz in the PC antenna and the bandwidth of final enhanced THz radiation.",
author = "Yaohui Gao and Chen, {Meng Ku} and Stuart Yin and Paul Ruffin and Christina Brantley and Eugene Edwards",
note = "Funding Information: Authors greatly acknowledge the partial financial support of this work by an ONR basic research program (N000140810538). FIG. 1. Schematic diagram of the experimental setup. WP denotes Wollaston prism and λ / 4 denotes the quarter-wave plate. FIG. 2. (a) THz waveforms obtained by scanning probe beam delay from PC antenna and PC antenna + ZnTe system, respectively. (b) The corresponding spectra obtained from the Fourier transform. FIG. 3. THz waveforms from PC antenna + ZnTe system obtained by experiment and calculation, respectively. FIG. 4. THz waveform from PC antenna + ZnTe system after a sapphire wafer-induced phase change. FIG. 5. THz waveforms generated from PC antenna with bias and reversed bias, respectively. FIG. 6. THz waveforms from PC antenna + ZnTe system with destructive superposition obtained by calculation and experiment, respectively. FIG. 7. (a) 1 mm thick ZnTe generated THz waveforms after transmitting PC antenna with and without pump beam illumination, respectively. (b) 0.2 mm thick ZnTe generated THz waveforms after transmitting PC antenna with and without pump beam illumination, respectively. FIG. 8. The transmitted pump beam energy with the function the thickness of ZnTe. ",
year = "2011",
month = feb,
day = "1",
doi = "10.1063/1.3544044",
language = "English (US)",
volume = "109",
journal = "Journal of Applied Physics",
issn = "0021-8979",
publisher = "American Institute of Physics Publising LLC",
number = "3",
}