Abstract
The generation of subpicosecond terahertz bandwidth radiation via the illumination of nonlinear materials with visible femtosecond pulses is of interest both as a spectroscopic source and as a probe of the electronic and vibrational properties of materials. Previous studies have included terahertz emission from semiconductors1 where such emission is the result of optical rectification and/or the evolution of a transient photogenerated current.23 Terahertz emission has recently been observed from superconducting (T < Tc) YBa2Cu3O7 thin films configured as biased antennas4 and unbiased in a magnetic field.5 We describe here the first observation of terahertz emission from unbiased YBa2Cu3O7−δ (YBCO) thin films. These films are excited by 150 fs, 1.5 eV, and 3.0 eV, optical pulses for a range of temperatures, T, 4 K < T < 300 K and for a range of oxygen doping from optimally doped (δ = 0) to insulating (δ = 0.8). We demonstrate that this emission is generated by optical rectification due to the bulk electric quadrupole source term, comprising the first observation of such a source term in terahertz emission.
© 1998 Optical Society of America
PDF ArticleMore Like This
Jennifer L. W. Siders, T. R. Gosnell, S. A. Trugman, and A. J. Taylor
UF11 Ultrafast Electronics and Optoelectronics (UEO) 1997
Frank A. Hegmann, Steven H. Moffat, Robert A. Hughes, John S. Preston, Douglas Jacobs-Perkins, Chia-Chi Wang, Thomas Y. Hsiang, and Roman Sobolewski
UMD2 Ultrafast Electronics and Optoelectronics (UEO) 1995
J. L. W. Siders, T. R. Gosnell, S. A. Trugman, and A. J. Taylor
CTuP24 Conference on Lasers and Electro-Optics (CLEO:S&I) 1997