TY - JOUR
T1 - Terahertz generation through optical rectification in reflection
AU - Kristensen, Mathias Hedegaard
AU - Herault, Emilie
AU - Zhai, Dongwei
AU - Skovsen, Esben
AU - Coutaz, Jean-Louis
PY - 2023/5/1
Y1 - 2023/5/1
N2 - In this paper, we study terahertz generation through optical rectification in reflection at normal incidence in a dielectric nonlinear crystal. We first analyze, with a nonlinear optical model, the sample parameters (thickness, absorption at both laser and terahertz wavelengths, etc.) for which a terahertz optical rectification reflection scheme is preferable to the common transmission scheme. Then, we report our experimental observations of a reflected terahertz signal generated at the surface of a ZnTe crystal. The reflected terahertz signal shares all the characteristics of a signal generated in transmission but is not limited by absorption losses in the crystal, thereby providing a broader bandwidth. At high pump laser power, the signal exhibits saturation, which is caused by the decrease of the nonlinear susceptibility due to photocarriers generated by two-photon absorption. This reflection scheme could be of great importance for terahertz microscopy of opaque materials like, e.g., humid samples or samples exhibiting strong absorption bands or to study samples for which the transmitted signal cannot be recorded.
AB - In this paper, we study terahertz generation through optical rectification in reflection at normal incidence in a dielectric nonlinear crystal. We first analyze, with a nonlinear optical model, the sample parameters (thickness, absorption at both laser and terahertz wavelengths, etc.) for which a terahertz optical rectification reflection scheme is preferable to the common transmission scheme. Then, we report our experimental observations of a reflected terahertz signal generated at the surface of a ZnTe crystal. The reflected terahertz signal shares all the characteristics of a signal generated in transmission but is not limited by absorption losses in the crystal, thereby providing a broader bandwidth. At high pump laser power, the signal exhibits saturation, which is caused by the decrease of the nonlinear susceptibility due to photocarriers generated by two-photon absorption. This reflection scheme could be of great importance for terahertz microscopy of opaque materials like, e.g., humid samples or samples exhibiting strong absorption bands or to study samples for which the transmitted signal cannot be recorded.
KW - Terahertz (THz)
KW - Optical rectification
KW - Reflection spectroscopy
KW - Nonlinear optics
UR - http://www.scopus.com/inward/record.url?scp=85158903698&partnerID=8YFLogxK
U2 - 10.1063/5.0144433
DO - 10.1063/5.0144433
M3 - Journal article
SN - 0021-8979
VL - 133
JO - Journal of Applied Physics
JF - Journal of Applied Physics
IS - 17
M1 - 173103
ER -