title: Large area photoconductive terahertz emitter for 1.55 μm excitation based on an InGaAs heterostructure.
abstract: We present scalable large area terahertz (THz) emitters based on a nanoscale multilayer InGaAs/InAlAs heterostructure and a microstructured electrode pattern. The emitters are designed for pump lasers working at the telecommunication wavelength of 1.55 μm. Electric THz fields of more than 2.5 V cm⁻¹ are reached with moderate pump powers of 80 mW, the corresponding spectrum extends up to 3 THz. The saturation characteristics have been investigated for different pump laser spot sizes. For small pump powers of less than 50 mW the emitted THz field is nearly independent of the spot size, for higher pump powers and small spot sizes a clear saturation of the generated THz pulse can be observed. Hence the use of scalable emitters is especially promising for high power fibre laser systems. The spectral content of the generated radiation is nearly independent of the parameters spot size, pump power, and bias voltage, which allows for stable operation in spectroscopic applications.
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf, PO Box 510119, D-01314 Dresden, Germany. m.mittendorff@hzdr.de
authors.forename: Martin
authors.initials: M
authors.lastname: Mittendorff
authors.forename: Ming
authors.initials: M
authors.lastname: Xu
authors.forename: Roman J B
authors.initials: RJ
authors.lastname: Dietz
authors.forename: Harald
authors.initials: H
authors.lastname: Künzel
authors.forename: Bernd
authors.initials: B
authors.lastname: Sartorius
authors.forename: Harald
authors.initials: H
authors.lastname: Schneider
authors.forename: Manfred
authors.initials: M
authors.lastname: Helm
authors.forename: Stephan
authors.initials: S
authors.lastname: Winnerl
mesh_terms: D001152:Arsenicals / Q000737:chemistry* / Q000528:radiation effects; D004553:Electric Conductivity; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005708:Gallium / Q000737:chemistry* / Q000528:radiation effects; D007204:Indium / Q000737:chemistry* / Q000528:radiation effects; D007834:Lasers; D008029:Lighting / Q000295:instrumentation*; D008422:Materials Testing; D053758:Nanoparticles / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation*; D013499:Surface Properties; D055053:Terahertz Radiation
chemical_list: D001152:Arsenicals; D007204:Indium; C043055:gallium arsenide; D005708:Gallium; C076773:indium arsenide