Terahertz photonics

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Conductivity of nanoporous InP membranes investigated using terahertz spectroscopy

IRMMW-THz2007 - Conference Digest of the Joint 32nd International Conference on Infrared and Millimetre Waves, and 15th International Conference on Terahertz Electronics (2007) 224-225

Authors:

SKE Merchant, J Lloyd-Hughes, L Sirbu, IM Tiginyanu, P Parkinson, LM Herz, MB Johnston

Abstract:

We have investigated the conductivity of equilibrium and photoexcited electrons in nanoporous indium phosphide (InP) of various porosities and of two orientations: (100) and (111). We observed an enhanced transmission through the nanoporous samples compared with bulk InP, resulting from a suppression of the conductivity by the pores. The frequency-dependent conductivity was extracted numerically from the transmission data. We examined the dynamical conductivity of photoexcited carriers using optical-pump THz-probe spectroscopy. After the rapid photoexcitation of electrons, the timeresolved conductivity was observed to decay slowly, with carrier recombination lifetimes exceeding 1 ns for all (100)- and (111)-oriented samples.
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Enhancement of ultrafast conductivity in surface-passivated GaAs

Optics InfoBase Conference Papers (2007)

Authors:

J Lloyd-Hughes, SKE Merchant, L Fu, HH Tan, C Jagadish, E Castro-Camus, MB Johnston

Abstract:

Optical-pump/terahertz-probe spectroscopy and terahertz emission spectroscopy were used to measure the conductivity and surface electric field change resulting from passivating the surface of GaAs. An enhanced terahertz radiation generation from passivated photoconductive antenna was observed. © 2006 Optical Society of America.
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Plasmonics: Superfocusing of terahertz waves

Nature Photonics 1:1 (2007) 14-15
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Terahertz probe of carrier trapping in polymer transistors

Optics InfoBase Conference Papers (2007)

Authors:

J Lloyd-Hughes, T Richards, H Sirringhaus, E Castro-Camus, LM Herz, MB Johnston

Abstract:

The trapped charge density at the polymer-insulator boundary of polymer transistors was monitored by terahertz time-domain spectroscopy. Additionally, the thermal removal of trapped holes and the light-induced transmission change were studied. © 2006 Optical Society of America.
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Transmission and emission terahertz time-domain spectroscopy with polarisation-sensitive photoconductive receivers

IRMMW-THz2007 - Conference Digest of the Joint 32nd International Conference on Infrared and Millimetre Waves, and 15th International Conference on Terahertz Electronics (2007) 210-211

Authors:

E Castro-Camus, J Lloyd-Hughes, L Fu, HH Tan, C Jagadish, MB Johnston

Abstract:

In this contribution a detailed characterisation of the performance of three-contact polarisation-sensitive terahertz detectors will be discussed. Furthermore the appropriate mathematical formalism required for the analysis of polarisation-resolved THz measurements will be presented. In addition, measurements of the polarisation-resolved transmission of quartz and polarisation-resolved emission of (110) ZnTe will be shown in order to illustrate the relevance of polarisation in time domain measurements. Finally perspectives on experiments that require polarisation sensitivity will be discussed.
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