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(a) Schematic of the experimental arrangement with the microstrip device, including integrated LT-GaAs emitters and detectors (gray squares), being contained inside an optical access cryostat. A–F are electrical contacts. Contacts B and E were kept at the same potential as the microstrip ground plane throughout. NIR laser pulses were focused onto position 1 for signal excitation, and positions 2 or 3 for detection of the input or output pulses to the microstrip line, respectively. (b) Schematic cross section through the switch region at position 1, in the plane orthogonal to propagation direction of terahertz pulse in the microstrip, showing signal conductor of microstrip transmission line (B), bias contact (A), and detector contact (C). (c) Schematic cross section through microstrip line showing terahertz pulse propagating as a quasi-TEM wave. Top views of switch regions are shown in Fig. 2.
Pulse shapes measured at both room temperature (dashed lines) and (full lines) at (a) the input and (b) the output switches of the microstrip device. Insets: Schematics of the LT-GaAs (gray) switch excitation regions.
Amplitude of the picosecond voltage pulses, measured at both the input and output switches, as a function of the NIR power applied to both the excitation and detection switches, at room temperature and . Lines are a quadratic fit to the data up to , showing deviation from quadratic dependence at high powers. The data and fit curves are offset by the following voltages for clarity: output: , output: , input: , and input: .
Pulse widths at FWHM of the picosecond pulses, measured at both the input and output switches, as a function of the NIR power applied to both the excitation and detection switches, at room temperature and . Lines are drawn as a guide to the eye.
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