THz excitation and detection apparatus located inside the dilution refrigerator.
Schematic diagram of a THz CPW formed on a continuous LT-GaAs surface (dark regions) comprising a gap–center conductor–gap of dimensions 20 μm–30 μm–20 μm. PC switches 1–4 are defined by 30-μm-width probe arms, separated from the ground planes by a 5 μm gap. Switch pairs are separated by 1.2 mm.
The layer structure of a 2DES heterostructure monolithically integrated with a photoconductive LT-GaAs layer, grown by MBE.
(a) Input (solid) and output (dashed) THz pulses measured in the dilution refrigerator at 200 mK (pulse delay artificially removed for comparison); (b) and (c) spatial maps recorded at 400 mK and 12 T magnetic field, of the pump switch photocurrent and the corresponding peak-to-peak transmitted THz signal amplitude, respectively.
A THz CPW with a 2DES mesa integrated into the center conductor. The second mesa is present to prevent over-etching of the 2DES region when etching down to the LT-GaAs surface.
Input (solid) and output (dashed) THz pulses measured at: (a) room temperature and (b) 4 K, respectively. Inset (b) area under the output pulse as a percentage of the input pulse for the slotline (circles) and coplanar (squares) guided modes, as a function of temperature; and (c) transmitted THz signal amplitude as a function of magnetic field (symbols) compared with the 2-terminal mesa resistance (line), measured at a dilution refrigerator temperature of 200 mK.
Article metrics loading...
Full text loading...