Improving the dynamic range of InGaAs-based THz detectors by localized beryllium doping: up to 70 dB at 3 THz.

In this Letter, we report on photoconductive terahertz (THz) detectors for 1550 nm excitation based on a low-temperature-grown InGaAs/InAlAs superlattice with a localized beryllium doping profile. With this approach, we address the inherent lifetime-mobility trade-off that arises, since trapping centers also act as scattering sites for photo-excited electrons. The localized doping of the InAlAs barrier only leads to faster electron trapping for a given mobility.

Terahertz quasi time-domain spectroscopy based on telecom technology for 1550 nm.

We present a fiber-coupled terahertz quasi time-domain spectroscopy system driven by a laser with a central wavelength of 1550 nm. By using a commercially available multimode laser diode in combination with state-of-the-art continuous wave antennas, a bandwidth of more than 1.8 THz is achieved.

Fiber-coupled transceiver for terahertz reflection measurements with a 4.5 THz bandwidth.

We present a fiber-coupled transceiver for THz time-domain spectroscopy, which combines an emitter and a receiver on a single photoconductive chip. With a bandwidth of 4.5 THz and a peak dynamic range larger than 70 dB, it allows for THz reflection measurements under normal incidence.

Absolute terahertz power measurement of a time-domain spectroscopy system.

We report on, to the best of our knowledge, the first absolute terahertz (THz) power measurement of a photoconductive emitter developed for time-domain spectroscopy (TDS). The broadband THz radiation emitted by a photoconductor optimized for the excitation with 1550-nm femtosecond pulses was measured by an ultrathin pyroelectric thin-film (UPTF) detector. We show that this detector has a spectrally flat transmission between 100 GHz and 5 THz due to special conductive electrodes on both sides of the UPTF.

All fiber-coupled THz-TDS system with kHz measurement rate based on electronically controlled optical sampling.

We demonstrate a completely fiber-coupled terahertz (THz) time-domain spectrometer (TDS) system based on electronically controlled optical sampling with two erbium-doped femtosecond fiber lasers at a central wavelength of 1560 nm. The system employs optimized InGaAs/InAlAs photoconductive antennas for THz generation and detection. With this system, we achieve measurement rates of up to 8 kHz and up to 180 ps scan range.

Influence and adjustment of carrier lifetimes in InGaAs/InAlAs photoconductive pulsed terahertz detectors: 6 THz bandwidth and 90dB dynamic range.

We investigate the influence of Beryllium (Be) doping on the performance of photoconductive THz detectors based on molecular beam epitaxy (MBE) of low temperature (LT) grown In(0.53)Ga(0.47)As/In(0.

Terahertz transceiver concept.

We present a photoconductive terahertz transceiver based on a modulation of the optical pulses used for generation and detection at different rates. External modulation of the THz pulses is not required as opposed to previously reported approaches. Devices from fiber-optic technology are used, providing flexibility and stability to the system.

Multichannel terahertz time-domain spectroscopy system at 1030 nm excitation wavelength.

We present Terahertz (THz) imaging with a 1D multichannel time-domain spectroscopy (TDS) system which operates with a photoconductive array of 15 detection channels excited by a 1030 nm femtosecond fiber laser. The emitter and detector are photoconductive antennas based on InGaAs/InAlAs multi-layer heterostructures (MLHS). We characterized the THz optics and the resolution of the system.

Telecom technology based continuous wave terahertz photomixing system with 105 decibel signal-to-noise ratio and 3.5 terahertz bandwidth.

A modified photoconductive receiver significantly improves the performance of photomixing-based continuous wave (cw) THz systems driven at the optical telecommunication wavelength of 1.5 μm. The achieved signal-to-noise ratio of 105 dB at 100 GHz and 70 dB at 1 THz, both for an integration time of 200 ms, are to our knowledge the highest numbers reported in literature for any optoelectronic cw THz system, including classical setups operating at 800 nm.

Large area photoconductive terahertz emitter for 1.55 μm excitation based on an InGaAs heterostructure.

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.

THz generation at 1.55 µm excitation: six-fold increase in THz conversion efficiency by separated photoconductive and trapping regions.

We present first results on photoconductive THz emitters for 1.55µm excitation. The emitters are based on MBE grown In0.