A5091487464- Terahertz technology and applications
- Photonic and Optical Devices
- Semiconductor Quantum Structures and Devices
- Superconducting and THz Device Technology
- Spectroscopy and Laser Applications
- Semiconductor Lasers and Optical Devices
- Gyrotron and Vacuum Electronics Research
- Plasmonic and Surface Plasmon Research
- Quantum and electron transport phenomena
- Magnetic properties of thin films
- Mechanical and Optical Resonators
- Advanced Fiber Laser Technologies
- Photonic Crystals and Applications
Technical University of Darmstadt
2017-2023
Quintessence Biosciences (United States)
2023
Ruhr University Bochum
2023
We demonstrate antenna-coupled spintronic terahertz (THz) emitters excited by 1550 nm, 90 fs laser pulses. Antennas are employed to optimize THz outcoupling and frequency coverage of ferromagnetic/nonmagnetic metallic structures. directly compare the devices those without antennas. Using a 200 μm H-dipole antenna an ErAs:InGaAs photoconductive receiver, we obtain 2.42-fold larger peak-peak signal, bandwidth 4.5 THz, increase in peak dynamic range (DNR) from 53 dB 65 dB. A 25 slotline offered...
Superlattice structures of In(Al)GaAs with localized ErAs trap centers feature excellent material properties for terahertz (THz) generation and detection. The carrier lifetime these materials as emitter receiver has been measured 1.76 ps 0.39 ps, respectively. Packaged photoconductors driven by a 1550 nm, 90 fs commercial Toptica "TeraFlash pro" system 4.5 THz single shot bandwidth more than 60 dB dynamic range. emitted power the ErAs:In(Al)GaAs versus laser recorded pyroelectric detector...
Abstract Surface states generally degrade semiconductor device performance by raising the charge injection barrier height, introducing localized trap states, inducing surface leakage current, and altering electric potential. We show that giant built-in field created can be harnessed to enable passive wavelength conversion without utilizing any nonlinear optical phenomena. Photo-excited plasmons are coupled generate an electron gas, which is routed a nanoantenna array through states. The...
We introduce a new scheme for the detection of terahertz pulses based on frequency selective optoelectronic downconversion its individual modes with continous-wave (CW) ErAs:InGaAs photoconductive antenna (PCA) driven by comb-based CW photonic signal. The can be used as metrology tool analysis fundamental resolution and stability limits mode-locked-lasers (MLLs) that drives them, well an ultra-high-resolution measurement technique components or gas spectroscopy. demonstrate both applications...
A slotted Y-branch laser diode that emits two spectral modes at a difference frequency of about 1 THz is investigated in the context photonic based cw-THz measurements. The beating emitted light can be tuned by ±10.5 GHz around changing applied current, which allows for potentially fast second window ±6.5 was found 850 GHz. Pointwise scanning demonstrated with thickness determination HRFZ-Si wafer samples as possible application scenario.
In this work, a monolithic Y-branch laser diode is used for continuous wave Terahertz generation and detection. The output of the fiber coupled, amplified fed into photoconductor based cw setup. While system can be time domain measurements using coupled delay stage, we'll present sample thickness determination on current induced frequency sweeping without stage.
We demonstrate a spectrometer capable of measuring terahertz time domain transmission and reflection spectroscopy simultaneously in single setup. This facilitates highly accurate determination optical material parameters the geometric thickness by taking advantage both geometries. The system is also suitable for parameter extraction materials when data from geometry cannot be extracted characterizing non-time-invariant devices such as isolators.
We present a simple analytical model for the dispersion of pulse radiated by self-complementary logarithmic-periodic antenna. The predicts variation in spectral phase, and explains underlying mechanism behind it. phase predicted is compared with measured Terahertz (THz) Time Domain System (TDS) that uses same type
This paper reviews progress on ErAs:In(Al)GaAs photomixers for operation with telecom lasers at 1550 nm, including linearity and absorption coefficient measurements, specifications, packaging example, applications in vector spectrometry. We have achieved a receiver noise equivalent power as low 1.81 fW/Hz 188 GHz under continuous-wave bandwidth of more than 6 THz peak dynamic range 89 dB pulsed operation.
In the last few years, many advances have been made in demonstration of high-average power pulsed THz sources; however, little effort has to study compatible sensitive field-resolved detectors. Here, we investigate ErAs:InAlGaAs photoconductive receivers optimized for a probe wavelength 1030 nm and thus suitable new class high-power ultrafast Ytterbium-based laser sources generation detection. The performance receiver is tested with few-cycle source high average up 20 mW dynamic range...
We present active, telecom-wavelength compatible THz components with enhanced performance by introducing ErAs precipitates. First, we review how an monolayer in between p-i-n diodes enables serial connection of these diodes, reducing the total capacitance and thus decoupling existing trade-off RC- transit time roll-off. In second part paper, latest results ErAs:In(Al)GaAs photoconductive devices are shown. Continous-wave (CW) receivers show almost flat frequency response up to 0.5 a noise...
We study the impact of an external electric DC field on antenna-coupled spintronic THz emitters driven by a 90 fs, 1550 nm laser oscillator. Simultaneous application and magnetic shows quadratic decrease in peak-peak pulse with increase bias voltage. ascribe this to Joule heating caused current flowing through material.
This work investigates a monolithic slotted Y-branch diode laser as beating source to drive continuous wave Terahertz spectrometer. Both arms of the exhibit spectral selective feedback, which causes simultaneous emission at two frequencies. At first, thorough optical characterisation with 5400 individual setpoints is performed find best point operation. Two operational regimes difference frequencies 1 THz ± 10.5 GHz and 0.85 6.5 were identified. While validating cw-THz spectrometer, it was...
We use a slotted Y-branch Laser for Terahertz thickness measurements of high resistive float zone silicon wafers different thicknesses. The laser provides two-color emission in the 1550 nm region with an optical beat frequency 1 THz. It is used as photonic source continuous wave radiation. Frequency tuning obtained through segment current individual branches. determine sample´s refractive index and by MSE fitting theoretical etalon transmission to experimental results without additional knowledge.
We present an investigation of ErAs:InAlGaAs photoconductive antenna receiver optimized for 1030 nm probe pulses at 24 mW THz power and show a dynamic range 92 dB in 10 s measurement time. The saturation behavior under high average is studied as well.