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

Brahm, A.; Wilms, A.; Dietz, R. J. B.; Göbel, Thorsten; Schell, Martin; Notni, Gunther; Tünnermann, Andreas

doi:10.1364/oe.22.012982

Cited by 29 publications

(15 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the terahertz regime, this can be accomplished by three possible ways. First, having an array of photoconductive antennas [70][71][72], however this approach suffers from antenna cross-talk and inefficiency problems arising from the small working-area of the antennas whilst occupying a large area. Further, such antennas arrays have only been used as detectors.…”

Section: Spatially Patterned Thz Generationmentioning

confidence: 99%

Spatial Terahertz-Light Modulators for Single-Pixel Cameras

Stantchev¹,

Pickwell‐MacPherson²

2022

Terahertz Technology

View full text Add to dashboard Cite

Terahertz imaging looks set to become an integral part of future applications from semiconductor quality control to medical diagnosis. This will only become a reality when the technology is sufficiently cheap and capabilities adequate to compete with others. Single-pixel cameras use a spatial light modulator and a detector with no spatial-resolution in their imaging process. The spatial-modulator is key as it imparts a series of encoding masks on the beam and the detector measures the dot product of each mask and the object, thereby allowing computers to recover an image via post-processing. They are inherently slower than parallel-pixel imaging arrays although they are more robust and cheaper, hence are highly applicable to the terahertz regime. This chapter dedicates itself to terahertz single-pixel cameras; their current implementations, future directions and how they compare to other terahertz imaging techniques. We start by outlining the competing imaging techniques, then we discuss the theory behind single-pixel imaging; the main section shows the methods of spatially modulating a terahertz beam; and finally there is a discussion about the future limits of such cameras and the concluding remarks express the authors’ vision for the future of single-pixel THz cameras.

show abstract

Section: Spatially Patterned Thz Generationmentioning

confidence: 99%

Spatial Terahertz-Light Modulators for Single-Pixel Cameras

Stantchev¹,

Pickwell‐MacPherson²

2022

Terahertz Technology

View full text Add to dashboard Cite

show abstract

“…They further increased the number of antenna elements to 128 (1-D) in the following work [39]. In 2014, Brahm et al, demonstrated the fabrication of a 1D PCA array (15 antenna elements) [40] using InGaAs/InAlAs multi-layer heterostructure substrate for the excitation wavelength of 1030 nm. All these works show that the fabrication of multipixel PCA array is promising for the development of high-speed THz imaging system.…”

Section: Introductionmentioning

confidence: 99%

Fabrication and Characterization of an 8 × 8 Terahertz Photoconductive Antenna Array for Spatially Resolved Time Domain Spectroscopy and Imaging Applications

et al. 2021

View full text Add to dashboard Cite

Terahertz (THz) technology is promising in several applications such as imaging, spectroscopy and communications. Among several methods in the generation and detection of THz waves, a THz timedomain system that is developed using photoconductive antennas (PCA) as emitter and detector presents several advantages such as simple alignment, low cost, high performance etc. In this work, we report the design, fabrication and characterization of a 2-D PCA array that is capable of detecting both the amplitude and phase of the THz pulse. The PCA array is fabricated using LT-GaAs and has 8 channels with 64 pixels (8 × 8). A novel approach using a spatial light modulator (SLM) to steer and focus the infrared probe beam towards pixels of the PCA array is presented. Each channel records the photocurrent generated by the THz signal (amplitude and phase) separately and frequencies up to 1.4 THz can be detected. Furthermore, the parameters such as directional time delay of the THz pulse, crosstalk between the channels etc., were characterized. Finally, we show that the proposed 2D PCA array design is flexible and can be used for accelerated THz spectral image acquisition.INDEX TERMS Multipixel detector, photoconductive antenna array, terahertz imaging, THz time-domain system.

show abstract

“…Large external biases are essential for increasing a peak THz power leading to restrictions on photoconductors, namely on its carrier relaxation times and resistance. The ternary compound InGaAs is a promising photoconductor since it operates with long-wave laser pump 1.0−1.55 µm emitted by fiber lasers that allows for fabricating low-cost and compact THz emitters for THz spectroscopy and imaging [15], [16]. When an ultrafast laser pulse with photon energy above the semiconductor bandgap strikes InGaAs, electron-hole pairs are generated at sub-surface of the semiconductor.…”

Section: Introductionmentioning

confidence: 99%

Strain-induced InGaAs/InAlAs superlattices for terahertz radiation

Ponomarev,

Yachmenev,

Pushkarev

et al. 2018

Preprint

View full text Add to dashboard Cite

We study the influence of residual strain in InGaAs/InAlAs superlattice (SL) on the ultrafast photocarrier dynamics under femtosecond laser excitation. We propose and fabricate a novel-designed strained InGaAs/InAlAs SL which allows us to obtain an ultrashort photocarrier relaxation time of τ ∼ 1.5 ps without Be-doping of the InGaAs photoconductor. We assume two dominant mechanisms to be responsible for a sharp reduction of τ : photocarriers trapping by defect levels in InAlAs barriers and increased photocarriers scattering at InGaAs/InAlAs interface roughness due to residual strain in the SL. The THz time-domain spectroscopic measurements reveal an increase in both emitted THz waveform and spectrum amplitudes with an increase of residual strain in SL. The results might be of considerable interest for accommodating the needs of THz pulsed spectroscopy and imaging in fundamental and applied branches of THz science and technology.

show abstract

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

Cited by 29 publications

References 21 publications

Spatial Terahertz-Light Modulators for Single-Pixel Cameras

Spatial Terahertz-Light Modulators for Single-Pixel Cameras

Fabrication and Characterization of an 8 × 8 Terahertz Photoconductive Antenna Array for Spatially Resolved Time Domain Spectroscopy and Imaging Applications

Strain-induced InGaAs/InAlAs superlattices for terahertz radiation

Contact Info

Product

Resources

About