scholarly journals Diffraction-limited ultrabroadband terahertz spectroscopy

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
M. Baillergeau ◽  
K. Maussang ◽  
T. Nirrengarten ◽  
J. Palomo ◽  
L. H. Li ◽  
...  
Keyword(s):  
Electric Fields ◽  
Dynamic Range ◽  
Terahertz Spectroscopy ◽  
Thz Spectroscopy ◽  
Thz Radiation ◽  
Large Area ◽  
Broadband Radiation ◽  
Strong Focusing ◽  
Spectroscopy System ◽  
Photoconductive Emitter

Abstract Diffraction is the ultimate limit at which details of objects can be resolved in conventional optical spectroscopy and imaging systems. In the THz spectral range, spectroscopy systems increasingly rely on ultra-broadband radiation (extending over more 5 octaves) making a great challenge to reach resolution limited by diffraction. Here, we propose an original easy-to-implement wavefront manipulation concept to achieve ultrabroadband THz spectroscopy system with diffraction-limited resolution. Applying this concept to a large-area photoconductive emitter, we demonstrate diffraction-limited ultra-broadband spectroscopy system up to 14.5 THz with a dynamic range of 103. The strong focusing of ultrabroadband THz radiation provided by our approach is essential for investigating single micrometer-scale objects such as graphene flakes or living cells and besides for achieving intense ultra-broadband THz electric fields.

A 570-630 GHz FREQUENCY DOMAIN TERAHERTZ SPECTROSCOPY SYSTEM BASED ON A BROADBAND QUASI-OPTICAL ZERO BIAS SCHOTTKY DIODE DETECTOR

2011 ◽  
Vol 20 (03) ◽  
pp. 629-638 ◽  
Author(s):  
LEI LIU ◽  
JEFFREY L. HESLER ◽  
ROBERT M. WEIKLE ◽  
TAO WANG ◽  
PATRICK FAY ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Schottky Diode ◽  
Terahertz Spectroscopy ◽  
Solid Phase ◽  
Thz Spectroscopy ◽  
Thz Radiation ◽  
Metal Mesh ◽  
Zero Bias ◽  
Diode Detector ◽  
Spectroscopy System

We report a room temperature 570-630 GHz frequency domain terahertz (THz) spectroscopy system developed on the basis of a broadband quasi-optical zero bias Schottky diode detector. The detector is designed to cover the frequency range of 100 GHz to nearly 900 GHz. A responsivity of 300-1000 V/W has been measured, and the noise equivalent power (NEP) is estimated to be 5-20 pW/√Hz based on the measurements of similar detectors. For a prototype demonstration, the frequency domain THz spectroscopy system was operated within the region of 570-630 GHz using a VDI (Virginia Diodes, Inc.) frequency extension module (FEM) to provide the THz radiation. Mylar thin films with different thicknesses and THz metal mesh filters have been measured using this system, demonstrating a measurement accuracy of ~2%. This system has been applied to measure biomolecules in liquid-phase, and nano-material samples in solid-phase. Initial results and discussion are presented.

scholarly journals Contactless In Situ Electrical Characterization Method of Printed Electronic Devices with Terahertz Spectroscopy

2019 ◽  
Author(s):  
Mariia Zhuldybina ◽  
Xavier Ropagnol ◽  
Charles Trudeau ◽  
Martin Bolduc ◽  
Ricardo J. Zednik ◽  
...  
Keyword(s):  
Quality Control ◽  
Terahertz Spectroscopy ◽  
Low Cost ◽  
Electronic Devices ◽  
Electrical Characterization ◽  
Conductivity Measurement ◽  
Thz Spectroscopy ◽  
Thz Radiation ◽  
Simple Strategy

Printed electronic devices are attracting significant interest due to their versatility and low cost; however, quality control during manufacturing is a significant challenge, preventing the widespread adoption of this promising technology. We show that terahertz (THz) radiation can be used for the in situ inspection of printed electronic devices, as confirmed through a comparison with conventional electrical conductivity methods. Our in situ method consists of printing a simple test pattern exhibiting a distinct signature in the THz range that enables the precise characterization of {the static} electrical conductivities of the printed ink. We demonstrate that contactless dual-wavelength THz spectroscopy analysis, which requires only a single THz measurement, is more precise and repeatable than the conventional four-point probe conductivity measurement method. Our results open the door to a simple strategy for performing contactless quality control in real time of printed electronic devices at any stage of its production line.

scholarly journals Contactless In Situ Electrical Characterization Method of Printed Electronic Devices with Terahertz Spectroscopy

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 444 ◽  
Author(s):  
Mariia Zhuldybina ◽  
Xavier Ropagnol ◽  
Charles Trudeau ◽  
Martin Bolduc ◽  
Ricardo Zednik ◽  
...  
Keyword(s):  
Quality Control ◽  
Terahertz Spectroscopy ◽  
Low Cost ◽  
Electronic Devices ◽  
Electrical Characterization ◽  
Conductivity Measurement ◽  
Thz Spectroscopy ◽  
Thz Radiation ◽  
Simple Strategy

Printed electronic devices are attracting significant interest due to their versatility and low cost; however, quality control during manufacturing is a significant challenge, preventing the widespread adoption of this promising technology. We show that terahertz (THz) radiation can be used for the in situ inspection of printed electronic devices, as confirmed through a comparison with conventional electrical conductivity methods. Our in situ method consists of printing a simple test pattern exhibiting a distinct signature in the THz range that enables the precise characterization of the static electrical conductivities of the printed ink. We demonstrate that contactless dual-wavelength THz spectroscopy analysis, which requires only a single THz measurement, is more precise and repeatable than the conventional four-point probe conductivity measurement method. Our results open the door to a simple strategy for performing contactless quality control in real time of printed electronic devices at any stage of its production line.

The Applications of Terahertz Spectroscopy in Functional Optical Materials Researches

2013 ◽  
Vol 320 ◽  
pp. 133-137
Author(s):  
Xiao Jian Fu ◽  
Ji Zhou
Keyword(s):  
Optical Materials ◽  
Yttrium Aluminum Garnet ◽  
Terahertz Spectroscopy ◽  
Functional Materials ◽  
Thz Spectroscopy ◽  
Thz Radiation ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Resolved ◽  
Injection Process ◽  
Security Inspection

Terahertz radiation refers to the electromagnetic wave whose frequency is usually defined between 0.1 and 10 THz (1 THz=1012 Hz). With the development of the emission and detection technologies of THz radiation, terahertz time-domain spectroscopy (THz-TDS) has been widely used in medical diagnosis, security inspection and materials characterization. In this paper, we introduced briefly the progress of terahertz measurement technologies, and then reviewed the applications of THz spectra in functional materials researches. As two important functional optical materials, TiO2 nanoparticles and yttrium aluminum garnet (YAG) crystal have been investigated with THz-TDS. We introduced the electron injection process in TiO2 studied by time resolved THz spectroscopy which is reported in the literature, and then presented our own work, the THz optical constants of undoped and Tm3+ doped YAG crystals.

Continuous-wave Terahertz Spectroscopy System Based on Photodiodes

PIERS Online ◽  
2010 ◽  
Vol 6 (4) ◽  
pp. 390-394 ◽  
Author(s):  
Tadao Nagatsuma ◽  
Akira Kaino ◽  
Shintaro Hisatake ◽  
Katsuhiro Ajito ◽  
Ho-Jin Song ◽  
...  
Keyword(s):  
Continuous Wave ◽  
Terahertz Spectroscopy ◽  
Spectroscopy System

scholarly journals Temperature dependent poly(L-lactide) crystallization investigated by Fourier transform terahertz spectroscopy

2021 ◽  
Author(s):  
Seiichiro Ariyoshi ◽  
Satoshi Ohnishi ◽  
Hikaru Mikami ◽  
Hideto Tsuji ◽  
Yuki Arakawa ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Absorption Spectra ◽  
Terahertz Spectroscopy ◽  
Thz Spectroscopy ◽  
Frequency Range ◽  
Temperature Dependent ◽  
Thz Absorption

Poly(L-lactide) (PLLA) was investigated by Fourier transform terahertz (THz) spectroscopy over the frequency range of 1.0 – 8.5 THz. THz absorption spectra were acquired for PLLA samples isothermally crystallized at...

scholarly journals Optoelectronic frequency-modulated continuous-wave terahertz spectroscopy with 4 THz bandwidth

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lars Liebermeister ◽  
Simon Nellen ◽  
Robert B. Kohlhaas ◽  
Sebastian Lauck ◽  
Milan Deumer ◽  
...  
Keyword(s):  
Fiber Optics ◽  
Continuous Wave ◽  
Dynamic Range ◽  
Terahertz Spectroscopy ◽  
Beat Signal ◽  
Photonic Integration ◽  
Terahertz Time Domain Spectroscopy ◽  
Destructive Testing ◽  
Optical Delay ◽  
Broadband Terahertz

AbstractBroadband terahertz spectroscopy enables many promising applications in science and industry alike. However, the complexity of existing terahertz systems has as yet prevented the breakthrough of this technology. In particular, established terahertz time-domain spectroscopy (TDS) schemes rely on complex femtosecond lasers and optical delay lines. Here, we present a method for optoelectronic, frequency-modulated continuous-wave (FMCW) terahertz sensing, which is a powerful tool for broadband spectroscopy and industrial non-destructive testing. In our method, a frequency-swept optical beat signal generates the terahertz field, which is then coherently detected by photomixing, employing a time-delayed copy of the same beat signal. Consequently, the receiver current is inherently phase-modulated without additional modulator. Owing to this technique, our broadband terahertz spectrometer performs (200 Hz measurement rate, or 4 THz bandwidth and 117 dB peak dynamic range with averaging) comparably to state-of-the-art terahertz-TDS systems, yet with significantly reduced complexity. Thickness measurements of multilayer dielectric samples with layer-thicknesses down to 23 µm show its potential for real-world applications. Within only 0.2 s measurement time, an uncertainty of less than 2 % is achieved, the highest accuracy reported with continuous-wave terahertz spectroscopy. Hence, the optoelectronic FMCW approach paves the way towards broadband and compact terahertz spectrometers that combine fiber optics and photonic integration technologies.

scholarly journals First Light And Reionization Epoch Simulations (FLARES) – I. Environmental dependence of high-redshift galaxy evolution

2020 ◽  
Vol 500 (2) ◽  
pp. 2127-2145
Author(s):  
Christopher C Lovell ◽  
Aswin P Vijayan ◽  
Peter A Thomas ◽  
Stephen M Wilkins ◽  
David J Barnes ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
Galaxy Formation ◽  
Dynamic Range ◽  
High Redshift ◽  
Formation Rate ◽  
Mass Function ◽  
Distribution Functions ◽  
Large Area ◽  
Composite Distribution ◽  
Environmental Dependence

ABSTRACT We introduce the First Light And Reionisation Epoch Simulations (FLARES), a suite of zoom simulations using the EAGLE model. We resimulate a range of overdensities during the Epoch of Reionization (EoR) in order to build composite distribution functions, as well as explore the environmental dependence of galaxy formation and evolution during this critical period of galaxy assembly. The regions are selected from a large $(3.2 \, \mathrm{cGpc})^{3}$ parent volume, based on their overdensity within a sphere of radius 14 h−1 cMpc. We then resimulate with full hydrodynamics, and employ a novel weighting scheme that allows the construction of composite distribution functions that are representative of the full parent volume. This significantly extends the dynamic range compared to smaller volume periodic simulations. We present an analysis of the galaxy stellar mass function (GSMF), the star formation rate distribution function (SFRF), and the star-forming sequence (SFS) predicted by FLARES, and compare to a number of observational and model constraints. We also analyse the environmental dependence over an unprecedented range of overdensity. Both the GSMF and the SFRF exhibit a clear double-Schechter form, up to the highest redshifts (z = 10). We also find no environmental dependence of the SFS normalization. The increased dynamic range probed by FLARES will allow us to make predictions for a number of large area surveys that will probe the EoR in coming years, carried out on new observatories such as Roman and Euclid.

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