A terahertz time-domain spectrometer is employed to study different birefringent samples. We develop a method based on the temporal waveform and the impulse response of a sample to map the anisotropy of their inner structure. To validate our algorithm, we study the polarization-affecting structure of various classes of materials such as crystals, plastics, and natural products. Among all samples we observe the largest birefringence for a rutile crystal with Deltan=3.3 at 1 THz.
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http://dx.doi.org/10.1364/ao.48.002037 | DOI Listing |
Nanophotonics
April 2024
Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, F-75005, Paris, France.
Spintronic terahertz emitters (STEs), based on optical excitation of nanometer thick ferromagnetic/heavy metal (FM/HM) heterojunctions, have become important sources for the generation of terahertz (THz) pulses. However, the efficiency of the optical-to-THz conversion remains limited. Although optical techniques have been developed to enhance the optical absorption, no investigations have studied the application of THz cavities.
View Article and Find Full Text PDFThe paper presents a thorough investigation into the design of a Modified Core Hexa-Deca Photonic Crystal Fiber (MHD-PCF) with adjustable features to regulate dispersion and birefringence. At the target wavelength of 1550 nm, the suggested MHD-PCF exhibits extraordinary optical properties, including an ultra-high negative dispersion coefficient of - 7755 ps/(nm km) and significant birefringence of 1.905 × 10.
View Article and Find Full Text PDFSci Rep
November 2024
Photonics Device Physics Laboratory, Department of Physics, Yonsei University, Seoul, 120-749, South Korea.
We thoroughly investigated the optical properties of surfactant-free deoxyribonucleic acid (SF-DNA) solid films across a broad spectral gamut from ultraviolet (UV) to terahertz (THz). Demonstrating potential as a transparent dielectric material, SF-DNA films could potentially form optical elements, such as lenses, prisms, and waveguides, for dual-band, near-IR and THz applications. SF-DNA films were classified according to their thickness.
View Article and Find Full Text PDFA multi-wavelength mode-locked fiber laser can generate different wavelengths from a single laser cavity, offering potential as a dual-frequency comb and serving as an ideal light source for terahertz wave generation. We present an optimized hybrid mode-locked Er-doped fiber laser with flexible outputs: switchable and tunable dual-wavelength mode-locking, along with stable tri-wavelength mode-locking, which is achieved by introducing 0.69 m polarization-maintaining fiber and bent 200 m single-mode fiber to enhance intra-cavity birefringence and nonlinear effect to optimize the hybrid mode-locking effect, that is, build the composite filter effect.
View Article and Find Full Text PDFSensors (Basel)
September 2024
RECENDT-Research Center for Non Destructive Testing GmbH, Science Park 2, 2.OG, Altenbergerstrasse 69, 4040 Linz, Austria.
Many non-destructive optical testing methods are currently used for material research, providing various information about material parameters. At RECENDT, a multimodal experimental setup has been designed that combines terahertz (THz) spectroscopy, optical coherence tomography (OCT), infrared (IR), and Raman spectroscopy with a tensile test stage. This setup aims to gather material information such as crystallinity and optical parameters of high-density polyethylene (HDPE) during a tensile test.
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