Review
Optics
Brett N. N. Carnio, Oussama Moutanabbir, Abdulhakem Y. Y. Elezzabi
Summary: Continued development in various fields is driving the need for terahertz-wave technologies to be applied in practical situations. The compatibility of waveguides with on-chip fabrication techniques makes them an ideal choice for on-chip terahertz radiation generation. This review examines different types of waveguides and their ability to produce terahertz radiation, providing valuable information for further development in this area.
LASER & PHOTONICS REVIEWS
(2023)
Article
Nanoscience & Nanotechnology
Alvaro Rodriguez Echarri, Joel D. Cox, F. Javier Garcia de Abajo
Summary: This study introduces a scheme for generating entangled photon pairs directly in optical waveguides, without the need for bulky optical elements. The scheme utilizes the nonlinearity of the waveguide material and offers high conversion efficiency, making it suitable for efficient and compact quantum optics devices.
Article
Materials Science, Multidisciplinary
Bong-Rim Shin, In Cheol Yu, Mojca Jazbinsek, Woojin Yoon, Hoseop Yun, Sang-Wook Kim, Dongwook Kim, Fabian Rotermund, O-Pil Kwon
Summary: The use of dichlorinated molecular anions as materials for THz generators is reported, incorporating two different molecular symmetries of dichlorinated molecular anions and a top-level molecular optical nonlinearity cation. The crystals formed with OHQ-34DCS exhibit a strong nonlinear optical response, while those with OHQ-35DCS do not. The introduction of dichlorinated groups in OHQ-34DCS crystals forms strong halogen bonds and hydrogen bonds, suppressing molecular vibrations and resulting in highly efficient THz wave sources.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Keiji Komatsu, Toshiyuki Iwamoto, Haruhiko Ito, Hidetoshi Saitoh
Summary: Ceramic architectures based on chemical vapor deposition (CVD) are used to create unique crystal structures, morphologies, and properties. This study proposed room-temperature THz gas sensing using terahertz time-domain spectroscopy (THz-TDS) with ceramic architectures. The transmission method was used in THz-TDS. Ppm-order THz gas sensing was performed and achieved.
Article
Chemistry, Multidisciplinary
Hyunseung Jung, Lucy L. Hale, Sylvain D. Gennaro, Jayson Briscoe, Prasad P. Iyer, Chloe F. Doiron, C. Thomas Harris, Ting Shan Luk, Sadhvikas J. Addamane, John L. Reno, Igal Brener, Oleg Mitrofanov
Summary: The effect of terahertz (THz) pulse generation has revolutionized broadband coherent spectroscopy and imaging at THz frequencies. However, THz pulses typically lack spatial structure, whereas structured beams are becoming essential for advanced spectroscopy applications. This study develops a nonlinear InAs metasurface consisting of nanoscale optical resonators for simultaneous generation and structuring of THz beams. The control of spatiotemporal structure using nanoscale emitters opens doors for THz beam engineering and advanced spectroscopy and imaging applications.
Article
Chemistry, Physical
Jindong Chen, Xiaotian Jiang, Qingchen Wu, Zheshuai Lin, Min Luo, Ning Ye
Summary: This review summarizes the achievements in infrared nonlinear optical (IR NLO) pnictide crystals, including their crystal structures, key NLO indexes, and the structure-property correlations. The existing issues and prospective development of NLO pnictides are also discussed.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Engineering, Electrical & Electronic
Felicien Appas, Othmane Meskine, Aristide Lemaitre, Martina Morassi, Florent Baboux, Maria Amanti, Sara Ducci
Summary: This paper reviews the recent achievements in emitting nonclassical states of light by spontaneous parametric down conversion on AlGaAs Bragg reflection waveguides. The material platform offers advantages such as mature fabrication technology, room temperature operation, emission in the telecom C-Band, and compliance with electrical injection. These devices demonstrate the ability to generate various quantum states, ranging from biphoton frequency combs to broadband polarization entanglement, enabling potential applications in quantum processing and flexible quantum networks.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Feng Yu, Li-Cheng Wang, Yang Chen, Qi-Dai Chen, Zhen-Nan Tian, Xi-Feng Ren, Hong-Bo Sun
Summary: The study reduced waveguide birefringence using an amplitude-phase double shaping method, resulting in a more circular cross-section and lower birefringence. A polarization-independent quantum interferometer was fabricated based on this ultralow birefringence waveguide, with interference visibilities and standard deviations of 95% and 0.6% respectively.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Biochemistry & Molecular Biology
Pierre Beaujean, Lionel Sanguinet, Vincent Rodriguez, Frederic Castet, Benoit Champagne
Summary: This study employs quantum chemistry methods to describe the variations of second nonlinear optical responses of molecular switches based on benzazolo-oxazolidine (BOX) units. Opening one BOX can enhance beta and set the depolarization ratio to a one-dimensional value. The effects of subsequent BOX openings differ.
Article
Physics, Multidisciplinary
Shunsuke A. Sato, Angel Rubio
Summary: The nonlinear electric conductivity of graphene is investigated under static electric fields for various chemical potential shifts using the quantum master equation approach. It is found that the effective conductivity is initially suppressed as the field strength increases, reflecting the depletion of effective carriers due to large displacement in the Brillouin zone caused by a strong field. However, beyond a certain field strength, the effective conductivity increases, overcoming carrier depletion through the Landau-Zener tunneling process.
NEW JOURNAL OF PHYSICS
(2021)
Article
Optics
Milan Deumer, Steffen Breuer, Robert Kohlhaas, Simon Nellen, Lars Liebermeister, Sebastian Lauck, Martin Schell, Bjoern Globisch
Summary: The study presents photomixers made of iron doped indium gallium arsenide (InGaAs:Fe) as broadband receivers, demonstrating improved frequency response and lower noise levels. Record high values for cw THz spectroscopy were achieved along with increased dynamic range for frequencies above 1 THz. These improvements enable faster and more precise spectroscopy, benefiting industrial non-destructive testing.
Review
Materials Science, Multidisciplinary
Seung-Jun Kim, Bong Joo Kang, Uros Puc, Won Tae Kim, Mojca Jazbinsek, Fabian Rotermund, O-Pil Kwon
Summary: This paper provides an overview of the research progress on organic nonlinear optical crystals in terahertz wave photonics, including their advantages compared to other alternative THz materials, the basic requirements for organic THz generators and detectors, as well as various molecular engineering approaches for organic NLO crystals developed in the last decade. Additionally, it discusses various types of high-power broadband coherent THz sources and their applications in THz nonlinear optics.
ADVANCED OPTICAL MATERIALS
(2021)
Article
Optics
Giacomo Balistreri, Alessandro Tomasino, Junliang Dong, Aycan Yurtsever, Salvatore Stivala, Jose Azana, Roberto Morandotti
Summary: This work discusses the time-domain integration of broadband terahertz pulses using a tapered two-wire waveguide (TTWWG). It demonstrates that input THz pulses are reshaped into their first-order time integral waveform as they propagate toward the subwavelength output gap. The results pave the way for developing a broadband, analog THz time integrator device for high-speed signal processing in THz communication systems.
LASER & PHOTONICS REVIEWS
(2021)
Article
Optics
Shima Rajabali, Ileana-Cristina Benea-Chelmus
Summary: Photonic integrated circuits have played a significant role in the natural sciences, but terahertz technologies have not fully utilized the design and material freedom provided by these circuits. This perspective focuses on the current state-of-the-art, challenges, and prospects of hybrid optical-terahertz photonic chips, particularly in nonlinear waveguides and waveguide-integrated photoconductive devices. The integration and miniaturization of terahertz photonics on a single chip may enable complex functionalities compatible with telecom and fiber technologies.
Article
Nanoscience & Nanotechnology
Payman Rasekh, Akbar Safari, Murat Yildirim, Ravi Bhardwaj, Jean-Michel Menard, Ksenia Dolgaleva, Robert W. Boyd
Summary: Water molecules have numerous rotational transitions in the infrared and terahertz region, impacting the absorption features in the transmission spectrum of atmospheric terahertz measurements. Absorption at resonant positions increases with terahertz intensity, possibly due to stepwise multiphoton transitions in water molecules. The study also sheds light on various water molecule transitions and their nonlinear response to electromagnetic radiation, advancing the development of more precise terahertz technologies.
Article
Materials Science, Multidisciplinary
Jongtaek Kim, Young Choon Park, Jin-Hong Seok, Mojca Jazbinsek, O-Pil Kwon
Summary: This study investigates the effects of solid-state molecular motions on THz generation characteristics in organic nonlinear optical salt crystals. By classifying and separating the molecular vibrations of HMQ-TMS crystals, the influence on the THz spectra is explored, providing essential information for the design of new organic nonlinear optical salt crystals for THz generators and detectors.
ADVANCED OPTICAL MATERIALS
(2021)
Article
Chemistry, Applied
Seung-Jun Kim, In Cheol Yu, Ji-Ah Lee, Won Tae Kim, Mojca Jazbinsek, Woojin Yoon, Hoseop Yun, Fabian Rotermund, O-Pil Kwon
Summary: In this study, new organic benzothiazolium crystals with very large off-diagonal optical nonlinearity were developed. The PMB-TFO and PMB-BTS crystals exhibit state-of-the-art off-diagonal effective hyperpolarizability due to the V-shape and X-shape alignments of PMB chromophores, showing excellent characteristics for second-order nonlinear optical applications.
Article
Materials Science, Multidisciplinary
Jin-Hong Seok, Deokjoong Kim, Won Tae Kim, Seung-Jun Kim, Woojin Yoon, Ga-Eun Yoon, In Cheol Yu, Mojca Jazbinsek, Sang-Wook Kim, Hoseop Yun, Dongwook Kim, Fabian Rotermund, O-Pil Kwon
Summary: The newly designed halogenated organic quinolinium crystals proposed in this work exhibit optimized molecular ordering to maximize optical nonlinearity and high-performance broadband terahertz (THz) wave generation. These crystals show superior diagonal optical nonlinearity compared to state-of-the-art pyridinium-based crystals, attributed to halogen-induced unique interionic interactions and fine-tuning of space-filling characteristics. Additionally, the halogenated crystals demonstrate excellent thermal stability and the ability for bulk crystal growth of few millimeters lateral size with plate-like morphology. This leads to significantly improved THz wave generation characteristics, exceeding the efficiency and bandwidth limits of inorganic benchmark crystals.
ADVANCED OPTICAL MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Jin-Hong Seok, Uros Puc, Seung-Jun Kim, Woojin Yoon, Hoseop Yun, In Cheol Yu, Fabian Rotermund, Dongwook Kim, Mojca Jazbinsek, O-Pil Kwon
Summary: In this study, high-density organic electro-optic crystals were developed to efficiently generate THz waves in a broad range up to 15 THz, providing a more accessible option for ultra-broadband THz applications. The newly developed OHP-TFS crystals show significantly improved performance compared to traditional inorganic-based THz generators, offering potential for high-accuracy optical characterization in a wide THz range.
ADVANCED OPTICAL MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Ga-Eun Yoon, Jin-Hong Seok, Uros Puc, Bong-Rim Shin, Woojin Yoon, Hoseop Yun, Dongwook Kim, In Cheol Yu, Fabian Rotermund, Mojca Jazbinsek, O-Pil Kwon
Summary: This study develops a new organic terahertz generator based on a catechol group, which suppresses phonons and improves performance. Compared to conventional organic crystals, this generator has smaller phonon amplitude and higher crystal density, resulting in the generation of broadband terahertz waves with high efficiency.
Article
Chemistry, Multidisciplinary
Seung-Jun Kim, In Cheol Yu, Dong-Joo Kim, Mojca Jazbinsek, Woojin Yoon, Hoseop Yun, Dongwook Kim, Fabian Rotermund, O-Pil Kwon
Summary: This study reports a new class of nonlinear optical organic crystals with an extremely large first hyperpolarizability. By incorporating a specific hydrogen-bonding synthon and an optimal selection of molecular anion, the crystals exhibit large macroscopic optical nonlinearity. These crystals show excellent performance in terahertz wave generation, with a wide flat-spectral-band and high-generation efficiency.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Seung-Jun Kim, Jin-Hong Seok, In Cheol Yu, Jeong Hyeon Lee, Won Tae Kim, Bong-Rim Shin, Ga-Eun Yoon, Yun-Sang Lee, Jin Chul Kim, Woojin Yoon, Hoseop Yun, Mojca Jazbinsek, Sang Kyu Kwak, Fabian Rotermund, O-Pil Kwon
Summary: This work reports a series of new organic electro-optic salt crystals with unusual orthogonal dipole-coupling assembly that act as dimple-free THz generators. These crystals exhibit a wide THz absorption-free range from 1.5 to 4.0 THz, which is very beneficial for characterizing molecular phonon motions in THz spectroscopy.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Bong-Rim Shin, In Cheol Yu, Uros Puc, Won Tae Kim, Woojin Yoon, Chaeyoon Kim, Hoseop Yun, Dongwook Kim, Mojca Jazbinsek, Fabian Rotermund, O-Pil Kwon
Summary: A design method is reported to develop new organic crystals with large second-order optical nonlinearity. By analyzing the isomorphic tolerance space and introducing various substituents in different positions, 11 highly efficient nonlinear optical salt crystals were successfully developed.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Yun-Sang Lee, Woojin Yoon, Hoseop Yun, Mojca Jazbinsek, In Cheol Yu, Fabian Rotermund, Dongwook Kim, O-Pil Kwon
Summary: In this study, a newly reported organic nonlinear optical salt crystal, MOS-BBS, exhibits perfectly parallel molecular ordering and noncentrosymmetric structure for maximizing the macroscopic second-order optical nonlinearity. It has a large macroscopic optical nonlinearity and high thermal stability.
BULLETIN OF THE KOREAN CHEMICAL SOCIETY
(2022)
Article
Optics
Bong-Rim Shin, Se-In Kim, Dongwook Kim, Mojca Jazbinsek, Woojin Yoon, Hoseop Yun, In Cheol Yu, Fabian Rotermund, O-Pil Kwon
Summary: A new pi-conjugated cationic chromophore based on phenolic N-pyrimidinyl stilbazolium and its non-centrosymmetric crystals are reported in this study. The chromophore exhibits large molecular optical nonlinearity and co-existence in solution, while displaying a macroscopic second-order nonlinear optical response in the crystalline state.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
Uros Puc, Jeong-A Yang, Deokjoong Kim, O-Pil Kwon, Mojca Jazbinsek
Summary: In this study, we demonstrate the generation of broadband terahertz waves based on benzothiazolium crystals with a repetition rate of 100 MHz. Among various benzothiazolium crystals, PMB-4TFS was selected for its significant macroscopic optical nonlinearity, favorable crystal characteristics, and suppressed molecular phonon vibrations. Pumped at the telecommunication wavelength of 1560 nm, the generated THz spectrum covers up to approximately 15 THz, and the THz amplitude for a 0.29 mm thick crystal at normal incidence is more than ten times higher compared to the inorganic standard ZnTe generator crystal with a thickness of 1.0 mm.
OPTICAL MATERIALS EXPRESS
(2023)
Article
Materials Science, Multidisciplinary
Bong-Rim Shin, In Cheol Yu, Mojca Jazbinsek, Woojin Yoon, Hoseop Yun, Sang-Wook Kim, Dongwook Kim, Fabian Rotermund, O-Pil Kwon
Summary: The use of dichlorinated molecular anions as materials for THz generators is reported, incorporating two different molecular symmetries of dichlorinated molecular anions and a top-level molecular optical nonlinearity cation. The crystals formed with OHQ-34DCS exhibit a strong nonlinear optical response, while those with OHQ-35DCS do not. The introduction of dichlorinated groups in OHQ-34DCS crystals forms strong halogen bonds and hydrogen bonds, suppressing molecular vibrations and resulting in highly efficient THz wave sources.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Bong-Rim Shin, In Cheol Yu, Myeong-Hoon Shin, Mojca Jazbinsek, Fabian Rotermund, O-Pil Kwon
Summary: In this study, efficient organic THz wave generators, 2-(4-hydroxystyryl)-1-methylquinolinium 4-bromobenzenesulfonate (OHQ-BBS) single crystals, were reported. The OHQ-BBS crystals exhibit a wide molecular vibrational mode-free range in the THz frequency region with low absorption. By optical rectification, the OHQ-BBS crystals generate extremely broad, dimple-free THz waves and achieve a higher THz electric field compared to the widely used ZnTe inorganic crystal.
Review
Optics
Andreja Abina, Tjasa Korosec, Uros Puc, Mojca Jazbinsek, Aleksander Zidansek
Summary: This review focuses on the application of terahertz (THz) technologies in detecting biomarkers in urine. Urine liquid biopsy is a non-invasive and important diagnostic method that allows the collection of large volumes of samples. The review summarizes the THz spectral responses of metabolic biomarkers in urine from previous studies and discusses different THz methods used for urine analysis. It also presents perspectives for future research in this field.
Article
Materials Science, Multidisciplinary
Seung-Jun Kim, Se-In Kim, Mojca Jazbinsek, Woojin Yoon, Hoseop Yun, Dongwook Kim, In Cheol Yu, Fabian Rotermund, O-Pil Kwon
Summary: A new class of highly efficient nonlinear optical organic salt crystals, based on two electron-withdrawing groups (EWGs), has been reported. The crystals exhibit enhanced microscopic and macroscopic optical nonlinearity, making them promising materials for various nonlinear optical applications.
ADVANCED PHOTONICS RESEARCH
(2022)
