Characterization of aminopyridinium based organic crystals for THz generation

Mandagathingal, Hijas Kalattummal; Li, Shaoxian; Vediyappan, Sivasubramani; Pichan, Karuppasamy; Muthu, Senthil Pandian; Ramasamy, P.; Nugraha, Priyo S.; Polónyi, Gyula; Fülöp, J. A.; Ramamoorthy, Nagalakshmi

doi:10.1016/j.optlastec.2020.106394

Cited by 1 publication

(1 citation statement)

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“…Other anilinetype crystals, including crystals developed in the last decade, are still being investigated to improve the performance of THz wave generation. [152][153][154][155] The THz wave generation performance of another crystal type, i.e., the stilbene-type crystals, is also examined. Among them, stilbazolium-based crystals such as DAST, DSTMS, and their analogous crystals are the most widely investigated at various optical pump wavelengths from near-infrared to infrared.…”

Section: Overview Of Organic Crystals Developed Before 2010mentioning

confidence: 99%

Highly Nonlinear Optical Organic Crystals for Efficient Terahertz Wave Generation, Detection, and Applications

Kim

Kang

Puc

et al. 2021

Advanced Optical Materials

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ordering in the crystalline state should be simultaneously considered when designing organic π-conjugated crystals to achieve the desired physical properties. However, the prediction of the molecular ordering of organic π-conjugated chromophores in the crystalline state is still significantly difficult. This is because most organic π-conjugated chromophores exhibit several complex intermolecular and intramolecular interactions (and interionic interactions) with multiple possible molecular conformations during the self-assembling process in the crystalline state. [17,18] For each specific target application, a different targeted control of the molecular ordering of chromophores in the crystalline state is required, which is still an important issue in the molecular (and crystal) engineering of various organic π-conjugated crystalline materials.This issue is more critical for organic nonlinear optical (NLO) crystals and will be the focus of this review. Organic NLO crystals can be used in diverse nonlinear photonic applications, such as frequency down-and up-conversion, terahertz (THz) wave generation and detection, phase and amplitude electro-optic modulation, and high-speed telecommunication integrated optics. [19][20][21][22][23] Organic crystals must possess a noncentrosymmetric molecular ordering of chromophores to achieve second-order optical nonlinearity. However, in addition to the aforementioned complicated molecular interactions, the introduction of strong polar substituents (electron-donating groups (EDGs) and electron-withdrawing groups (EWGs)) on widely used push-pull π-conjugated chromophores to increase their molecular nonlinearity also increases their dipole moment. In many cases, a high dipole moment leads to a centrosymmetric ordering of chromophores with antiparallel dipole-dipole aggregation in the crystalline state (i.e., there is no macroscopic second-order optical nonlinearity). This tendency further complicates the development of new organic NLO crystals with large second-order optical nonlinearity. This is one of the reasons for only a few classes of organic crystals with state-of-theart optical nonlinearity being reported in the last few decades. Moreover, in addition to large macroscopic second-order optical nonlinearity, different NLO applications require different targeted physical properties (e.g., refractive index, dispersion of the refractive index, dielectric constant, and absorption coefficient) and crystal characteristics (e.g., direction of the polar axis, morphology, aperture size, thickness, and facets). Therefore, it Organic π-conjugated crystals with second-order optical nonlinearity are considerably attractive materials for diverse terahertz (THz) wave photonics. An overview of the research of organic nonlinear optical (NLO) crystals for THz wave generation, detection, and applications is provided here. First, the status of organic NLO crystals compared to other alternative THz materials is described. Second, the basic theory and requirements for organic THz generators and d...

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Section: Overview Of Organic Crystals Developed Before 2010mentioning

confidence: 99%