Organic Crystals for THz Photonics

Organic crystals with second-order optical nonlinearity feature very high and ultra-fast optical nonlinearities and are therefore attractive for various photonics applications. During the last decade, they have been found particularly attractive for terahertz (THz) photonics. This is mainly due to the very intense and ultra-broadband THz-wave generation possible with these crystals. We review recent progress and challenges in the development of organic crystalline materials for THz-wave generation and detection applications. We discuss their structure, intrinsic properties, and advantages compared to inorganic alternatives. The characteristic properties of the most widely employed organic crystals at present, such as DAST, DSTMS, OH1, HMQ-TMS, and BNA are analyzed and compared. We summarize the most important principles for THz-wave generation and detection, as well as organic THz-system configurations based on either difference-frequency generation or optical rectification. In addition, we give state-of-the-art examples of very intense and ultra-broadband THz systems that rely on organic crystals. Finally, we present some recent breakthrough demonstrations in nonlinear THz photonics enabled by very intense organic crystalline THz sources, as well as examples of THz spectroscopy and THz imaging using organic crystals as THz sources for various scientific and technological applications.

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Single Crystals Based on Hydrogen-Bonding Mediated Cation-Anion Assembly with Extremely Large Optical Nonlinearity and Their Application for Intense THz Wave Generation

Advanced Optical Materials ◽

10.1002/adom.201701258 ◽

2018 ◽

Vol 6 (10) ◽

pp. 1701258 ◽

Cited By ~ 11

Author(s):

Seung-Chul Lee ◽

Bong Joo Kang ◽

Ji-Ah Lee ◽

Seung-Heon Lee ◽

Mojca Jazbinšek ◽

...

Keyword(s):

Hydrogen Bonding ◽

Single Crystals ◽

Optical Nonlinearity ◽

Wave Generation ◽

Thz Wave

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Phase-matching condition for THz wave generation via difference frequency generation using InxGa1-xSe mixed crystals

Optics Express ◽

10.1364/oe.393948 ◽

2020 ◽

Vol 28 (14) ◽

pp. 20888

Author(s):

Yohei Sato ◽

Mayu Nakajima ◽

Chao Tang ◽

Katsuya Watanabe ◽

Tadao Tanabe ◽

...

Keyword(s):

Difference Frequency Generation ◽

Matching Condition ◽

Wave Generation ◽

Mixed Crystals ◽

Difference Frequency ◽

Phase Matching ◽

Thz Wave ◽

Frequency Generation ◽

Phase Matching Condition

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Broadband THz Sources from Gases to Liquids

Ultrafast Science ◽

10.34133/2021/9892763 ◽

2021 ◽

Vol 2021 ◽

pp. 1-17

Author(s):

Yiwen E ◽

Liangliang Zhang ◽

Anton Tcypkin ◽

Sergey Kozlov ◽

Cunlin Zhang ◽

...

Keyword(s):

Laser Pulse ◽

Laser Pulses ◽

High Energy ◽

Wave Generation ◽

High Energy Density ◽

Intense Laser ◽

Thz Radiation ◽

Flowing Liquid ◽

Thz Wave ◽

Thz Sources

Matters are generally classified within four states: solid, liquid, gas, and plasma. Three of the four states of matter (solid, gas, and plasma) have been used for THz wave generation with short laser pulse excitation for decades, including the recent vigorous development of THz photonics in gases (air plasma). However, the demonstration of THz generation from liquids was conspicuously absent. It is well known that water, the most common liquid, is a strong absorber in the far infrared range. Therefore, liquid water has historically been sworn off as a source for THz radiation. Recently, broadband THz wave generation from a flowing liquid target has been experimentally demonstrated through laser-induced microplasma. The liquid target as the THz source presents unique properties. Specifically, liquids have the comparable material density to that of solids, meaning that laser pulses over a certain area will interact with three orders more molecules than an equivalent cross-section of gases. In contrast with solid targets, the fluidity of liquid allows every laser pulse to interact with a fresh area on the target, meaning that material damage or degradation is not an issue with the high-repetition rate intense laser pulses. These make liquids very promising candidates for the investigation of high-energy-density plasma, as well as the possibility of being the next generation of THz sources.

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