Highly tunable, high power, efficient terahertz source based on dual-frequency synchronous Thulium-doped fiber laser source

基于双频同步掺铥光纤激光源的高可调、高功率、高效太赫兹源

• 批准号: 283997287
• 负责人: Dr. Matthias Jäger, Ph.D.
• 金额: --
• 依托单位: Leibniz-Institut für Photonische Technologien (IPHT)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/283997287?language=en
• 关键词: Highly; tunable; power; efficient; terahertz; Highly; tunable; power; efficient; terahertz

Terahertz radiation (0.1 - 10 THz) has attracted great interest due to its unique properties, enabling many new applications in the security sector, biology, medicine, and in communications. While THz radiation is weakly absorbed by non-metallic non-polarizing materials, it acts non-ionizing on biological tissue and interacts with many molecules, resulting in readily identifiable absorption peaks. These remarkable properties make THz spectroscopy and multi-spectral imaging very promising and powerful techniques for analyzing substances, materials, devices and products.Even if first commercial systems emerge, large efforts in THz source developments are still required for fully exploiting the properties of THz waves in daily applications. So far, none of numerous THz generation techniques provides a source, which is simultaneously compact, highly efficient (high power), broadly tunable, and works at room temperature. THz sources based on difference frequency generation (DFG) in a nonlinear crystal pumped by diode pumped fiber laser systems are highly attractive since they combine power scalability with the inherent advantages of fiber-integrated setups. However this powerful approach has not been merged yet with frequency tunability essential for THz spectroscopy and multi-spectral imaging applications.This ambitious project aims to tackle this bottleneck by exploiting a novel fiber laser architecture developed by IPHTs and XLIMs expertise in innovative designs for high-power fiber lasers and amplifiers. Using a configurable fiber Bragg grating array with tailored tuning characteristics, the IPHT has recently demonstrated a record tuning bandwidth (74nm in the Yb band) in an electronically tunable nanosecond fiber laser. In a novel resonator design, the IPHT has enhanced this principle towards spectrally independent pulse round trip times enabling a unique dual-frequency operation regime. For the first time, a single fiber-integrated resonator enables a synchronous emission of 2 pulses with tunable emission wavelengths. Together with novel Very Large Mode Area active fibers developed by XLIM, exhibiting unique confinement properties for high power single transverse mode amplifiers while suppressing nonlinear distortions in the system, these techniques enable a pulsed broadly tunable high-power THz source using DFG in a nonlinear crystal.TERATUNE aims to exploit this concept based on a Tm-doped fiber laser and amplifier scheme for developing two classes of high-power THz sources: (i) continuously tunable over the frequency range 0.3 - 1 THz adapted to most THz applications, (ii) discretely tunable covering almost the entire THz regime. The success of this ambitious project demands a high-level of scientific expertise in, photonic technology, specialty laser architecture and novel fibers for ultra-high power optical amplifier systems. These skills come together in the collaboration of IPHT and XLIM with complementary competences.

Terahertz辐射（0.1-10 THZ）由于其独特的特性而引起了极大的兴趣，从而在安全部门，生物学，医学和通信中实现了许多新应用。虽然THZ辐射被非金属非偏振材料弱吸收，但它在生物组织上非离子化并与许多分子相互作用，从而导致易于识别的吸收峰。 这些非凡的特性使THZ光谱和多光谱成像非常有前途和强大的技术来分析物质，材料，设备和产品。到目前为止，众多THZ的生成技术都没有提供一种来源，该来源同时紧凑，高效（高功率），可调性，并且在室温下工作。基于差异频率产生（DFG）的THZ源在由二极管泵浦纤维激光器系统泵送的非线性晶体中非常有吸引力，因为它们将功率可伸缩性与纤维整合设置的固有优势相结合。然而，这种强大的方法尚未与THZ光谱和多光谱成像应用必不可少的频率可调节性合并。这些雄心勃勃的项目旨在通过利用IPHTS和XLIMS在创新设计中为高功率纤维激光器和Amplifier开发的新型纤维激光体系结构来解决这一瓶颈。 IPHT使用具有量身定制的调谐特性的可配置的纤维Bragg光栅阵列，最近在电子可调的纳米纤维激光器中显示了创纪录的调谐带宽（YB频段为74nm）。在一种新颖的谐振设计中，IPHT增强了这一原理朝着频谱独立的脉动往返时间，实现了独特的双频操作制度。单个纤维集成的谐振器首次实现了2种具有可调发射波长的脉冲的同步发射。连同Xlim开发的新型非常大模式区域的活性纤维，在抑制系统中的非线性扭曲的同时，展示了高功率单横向模式放大器的独特限制特性，这些技术可以实现非线性晶体中使用DFG的脉冲可调的高功率THZ源，以开发基于两种概念的DFG。高功率THZ来源：（i）在适应大多数THZ应用程序的0.3-1 THz的频率范围内连续调谐，（ii）可离散可调的覆盖几乎整个THZ款。这个雄心勃勃的项目的成功要求在超高功率光学放大器系统方面具有高级的科学专业知识，光子技术，专业激光体系结构和新型纤维。这些技能在IPHT和XLIM具有互补能力的合作中融合在一起。