Electro optic dual comb spectroscopy for mid-infrared applications

ELECTROCOMB项目旨在在中红外光谱区产生波长灵活的频率梳，作为分子光谱和分析的双梳光谱（DCS）的强大工具。频率梳，特别是用于光谱应用的双梳方案目前正经历着强劲的发展。为了满足光谱学和分析应用在波长区域、光谱覆盖范围、测量速度和灵敏度方面的具体需要，正在开发新的梳状产生方案。ELECTROCOMB项目建立在连续波（cw）激光的电光调制（EOM）产生梳的概念之上，该概念是专门为双梳应用而开发的。从同一个主连续波激光器产生两个梳子有助于大大减少两个梳子相互同步所需的努力。此外，它允许根据要分析的光谱特征的宽度调整重复率（梳线间距）。另一方面，与其他源相比，该方案目前在频谱梳宽方面效率较低，并且由于技术原因，该概念仅限于电信范围，主要在1.5 μm左右。ELECTROCOB旨在克服这些障碍。该项目将提高对基于电光梳的基本理解，以增加频谱展宽并将噪声水平降低到接近基本极限。这将与使用chi(2)和chi(3)工艺将非线性光学频率转换到中红外（3 - 5 μm）范围的新颖有效方法相结合。这将使我们能够将这种类型的DCS用于痕量气体分析中的具有挑战性的应用，这些应用需要高灵敏度和广谱覆盖。该项目联盟结合了ICB实验室（勃艮第大学）在光纤非线性过程和梳子生成集成波导方面的互补专业知识，以及IMTEK小组（弗莱堡大学）在通过二次非线性、数据采集和气体分析进行频率转换方面的互补专业知识，以便在梳子生成的基本理解及其在气体光谱中的有效应用方面达到一个新的水平。此外，该联合项目将使合作伙伴获得各自合作伙伴实验室中高度专业化的设备，这将大大提高研究工作的效率。因此，我们期望我们的联合ELECTROCOMB项目将对致力于频谱应用和使用频率梳源的学术界和工业界产生强大的影响。这将通过在国际领先期刊上发表我们的研究成果并在著名的国际会议上发表报告来实现。

The ELECTROCOMB project aims at the generation of wavelength flexible frequency combs in the mid-infrared spectral region as a powerful tool for dual-comb spectroscopy (DCS) for molecular spectroscopy and analytics. Frequency combs and in particular dualcomb schemes for spectroscopic applications are currently experiencing a strong development. Novel comb generation schemes are being developed in order to address the specific needs of spectroscopic and analytical applications in terms of wavelength region, spectral coverage, speed and sensitivity of the measurement. The ELECTROCOMB project builds upon the concept of comb generation with electrooptic modulation (EOM) of a continuous-wave (cw) laser, which has been specifically developed with dual-comb applications in mind. Generating two combs from the same primary cw laser helps to drastically reduce the effort needed for the mutual synchronization of the two combs. In addition, it allows one to adjust the repetition rate (comb line spacing) according to the widths of the spectral features to be analyzed. On the other hand, the scheme is currently less efficient in terms of spectral comb width compared to other sources, and the concept is limited to the telecom ranges, mainly around 1.5 μm for technical reasons. ELECTROCOB aims at overcoming these handicaps. The project will improve the fundamental understanding of the electro-optic based comb in order to increase the spectral broadening and to reduce the noise level closer to the fundamental limits. This will be combined with novel and efficient approaches for the nonlinear-optical frequency conversion into the mid-infrared (mid-IR) range (3 – 5 μm) using both chi(2) and chi(3) processes. This will allow us to use this type of DCS for challenging applications in trace gas analysis which do require both high sensitivity and broad spectral coverage. The project consortium combines the complementary expertise of the ICB laboratory (Université de Bourgogne) on nonlinear processes in fibers and integrated waveguides for comb generation and of the IMTEK group (Freiburg University) on the frequency conversion via quadratic nonlinearities, data acquisition and gas analysis in order to reach a new level in fundamental understanding of comb generation and its efficient application in gas spectroscopy. In addition, the joint project will grant the partners access to highly specialized equipment in the labs of the respective partners which will greatly enhance the efficiency of the research work. As a consequence, we are expecting that our joint ELECTROCOMB project will have a strong impact on the academic and industrial communities working on and using frequency comb sources for spectroscopic applications. This will be achieved through the publication of our results in leading international journals and presentations in prestigious international conferences.