Abstract
Supercontinuum sources are all-fiber pulsed laser-driven systems that provide high power spectral densities within ultra-broadband spectral ranges. The tailored process of generating broadband, bright, and spectrally flat supercontinua-through a complex interplay of linear and non-linear processes-has been recently pushed further towards longer wavelengths and has evolved enough to enter the field of mid-infrared (mid-IR) spectroscopy. In this work, we review the current state and perspectives of this technology that offers laser-like emission properties and instantaneous broadband spectral coverage comparable to thermal emitters. We aim to go beyond a literature review. Thus, we first discuss the basic principles of supercontinuum sources and then provide an experimental part focusing on the quantification and analysis of intrinsic emission properties such as typical power spectral densities, brightness levels, spectral stability, and beam quality (to the best of the authors' knowledge, the M2 factor for a mid-IR supercontinuum source is characterized for the first time). On this basis, we identify key competitive advantages of these alternative emitters for mid-IR spectroscopy over state-of-the-art technologies such as thermal sources or quantum cascade lasers. The specific features of supercontinuum radiation open up prospects of improving well-established techniques in mid-IR spectroscopy and trigger developments of novel analytical methods and instrumentation. The review concludes with a structured summary of recent advances and applications in various routine mid-IR spectroscopy scenarios that have benefited from the use of supercontinuum sources.
Highlights
Mid-infrared spectroscopy is a lab-standard non-destructive analytical technique that enables qualitative and quantitative chemical analysis of samples in all states of aggregation
This review has set a focus on various practical aspects and prospects of supercontinuum technology that are relevant for mid-IR spectroscopy
Just as progress on the supercontinuum generation in the 1970s was driven by the interests of Raman spectroscopy, we find that current progress is accelerated primarily by interests of IR spectroscopy, only a limited number of groups had hands on this novel type of mid-IR laser source at the time of writing
Summary
Mid-infrared (mid-IR) spectroscopy is a lab-standard non-destructive analytical technique that enables qualitative and quantitative chemical analysis of samples in all states of aggregation. Thereby, tunable small band-gap lead-salt diode lasers covering the entire mid-IR spectral range [8, 9] have been applied for spectroscopic measurements already in the mid-60s These systems have verified the expectations on high-brightness sources in mid-IR spectroscopy [10,11,12]. In contrast to the above-mentioned systems, high brightness mid-IR QCLs have demonstrated particular application advantages due to their robustness, stable operation at room temperatures, compact dimensions and wide spectral tunability (several chips can be united in one emitter to expand the spectral coverage further). Beyond lasers, infrared synchrotron sources are worth mentioning, as they offer high-brightness levels in ultra-broad spectral ranges [26] These sources are superior to conventional thermal emitters in various mid-IR spectroscopic applications [27,28,29]. This work reviews the current maturity state of the mid-IR fiber-based supercontinuum technology beyond these generation-related subjects—in the applied field of mid-IR spectroscopy—and discusses core concepts, principles, particular emission properties as well as prospects and potential application scenarios
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
