On-Chip Integrated Mid-Infrared GaAs/AlGaAs Mach–Zehnder Interferometer

Sieger, Markus; Balluff, Franz; Kim, Seong-Soo; Leidner, Lothar; Gauglitz, Güenter; Mizaikoff, Boris

doi:10.1021/ac302551s

Cited by 58 publications

(40 citation statements)

References 10 publications

(23 reference statements)

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“…The coherent nature of QCL emission enables advanced measurement schemes beyond conventional direct absorption measurements such as optical heterodyne detection 38,[89][90][91] or Mach-Zehnder interferometry. [92][93][94] Further, an optical coherence tomography (OCT) system in the mid-IR region based on a QCL has been realized. 95,96 The improved characteristics of QCLs enabled the implementation of frequency combs 97 that provide an emission spectrum composed of a set of modes that are perfectly equally-spaced and have a well-defined phase relationship between each other.…”

Section: Specific Properties Of Qcls Relevant For Applied Spectroscopymentioning

confidence: 99%

Quantum cascade lasers (QCLs) in biomedical spectroscopy

2017

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Quantum cascade lasers (QCL) are the first room temperature semiconductor laser source for the mid-IR spectral region, triggering substantial development for the advancement of mid-IR spectroscopy. Mid-IR spectroscopy in general provides rapid, label-free and objective analysis, particularly important in the field of biomedical analysis. Due to their unique properties, QCLs offer new possibilities for development of analytical methods to enable quantification of clinically relevant concentration levels and to support medical diagnostics. Compared to FTIR spectroscopy, novel and elaborated measurement techniques can be implemented that allow miniaturized and portable instrumentation. This review illustrates the characteristics of QCLs with a particular focus on their benefits for biomedical analysis. Recent applications of QCL-based spectroscopy for analysis of a variety of clinically relevant samples including breath, urine, blood, interstitial fluid, and biopsy samples are summarized. Further potential for technical advancements is discussed in combination with future prospects for employment of QCL-based devices in routine and point-of-care diagnostics.

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Section: Specific Properties Of Qcls Relevant For Applied Spectroscopymentioning

confidence: 99%

Quantum cascade lasers (QCLs) in biomedical spectroscopy

2017

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“…This is made possible by employing an interferometric principle of operation in a Mach-Zehnder type optical setup. Although single wavelength (integrated) Mach-Zehnder interferometers (MZI) are widely employed for (bio-)chemical sensing, especially in the visible spectral range [17,18], a report on directly recording a liquid sample's absorption and dispersion spectrum in the Mid-IR using a MZI is, to the best of our knowledge, yet pending. The reader is, however, pointed to infrared spectroscopic ellipsometry [19] and dispersive Fourier transform spectroscopy [20,21,22] that were used in (far-) infrared spectroscopic measurements of the complex dielectric function, mostly in reflection measurements.…”

Section: 29 Page 2 Ofmentioning

confidence: 99%

A quantum cascade laser-based Mach–Zehnder interferometer for chemical sensing employing molecular absorption and dispersion

et al. 2018

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We employ a novel spectroscopic setup based on an external cavity quantum cascade laser and a Mach-Zehnder interferometer to simultaneously record spectra of absorption and dispersion of liquid samples in the mid-infrared. We describe the theory underlying the interferometric measurement and discuss its implications for the experiment. The capability of simultaneously recording a refractive index and absorption spectrum is demonstrated for a sample of acetone in cyclohexane. The recording of absorption spectra is experimentally investigated in more detail to illustrate the method's capabilities as compared to direct absorption spectroscopy. We find that absorption signals are recorded with strongly suppressed background, but with smaller absolute sensitivity. A possibility of optimizing the setup's performance by unbalancing the interferometer is presented.

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“…A photograph of the reader, a diagram of on-chip components, and the results of the biomolecular interaction in case of C-reactive protein is given [319]. An interesting idea is the migration of the Mach-Zehnder chemical sensor and biosensor to the mid-infrared region (MIR) as has been done in the application of the new device for the detection of the herbicide simazine [320,321]. By these means, selectivity information of MIR and sensitivity of Mach-Zehnder can be combined.…”

Section: Dual Pathwaymentioning

confidence: 99%

Critical assessment of relevant methods in the field of biosensors with direct optical detection based on fibers and waveguides using plasmonic, resonance, and interference effects

Gauglitz

2020

Anal Bioanal Chem

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Direct optical detection has proven to be a highly interesting tool in biomolecular interaction analysis to be used in drug discovery, ligand/receptor interactions, environmental analysis, clinical diagnostics, screening of large data volumes in immunology, cancer therapy, or personalized medicine. In this review, the fundamental optical principles and applications are reviewed. Devices are based on concepts such as refractometry, evanescent field, waveguides modes, reflectometry, resonance and/or interference. They are realized in ring resonators; prism couplers; surface plasmon resonance; resonant mirror; Bragg grating; grating couplers; photonic crystals, Mach-Zehnder, Young, Hartman interferometers; backscattering; ellipsometry; or reflectance interferometry. The physical theories of various optical principles have already been reviewed in detail elsewhere and are therefore only cited. This review provides an overall survey on the application of these methods in direct optical biosensing. The "historical" development of the main principles is given to understand the various, and sometimes only slightly modified variations published as "new" methods or the use of a new acronym and commercialization by different companies. Improvement of optics is only one way to increase the quality of biosensors. Additional essential aspects are the surface modification of transducers, immobilization strategies, selection of recognition elements, the influence of non-specific interaction, selectivity, and sensitivity. Furthermore, papers use for reporting minimal amounts of detectable analyte terms such as value of mass, moles, grams, or mol/L which are difficult to compare. Both these essential aspects (i.e., biochemistry and the presentation of LOD values) can be discussed only in brief (but references are provided) in order to prevent the paper from becoming too long. The review will concentrate on a comparison of the optical methods, their application, and the resulting bioanalytical quality.

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On-Chip Integrated Mid-Infrared GaAs/AlGaAs Mach–Zehnder Interferometer

Cited by 58 publications

References 10 publications

Quantum cascade lasers (QCLs) in biomedical spectroscopy

Quantum cascade lasers (QCLs) in biomedical spectroscopy

A quantum cascade laser-based Mach–Zehnder interferometer for chemical sensing employing molecular absorption and dispersion

Critical assessment of relevant methods in the field of biosensors with direct optical detection based on fibers and waveguides using plasmonic, resonance, and interference effects

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