Terahertz reflection spectroscopy of Debye relaxation in polar liquids [Invited]

Møller, Uffe; Cooke, David G.; Tanaka, Kōichiro; Jepsen, Peter Uhd

doi:10.1364/josab.26.00a113

Cited by 144 publications

(89 citation statements)

References 42 publications

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“…8 show the distinct differences between their complex dielectric function parameters in the THz regime. Furthermore, the results are comparable to those acquired in literature by reflection [18][19][20] and transmission arrangements 7 showing the validity of the device and the data extraction techniques.…”

Section: A Primary Alcoholssupporting

confidence: 78%

“…17 To allow for greater examination of our results, a further set of experiments was carried out using the same techniques, for an ethanol/water series. For a direct comparison to both work undertaken by reflection spectroscopy techniques [18][19][20] and transmission arrangements, 7 the real and imaginary parts of the complex dielectric function were plotted as a function of frequency ͑Fig. 8͒.…”

Section: A Primary Alcoholsmentioning

confidence: 99%

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Silicon based microfluidic cell for terahertz frequencies

Baragwanath

Swift

Dai

et al. 2010

Journal of Applied Physics

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We present a detailed analysis of the design, fabrication and testing of a silicon based, microfluidic cell, for transmission terahertz time-domain spectroscopy. The sensitivity of the device is tested through a range of experiments involving primary alcohol/water mixtures. The dielectric properties of these solutions are subsequently extracted using a Nelder–Mead search algorithm, and are in good agreement with literature values obtained via alternative techniques. Quantities in the order of 2 μmol can be easily distinguished for primary alcohols in solution, even with the subwavelength optical path lengths used. A further display of the device sensitivity is shown through the analysis of commercial whiskeys, where there are clear, detectable differences between samples. Slight absorption variations were identified between samples of the same commercial brand, owing to a 2.5% difference in their alcoholic content. Results from data taken on subsequent days after system realignment are also presented, confirming the robustness of the technique, and the data extraction algorithm used. One final experiment, showing the possible use of this device to analyze aqueous biological samples is detailed; where biotin, a molecule known for its specific terahertz absorptions, is analyzed in solution. The device sensitivity is once again displayed, where quantities of 3 nmol can be clearly detected between samples.

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Section: A Primary Alcoholssupporting

confidence: 78%

Section: A Primary Alcoholsmentioning

confidence: 99%

Silicon based microfluidic cell for terahertz frequencies

Baragwanath

Swift

Dai

et al. 2010

Journal of Applied Physics

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“…62,[73][74][75] Moller et al provided a good review of this field. 76 In addition, microfluidic devices for liquid spectroscopy have also been demonstrated. 77 As soon as other molecules, such as carbohydrates or proteins, are dissolved in water, it is possible to distinguish between different populations of water molecules based on the change in the relaxational dynamics because the water molecules that are part of the solvation shell exhibit a significantly different dynamics than the bulk water molecules.…”

Section: Mesoscopic Structure and Dynamicsmentioning

confidence: 99%

Terahertz Time-Domain and Low-Frequency Raman Spectroscopy of Organic Materials

2015

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With the ongoing proliferation of terahertz time-domain instrumentation from semiconductor physics into applied spectroscopy over the past decade, measurements at terahertz frequencies (1 THz [ 10 12 Hz [ 33 cm À1) have attracted a sustained growing interest, in particular the investigation of hydrogen-bonding interactions in organic materials. More recently, the availability of Raman spectrometers that are readily able to measure in the equivalent spectral region very close to the elastic scattering background has also grown significantly. This development has led to renewed efforts in performing spectroscopy at the interface between dielectric relaxation phenomena and vibrational spectroscopy. In this review, we briefly outline the underlying technology, the physical phenomena governing the light-matter interaction at terahertz frequencies, recent examples of spectroscopic studies, and the current state of the art in assigning spectral features to vibrational modes based on computational techniques.

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“…One of the biggest barriers to apply THz spectroscopy to biological samples is the strong absorption coefficient of polar liquids in the THz frequencies, typically 250 cm -1 for distilled water (310 K) at 1.0 THz [28]. This can, however, be overcome when THz TD-ATR spectroscopy [29] is used, and the system optimized to accurately measure the target absorptive sample [30].…”

Section: Principlementioning

confidence: 99%

Characterization of Dielectric Responses of Human Cancer Cells in the Terahertz Region

Shiraga

Ogawa

Suzuki

et al. 2014

J Infrared Milli Terahz Waves

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Terahertz time-domain attenuated total reflection spectroscopy, in combination with a two-interface model, is used to determine the complex dielectric constants of cultured human cancer cells (DLD-1, HEK293 and HeLa). Picosecond and sub-picosecond water dynamics are dominant in the measured complex dielectric constants of these cells. We demonstrate that dielectric responses below 1.0 THz best characterize the particular water dynamics of cancer cells when compared with extracellular water. Debye-Lorentz fitting revealed that this is due to a significantly attenuated slow relaxation mode and enhanced fast relaxation mode of the water in these cancer cells. These findings could lead to a new procedure to digitally evaluate cellular activities or functions, in terms of intracellular water dynamics, and remove the veil from the mysterious intracellular milieu.

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Terahertz reflection spectroscopy of Debye relaxation in polar liquids [Invited]

Cited by 144 publications

References 42 publications

Silicon based microfluidic cell for terahertz frequencies

Silicon based microfluidic cell for terahertz frequencies

Terahertz Time-Domain and Low-Frequency Raman Spectroscopy of Organic Materials

Characterization of Dielectric Responses of Human Cancer Cells in the Terahertz Region

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