Journal ArticleDOI
Pulsed optoacoustic spectroscopy of condensed matter
C. K. N. Patel,Andrew C. Tam +1 more
TLDR
In this paper, the authors discuss the theory and experiments dealing with the pulsed optoacoustic effect (i.e., generation of a transient acoustic wave by absorption of an optical pulse) in condensed matter.Abstract:
The authors discuss the theory and experiments dealing with the pulsed optoacoustic effect (i.e., generation of a transient acoustic wave by absorption of an optical pulse) in condensed matter. Their primary interest lies in the measurement of small absorption coefficients (\ensuremath{\ll}${10}^{\ensuremath{-}1}$ ${\mathrm{cm}}^{\ensuremath{-}1}$). At present an experimental capability of measuring absorption coefficients as small as ${10}^{\ensuremath{-}6}$ ${\mathrm{cm}}^{\ensuremath{-}1}$ has been demonstrated, and further improvement is foreseen. The pulsed optoacoustic absorption measurement technique has been applied to the following linear spectroscopic studies: (1) precise measurements of the optical absorption spectra of ${\mathrm{H}}_{2}$O and ${\mathrm{D}}_{2}$O; (b) accurate determination of absorption strengths and profiles of high harmonics ($n=6, 7, \mathrm{and} 8$) of vibrational modes in transparent organic liquids (e.g., benzene); (c) quantitative absorption spectra of thin (\ensuremath{\sim} 1-10 \ensuremath{\mu}m) liquid films; and (d) quantitative absorption spectra of solids and finely powdered crystals. The usefulness of the pulsed optoacoustic technique to nonlinear spectroscopy has been demonstrated in the following studies: (a) quantitative two-photon absorption spectroscopy of the weak two-photon ($^{1}B_{2\ensuremath{\mu}}\ensuremath{\leftarrow}^{1}A_{1g}$) transition in benzene; and (b) optoacoustic Raman-gain spectra for a variety of liquids where an ability to measure Raman gains as small as ${10}^{\ensuremath{-}5}$ ${\mathrm{cm}}^{\ensuremath{-}1}$ has been demonstrated. In addition to reviewing the above studies the authors discuss future possible applications and compare the pulsed optoacoustic spectroscopy technique with other optoacoustic absorption measurement techniques.read more
Citations
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Photoacoustic imaging in biomedicine
Minghua Xu,Lihong V. Wang +1 more
TL;DR: An overview of the rapidly expanding field of photoacoustic imaging for biomedical applications can be found in this article, where a number of imaging techniques, including depth profiling in layered media, scanning tomography with focused ultrasonic transducers, image forming with an acoustic lens, and computed tomography using unfocused transducers are introduced.
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Applications of photoacoustic sensing techniques
TL;DR: In this article, the theory and applications of photo-acoustic (also called optoacoustic) methods belonging to the more general area of photothermal measurement techniques are reviewed, covering excitation of gaseous or condensed samples with modulated continuous light beams or pulsed light beams.
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Surface infrared spectroscopy
TL;DR: The theoretical and experimental foundation of surface IR spectroscopy is described and selected examples are presented to illustrate the kind of information derived in several important areas of surface science such as chemistry, structure, dynamics and kinetics at surfaces as discussed by the authors.
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Characterization of photodamage to Escherichia coli in optical traps.
TL;DR: A wavelength-tunable optical trap was employed in which the microscope objective transmission was fully characterized throughout the near infrared, in conjunction with a sensitive, rotating bacterial cell assay, and the intensity dependence for photodamage was linear, supporting a single-photon process.
Journal ArticleDOI
Detection of thermal waves through optical reflectance
TL;DR: In this article, thermal wave detection and analysis can be performed, in a noncontact and highly sensitive manner, through the dependence of sample optical reflectance on temperature, which is demonstrated by an example of measuring the thickness of thin metal films.