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Nonlinear repolarization dynamics in optical fibers: transient
Nonlinear repolarization dynamics in optical fibers: transient

... for the amplification of a given polarization component of a light beam by using the orthogonal component as a pump beam. However the use of such device in telecommunication applications is limited by the intrinsically slow (of the order of seconds and minutes) response time inherent to photorefracti ...
Lab 8: Polarization of Light
Lab 8: Polarization of Light

... of refraction n, which is the same in all directions of (λ/2) plates. A quarter-wave plate is used to conpropagation through the material. Therefore when vert linear polarization to circular polarization and light enters glass, its speed will be the same in all di- vice-versa. Recall from a previous ...
DNA/RNA nucleotides and nucleosides: direct measurement of
DNA/RNA nucleotides and nucleosides: direct measurement of

... 23]. Some of these studies were in¯uenced by multiphoton processes which lead to ionization in the solvent and/or solute. As pointed out elsewhere [24], for accurate results the experiments in the solution phase require careful consideration of the pulse intensities as in many cases ionization of th ...
Slow light in various media: a tutorial
Slow light in various media: a tutorial

... since potential applications of slow light field are so often in fields far from optical physics, there is a need for a basic treatise of the field accessible to the engineering community. At this time, in our view, this demand had not been adequately filled. Of course, there exists a body of solid ...
Absorption Measurements in Microfluidic Devices using Ring-down Spectroscopy
Absorption Measurements in Microfluidic Devices using Ring-down Spectroscopy

... due to its very high sensitivity and fast response. However, since many analytes are not naturally fluorescent, labelling protocols may have to be introduced and thereby increase the complexity of the analysis. Here, we present an alternative method that is based on optical absorption, or more speci ...
Get
Get

... high signal-to-noise ratio (SNR). Consequently, many applications of CW-CRDS were developed based on the CW laser sources [14–18]. In order to improve the scan frequency precision of laser and detection sensitivity, Hodges et al. proposed a frequency stabilized cavity ringdown spectroscopy (FS-CRDS) ...
Molecular-Fluorescence Enhancement via Blue
Molecular-Fluorescence Enhancement via Blue

... absorption and emission peak wavelengths, as shown in Figure 3b. Because of the difference in peak wavelength (ca. 100 nm) between the absorption and emission spectra of MC, the LSPR peak wavelength of AuNRs can be tuned to be separated from the emission band of MC while overlapping with its absorpti ...
Light Measurement Handbook
Light Measurement Handbook

... segment of the UV spectrum. The harmful effect at 270 nm is two times greater than at the 254 and 297 nm mercury lines, and 9000 times greater than at the 365 nm mercury line. The outlying extremes of the bandwidth are important to consider as well. If, for example, you are trying to assess the effe ...
Calculating characteristics of noncollinear phase matching in
Calculating characteristics of noncollinear phase matching in

... of quantum theory.1,2 In addition, the downconverted photons have found applications in the field of metrology, where they can be used to determine the quantum efficiency of photon-counting detectors, and also to determine the spectral radiance of an infrared source. The photon correlations of down- ...
Applied Fiber Optic Measurement for Geohydraulic Engineering
Applied Fiber Optic Measurement for Geohydraulic Engineering

... vibration sensors for hydroelectric monitoring at the Winooski dam at Vermont. They modified photoelastic (or polarization) based fibre optic pressure sensors. Up to 10 sensors were attached onto each separate multimode fibre. The individual sensors were interrogated via optical frequency domain ref ...
Part I : Theory of two
Part I : Theory of two

... The difference between three-valence model and twocenter model: 1. In two-center model, filled deep and shallow traps are coupled only via the density of electrons in CB. 2. In three-valence, there is also an additional coupling due to the relationship of the centers, which is the same element. ...
Wave Refraction in Negative-Index Media: Always Positive
Wave Refraction in Negative-Index Media: Always Positive

... cannot verify this because the data presented in Fig. 3 of Ref. [4] are without an absolute scale. Many other potentially misleading issues, such as material anisotropy, edge diffraction, etc., need to be fully addressed before applying geometrical optics to such NIM prisms. In conclusion, we have s ...
Relations between electron transport rates determined by pulse
Relations between electron transport rates determined by pulse

... flow to O2 via the photosynthetic carbon oxidation (PCO) cycle and/or Mehler-ascorbate-peroxidase reaction. This reaction in the water cycle competes with carbon fixation and confounds measurements of O2 evolution (Genty et al. 1989, 1992; Asada 1999). Extrapolations of PSII to the absolute photosy ...
Total Internal Reflection Spectroscopy for Studying Soft Matter
Total Internal Reflection Spectroscopy for Studying Soft Matter

... on interfacial properties. Spectroscopy of interfaces is key to identifying the chemical nature, conformation and orientation of molecules at an interface, and to quantifying the composition of an interfacial film. The central challenge in interfacial spectroscopy is distinguishing the few molecule ...
Green's function formulation for third-harmonic generation microscopy
Green's function formulation for third-harmonic generation microscopy

... third-harmonic generation (THG) microscopy7–12 for biology and materials science. THG microscopy was demonstrated by Barad et al. in 1997.7 This technique has been applied for imaging transparent objects,7,8 laser-induced breakdown,9 and biological samples.10–12 The advantages of this technique are ...
Fundamental Limits in Confocal Microscopy
Fundamental Limits in Confocal Microscopy

... the illumination over a large number of overlapping sub-volumes that cover the focus plane and that by doing so, one may produce a 2D image, given sufficiently flexible equipment, one could also use the same total sampling (imaging) time to measure a single point at a great many different times, a s ...
Electrochromic Shift of Chlorophyll Absorption in Photosystem I from
Electrochromic Shift of Chlorophyll Absorption in Photosystem I from

... transfer in wild-type PS I range from 10 to 50 ps (Hastings et al., 1994; Brettel and Vos, 1999; Iwaki et al., 1995; Kumazaki et al., 1994; White et al., 1996; Savikhin et al., 2001), whereas the A12 / FX electron transfer occurs with dual ;10 ns and 200–280 ns kinetics (Bock et al., 1989; van der E ...
Get PDF - OSA Publishing
Get PDF - OSA Publishing

... results into an electromagnetically induced grating (EIG) [13, 14], which possesses photonic band gap (PBG) structure as shown in Fig. 1(c). Such EIG has a potential use in all optical switching [15], manipulation of light propagation to create a tunable photonic band gap [16, 17].This research can ...
Optical Properties of Plasmonic Ag/Ni Square Nanostructures
Optical Properties of Plasmonic Ag/Ni Square Nanostructures

... These electron oscillations will spread to other atoms, resulting in resonant collective electron oscillations. These are called plasmons. The oscillating atoms, which can now be seen as dipoles, will in turn re-emit radiation. This might seem like a quite simple system, but there is still a lot we ...
Untitled
Untitled

... energy in the light beam as it passes through the medium. • In absorption the light energy is converted into the internal energy of the medium and in scattering the light energy is radiated in other directions. Note :“The strength of scattering depends on the size of the particle causing the scatter ...
Noncollinear parametric amplification in the near
Noncollinear parametric amplification in the near

... limited to few femtoseconds allow the investigation and the control of fundamental phenomena occurring in matter at their characteristic timescale such as phase transitions [2, 3], energy transfer [4], quasi-particle formation [5, 6], charge carrier relaxations [7] and many other chemical or biologi ...
Raman Scattering in Solids
Raman Scattering in Solids

... those are the mechanism of high-temperature superconductivity where Raman scattering helps to clarify the symmetry of the energy gap and its relation to the normal state carrier dynamics.23 Another area is the investigation of ferromagnetic oxides which are important for the development of spinelect ...
Appendix B 2Spectral Decomposition of Diffracted Light
Appendix B 2Spectral Decomposition of Diffracted Light

... into a range of directions, not just into a single plane wave. Statistically, the effect of the phase term is small since kx is not deterministic as is independent of zp. Furthermore, the phase term becomes less important if spatially incoherent light is used. Equations B7 and B8 assume spatially co ...
Optical fibres solutions
Optical fibres solutions

... Graded index fibres have a graduated refractive index, it is higher in the middle of the fibre and smaller towards the edges. This means that the mode that have the shortest distance to travel (Down the middle of the fibre) travel the slowest. The modes then stay together and the modal dispersion is ...
Evidence for wavelength dependence of the scattering phase
Evidence for wavelength dependence of the scattering phase

... fields and to predict remote-sensing reflectance accurately. Recent results indicate unexpected variability in the degree to which this aim can be achieved.2–5 The variability has been attributed to poor quality control of either the inherent optical property measurements used to constrain the model ...
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Photoacoustic effect

The photoacoustic effect or optoacoustic effect is the formation of sound waves following light absorption in a material sample. In order to obtain this effect the light intensity must vary, either periodically (modulated light) or as a single flash (pulsed light). The photoacoustic effect is quantified by measuring the formed sound (pressure changes) with appropriate detectors, such as microphones or piezoelectric sensors. The time variation of the electric output (current or voltage) from these detectors is the photoacoustic signal. These measurements are useful to determine certain properties of the studied sample. For example, in photoacoustic spectroscopy, the photoacoustic signal is used to obtain the actual absorption of light in either opaque or transparent objects. It is useful for substances in extremely low concentrations, because very strong pulses of light from a laser can be used to increase sensitivity and very narrow wavelengths can be used for specificity. Furthermore, photoacoustic measurements serve as a valuable research tool in the study of the heat evolved in photochemical reactions (see: photochemistry), particularly in the study of photosynthesis.Most generally, electromagnetic radiation of any kind can give rise to a photoacoustic effect. This includes the whole range of electromagnetic frequencies, from gamma radiation and X-rays to microwave and radio. Still, much of the reported research and applications, utilizing the photoacoustic effect, is concerned with the near ultraviolet/visible and infrared spectral regions.
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