scispace - formally typeset
Search or ask a question
Topic

Absorption (electromagnetic radiation)

About: Absorption (electromagnetic radiation) is a research topic. Over the lifetime, 76674 publications have been published within this topic receiving 1381221 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: The absorption of a single isolated metal cluster is directly measured using a novel far-field optical technique based on modulation of its position using optically detected single gold nanoparticles dispersed on a transparent substrate.
Abstract: The absorption of a single isolated metal cluster is directly measured using a novel far-field optical technique based on modulation of its position. Single gold nanoparticles with average diameters down to 5 nm, dispersed on a transparent substrate, are optically detected and their absolute absorption cross section determined.

285 citations

01 Jan 2013
TL;DR: In this paper, a simple experiment demonstrating that room-temperature thermal transport in Si significantly deviates from the diffusion model already at micron distances is presented, indicating a transition from the diffusive to the ballistic transport regime for the low-frequency part of the phonon spectrum.
Abstract: The "textbook" phonon mean free path of heat carrying phonons in silicon at room temperature is ∼40 nm. However, a large contribution to the thermal conductivity comes from low-frequency phonons with much longer mean free paths. We present a simple experiment demonstrating that room-temperature thermal transport in Si significantly deviates from the diffusion model already at micron distances. Absorption of crossed laser pulses in a freestanding silicon membrane sets up a sinusoidal temperature profile that is monitored via diffraction of a probe laser beam. By changing the period of the thermal grating we vary the heat transport distance within the range ∼1-10 μm. At small distances, we observe a reduction in the effective thermal conductivity indicating a transition from the diffusive to the ballistic transport regime for the low-frequency part of the phonon spectrum.

285 citations

Patent
12 Nov 1998
TL;DR: In this paper, a method and apparatus for measuring an analyte in a tissue of a subject is described, where the temperature probe and the analyte are sufficiently proximate to one another that energy deposited into one by absorption of radiation is transferred to the other.
Abstract: Disclosed is a method and apparatus for measuring an analyte in a tissue of a subject. The method comprises contacting the tissue with electromagnetic radiation having a first excitation wavelength, wherein the first excitation wavelength is substantially equal to an absorption wavelength of a temperature probe within the tissue. The temperature probe and the analyte are sufficiently proximate to one another that energy deposited into one by absorption of radiation is transferred to the other. The Raman spectra emitted by the tissue are collected and analyzed to determine a concentration of analyte present in the tissue. The analysis can comprise measuring the Raman spectra associated with the temperature probe. In addition, the method can include simultaneously contacting the tissue with electromagnetic radiation having the first excitation wavelength and with electromagnetic radiation having a second excitation wavelength, wherein the second excitation wavelength is substantially equal to an absorption wavelength of the analyte. The analysis comprises comparing the spectra emitted in response to the first excitation wavelength in the presence and in the absence of the second excitation wavelength. In another embodiment, the analysis comprises measuring the anti-Stokes component of the Raman spectra associated with the analyte. The method provides a non-invasive measurement of blood glucose, using hemoglobin as the temperature probe.

285 citations

Journal ArticleDOI
TL;DR: A new architecture based on surface plasmon excitation within a metal-insulator-metal device that produces power based on spatial confinement of electron excitation through plAsmon absorption is shown.
Abstract: Conversion of light into direct current is important for applications ranging from energy conversion to photodetection, yet often challenging over broad photon frequencies. Here we show a new architecture based on surface plasmon excitation within a metal–insulator–metal device that produces power based on spatial confinement of electron excitation through plasmon absorption. Plasmons excited in the upper metal are absorbed, creating a high concentration of hot electrons which can inject above or tunnel through the thin insulating barrier, producing current. The theoretical power conversion efficiency enhancement achieved can be almost 40 times larger than that of direct illumination while utilizing a broad spectrum of IR to visible wavelengths. Here we present both theoretical estimates of the power conversion efficiency and experimental device measurements, which show clear rectification and power conversion behavior.

285 citations

Journal ArticleDOI
18 Nov 2004-Nature
TL;DR: It is shown how current directly injected into a freely suspended individual single-wall carbon nanotube can be used to excite, detect and control a specific vibrational mode of the molecule.
Abstract: The interplay between discrete vibrational and electronic degrees of freedom directly influences the chemical and physical properties of molecular systems. This coupling is typically studied through optical methods such as fluorescence, absorption and Raman spectroscopy. Molecular electronic devices provide new opportunities for exploring vibration-electronic interactions at the single molecule level. For example, electrons injected from a scanning tunnelling microscope tip into a metal can excite vibrational excitations of a molecule situated in the gap between tip and metal. Here we show how current directly injected into a freely suspended individual single-wall carbon nanotube can be used to excite, detect and control a specific vibrational mode of the molecule. Electrons tunnelling inelastically into the nanotube cause a non-equilibrium occupation of the radial breathing mode, leading to both stimulated emission and absorption of phonons by successive electron tunnelling events. We exploit this effect to measure a phonon lifetime of the order of 10 ns, corresponding to a quality factor of well over 10,000 for this nanomechanical oscillator.

284 citations


Network Information
Related Topics (5)
Carbon
129.8K papers, 2.7M citations
86% related
Thin film
275.5K papers, 4.5M citations
85% related
Raman spectroscopy
122.6K papers, 2.8M citations
85% related
Graphene
144.5K papers, 4.9M citations
84% related
Silicon
196K papers, 3M citations
84% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2022185
20213,106
20202,866
20192,953
20182,876
20172,679