High sensitivity background absorption measurements in semiconductors

2015 ◽  
Author(s):  
Nathan Giannini ◽  
Junior R. Silva ◽  
Chengao Wang ◽  
Alexander R. Albrecht ◽  
Seth D. Melgaard ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Background Absorption ◽  
Absorption Measurements

scholarly journals Absolute Absorption Measurements in Optical Coatings by Laser Induced Deflection

Coatings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 473 ◽  
Author(s):  
Simon Bublitz ◽  
Christian Mühlig
Keyword(s):  
High Sensitivity ◽  
Absolute Measurement ◽  
Deposition Process ◽  
Intense Laser ◽  
Optical Coatings ◽  
Absolute Calibration ◽  
Laser Applications ◽  
Experimental Findings ◽  
Thermal Absorption ◽  
Absorption Measurements

Absolute measurement of residual absorption in optical coatings is steadily becoming more important in thin film characterization, in particular with respect to high power laser applications. A summary is given on the current ability of the laser induced deflection (LID) technique to serve sensitive photo-thermal absorption measurements combined with reliable absolute calibration based on an electrical heater approach. To account for different measurement requirements, several concepts have been derived to accordingly adapt the original LID concept. Experimental results are presented for prominent UV and deep UV laser wavelengths, covering a variety of factors that critically can influence the absorption properties in optical coatings e.g., deposition process, defects and impurities, intense laser irradiation and surface/interface engineering. The experimental findings demonstrate that by combining high sensitivity with absolute calibration, photo-thermal absorption measurements are able to be a valuable supplement for the characterization of optical thin films and coatings.

High-sensitivity laser absorption measurements of broadband absorbers in the near-infrared spectral region

2000 ◽  
Vol 39 (27) ◽  
pp. 5006 ◽  
Author(s):  
Kevin L. McNesby ◽  
Richard T. Wainner ◽  
Robert G. Daniel ◽  
Andrzej W. Miziolek ◽  
William M. Jackson ◽  
...  
Keyword(s):  
Spectral Region ◽  
Near Infrared ◽  
High Sensitivity ◽  
Infrared Spectral Region ◽  
Laser Absorption ◽  
Infrared Spectral ◽  
Absorption Measurements

High sensitivity apparatus for low optical absorption measurements

1984 ◽  
Vol 56 (1) ◽  
pp. 6-9 ◽  
Author(s):  
L. C. Nistor ◽  
S. V. Nistor ◽  
V. Teodorescu
Keyword(s):  
Optical Absorption ◽  
High Sensitivity ◽  
Absorption Measurements

scholarly journals Quantum Enhanced Optical Measurements: From Ultra-High Sensitivity in Absorption Measurements to Ghost Microscopy

Proceedings ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 14
Author(s):  
Elena Losero ◽  
Ivano Ruo-Berchera ◽  
Alessio Avella ◽  
Alice Meda ◽  
Marco Genovese
Keyword(s):  
Shot Noise ◽  
Biological Samples ◽  
Optical Measurement ◽  
High Sensitivity ◽  
Optical Measurements ◽  
Imaging Protocols ◽  
Noise Limit ◽  
Physical Quantities ◽  
Absorption Measurements ◽  
Shot Noise Limit

Quantum enhanced optical measurement protocols aim at reducing the uncertainty in the estimation of some physical quantities of a system below the shot-noise limit, classically unavoidable. In particular when small number of photons is used the shot noise can be the main source of uncertainty, in these cases the use of quantum light is of great interest. Note that there are several situations where the number of photons in the probe can not be increased arbitrarily, as when fragile biological samples are under investigation. Two different imaging protocols are discussed in the following.

Radio Measurements of Coronal Magnetic Fields

1994 ◽  
Vol 144 ◽  
pp. 21-28 ◽  
Author(s):  
G. B. Gelfreikh
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Solar Corona ◽  
Active Regions ◽  
High Sensitivity ◽  
Coronal Magnetic Field ◽  
Transverse Magnetic ◽  
Radio Sources ◽  
Radio Waves ◽  
Solar Active Regions

AbstractA review of methods of measuring magnetic fields in the solar corona using spectral-polarization observations at microwaves with high spatial resolution is presented. The methods are based on the theory of thermal bremsstrahlung, thermal cyclotron emission, propagation of radio waves in quasi-transverse magnetic field and Faraday rotation of the plane of polarization. The most explicit program of measurements of magnetic fields in the atmosphere of solar active regions has been carried out using radio observations performed on the large reflector radio telescope of the Russian Academy of Sciences — RATAN-600. This proved possible due to good wavelength coverage, multichannel spectrographs observations and high sensitivity to polarization of the instrument. Besides direct measurements of the strength of the magnetic fields in some cases the peculiar parameters of radio sources, such as very steep spectra and high brightness temperatures provide some information on a very complicated local structure of the coronal magnetic field. Of special interest are the results found from combined RATAN-600 and large antennas of aperture synthesis (VLA and WSRT), the latter giving more detailed information on twodimensional structure of radio sources. The bulk of the data obtained allows us to investigate themagnetospheresof the solar active regions as the space in the solar corona where the structures and physical processes are controlled both by the photospheric/underphotospheric currents and surrounding “quiet” corona.

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