Generation of programmable near-Fourier-transform-limited pulses of narrow-band laser radiation from the near infrared to the vacuum ultraviolet

2005 ◽  
Vol 76 (10) ◽  
pp. 103103 ◽  
Author(s):  
R. Seiler ◽  
Th. Paul ◽  
M. Andrist ◽  
F. Merkt
Keyword(s):  
Fourier Transform ◽  
Laser Radiation ◽  
Near Infrared ◽  
Vacuum Ultraviolet ◽  
Narrow Band ◽  
Narrow Band Laser

Quantum Dots by QED

2007 ◽  
Vol 31 ◽  
pp. 1-3 ◽  
Author(s):  
Thomas Prevenslik
Keyword(s):  
Laser Radiation ◽  
Quantum Electrodynamics ◽  
Cavity Qed ◽  
Near Infrared ◽  
Vacuum Ultraviolet ◽  
Light Emission ◽  
Surface Enhanced Raman Spectroscopy ◽  
Laser Wavelength ◽  
X Rays ◽  
Specific Heats

High quantum dot (QD) efficiency may be explained by excitons generated in the quantum electrodynamics (QED) confinement of electromagnetic (EM) radiation during the absorption of the laser radiation. There is general agreement that by the Mie theory laser photons are fully absorbed by QDs smaller than the laser wavelength. But how the absorbed laser photons are conserved by a QD is another matter. Classically, absorbed laser radiation is treated as heat that in a body having specific heat is conserved by an increase in temperature. However, the specific heats of QDs vanish at frequencies in the near infrared (NIR) and higher, and therefore an increase in temperature cannot conserve the absorbed laser photons. Instead by QED, the laser photon energy is first suppressed because the photon frequency is lower than the EM confinement frequency imposed by the QD geometry. To conserve the loss of suppressed EM energy, an equivalent gain must occur. But the only EM energy allowed in a QED confinement has a frequency equal to or greater than its EM resonance, and therefore the laser photons are then up-converted to the QD confinement frequency - the process called cavity QED induced EM radiation. High QD efficiency is the consequence of multiple excitons generated in proportion to very high QED induced Planck energy because at the nanoscale the EM confinement frequencies range from the vacuum ultraviolet (VUV) to soft x-rays (SXRs). Extensions of QED induced EM radiation are made to surface enhanced Raman spectroscopy (SERS) and light emission from porous silicon (PS).

Room-Temperature Near-Infrared Metastable Species Measured by Phase-Sensitive Lock-in and Fourier Transform Techniques

1998 ◽  
Vol 45 (4) ◽  
pp. 503-508 ◽  
Author(s):  
Pi-Tai Chou ◽  
Youn-Chan Chen ◽  
Shu-Juan Chen ◽  
Min-Zen Lee ◽  
Ching-Yen Wei ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Room Temperature ◽  
Near Infrared ◽  
Phase Sensitive ◽  
Lock In

Rapid Determination of Heartwood Extractives in Larix sp. by Means of Fourier Transform near Infrared Spectroscopy

2002 ◽  
Vol 10 (3) ◽  
pp. 203-214 ◽  
Author(s):  
N. Gierlinger ◽  
M. Schwanninger ◽  
B. Hinterstoisser ◽  
R. Wimmer
Keyword(s):  
Fourier Transform ◽  
Near Infrared ◽  
Cross Validation ◽  
Nir Spectroscopy ◽  
Solid Wood ◽  
Hot Water ◽  
Extractive Content ◽  
Fast Method ◽  
Wood Powder ◽  
Test Set

The feasibility of Fourier transform near infrared (FT-NIR) spectroscopy to rapidly determine extractive and phenolic content in heartwood of larch trees ( Larix decidua MILL., L. leptolepis (LAMB.) CARR. and the hybrid L. x eurolepis) was investigated. FT-NIR spectra were collected from wood powder and solid wood using a fibre-optic probe. Partial Least Squares (PLS) regression analyses were carried out describing relationships between the data sets of wet laboratory chemical data and the FT-NIR spectra. Besides cross and test set validation the established models were subjected to a further evaluation step by means of additional wood samples with unknown extractive content. Extractive and phenol contents of these additional samples were predicted and outliers detected through Mahalanobis distance calculations. Models based on the whole spectral range and without data pre-processing performed well in cross-validation and test set validation, but failed in the evaluation test, which is based on spectral outlier detection. But selection of data pre-processing methods and manual as well as automatic restriction of wavenumber ranges considerably improved the model predictability. High coefficients of determination ( R2) and low root mean square errors of cross-validation ( RMSECV) were obtained for hot water extractives ( R2 = 0.96, RMSECV = 0.86%, range = 4.9–20.4%), acetone extractives ( R2 = 0.86, RMSECV = 0.32%, range = 0.8–3.6%) and phenolic substances ( R2 = 0.98, RMSECV = 0.21%, range = 0.7–4.9%) from wood powder. The models derived from wood powder spectra were more precise than those obtained from solid wood strips. Overall, NIR spectroscopy has proven to be an easy to facilitate, reliable, accurate and fast method for non-destructive wood extractive determination.

Modulation transfer function testing of FPA using narrow-band laser speckle

2000 ◽  
Author(s):  
Qing Hua ◽  
Wenlong Zheng ◽  
Yuguang Li ◽  
Yinzhong Liang ◽  
Ping'an He ◽  
...  
Keyword(s):  
Transfer Function ◽  
Modulation Transfer Function ◽  
Narrow Band ◽  
Laser Speckle ◽  
Modulation Transfer ◽  
Function Testing ◽  
Narrow Band Laser

Simultaneous Dielectric and Fourier Transform near Infrared Spectroscopy to Monitor a Polyepoxy Curing Process

2006 ◽  
Vol 14 (3) ◽  
pp. 161-166 ◽  
Author(s):  
Alexandra Durand ◽  
Laïla Hassi ◽  
Gilbert Lachenal ◽  
Isabelle Stevenson ◽  
Gérard Seytre ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Curing Process
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