scholarly journals Experimental Results on Two-Photon Physics from LEP

2007 ◽  
pp. 221-233
Author(s):  
Richard Nisius
Keyword(s):  
Experimental Results ◽  
Two Photon

Two-photon laser excitation of 2p5(2P1/2) 3d levels of neon

1989 ◽  
Vol 67 (10) ◽  
pp. 977-979 ◽  
Author(s):  
G. García ◽  
M. Ortiz ◽  
F. Blanco ◽  
J. A. Sánchez ◽  
J. Campos
Keyword(s):  
Laser Excitation ◽  
Experimental Results ◽  
Two Photon ◽  
Photon Excitation ◽  
Two Photon Excitation

A pulsed two-photon excitation of the 2p5(2P1/2) 3d levels of Ne (3d′ levels), from the metastable 3s(3/2)2 state, was made to measure their lifetimes. The experimental results of this work are 20.1 ± 0.3 and 19.6 ± 0.9 ns for the 3d′(3/2)2 and 3d′ (5/2)2 levels, respectively.

The influence of illumination on two-photon absorption of quantum dots

2018 ◽  
Vol 27 (03) ◽  
pp. 1850031
Author(s):  
Zhiqiang Zhou ◽  
Jiawei Cong ◽  
Hongbing Yao ◽  
Yonghong Fu ◽  
Naifei Ren
Keyword(s):  
Quantum Dots ◽  
Ultraviolet Light ◽  
Cross Section ◽  
Optical Limiting ◽  
Experimental Results ◽  
Photon Absorption ◽  
Illumination Time ◽  
Two Photon Absorption ◽  
Two Photon

The influence of illumination with 365[Formula: see text]nm ultraviolet light on two-photon absorption (TPA) of aqueous Co[Formula: see text] doped CdTe (CdTe:Co) quantum dots (QDs) is studied. The results show that with the increase of illumination time, the TPA cross section of the CdTe:Co QDs increases. The experimental results suggest that this enhancement is due to the reduction of surface nonradiative traps which is consistent with the formation of CdS shell on the surface of CdTe:Co QDs. Meanwhile, the results indicate that aqueous CdTe:Co QDs have good optical limiting and optical stabilization performances. This provides a strategy of TPA enhancement by illumination.

Negative Third Order Optical Susceptibilities of Squaraines

1993 ◽  
Vol 328 ◽  
Author(s):  
R. F. Shi ◽  
Q. L. Zhou ◽  
A. F. Garito
Keyword(s):  
Configuration Interaction ◽  
Experimental Results ◽  
Excited Configuration ◽  
Third Order ◽  
Frequency Limit ◽  
Two Photon ◽  
Photon States ◽  
Zero Frequency

ABSTRACTQuantum Many-electron calculations based on Multiple-excited configuration interaction have been implemented on squaraine Molecules. It is found that certain squaraines possess negative third order optical susceptibilities (γ) even in the zero frequency limit. Our calculations agree well with the experimental results obtained by Dirk and co-workers[1] for anilinium squarylium (BSQ) in terms of the sign and Magnitude. High-lying two-photon states in squaraines are found to be always critically important. The sign of γ is found to depend on the electron donating ability of the two side groups in squaraines.

scholarly journals MULTIMODE HONG–OU–MANDEL INTERFEROMETRY

2005 ◽  
Vol 19 (01n02) ◽  
pp. 1-19 ◽  
Author(s):  
S. P. WALBORN ◽  
W. A. T. NOGUEIRA ◽  
A. N. de OLIVEIRA ◽  
S. PÁDUA ◽  
C. H. MONKEN
Keyword(s):  
Quantum Information ◽  
Pump Beam ◽  
Basic Theory ◽  
Experimental Results ◽  
Two Photon ◽  
Photon Pairs ◽  
Transverse Profile ◽  
Parametric Down Conversion ◽  
Pump Signal ◽  
Down Conversion

We review some recent experiments based upon multimode two-photon interference of photon pairs created by spontaneous parametric down-conversion. The new element provided by these experiments is the inclusion of the transverse spatial profiles of the pump, signal and idler fields. We discuss multimode Hong–Ou–Mandel interference, and show that the transverse profile of the pump beam can be manipulated in order to control two-photon interference. We present the basic theory and experimental results as well as several applications to the field of quantum information.

Two-photon volumetric optical disk storage systems experimental results and potentials

2003 ◽  
Author(s):  
Edwin P. Walker ◽  
Yi Zhang ◽  
Alexandr Dvornik ◽  
Peter Rentzepis ◽  
Sadik Esener
Keyword(s):  
Storage Systems ◽  
Optical Disk ◽  
Experimental Results ◽  
Disk Storage ◽  
Two Photon

scholarly journals Laser-induced plasmas in metal vapors

1989 ◽  
Vol 7 (3) ◽  
pp. 545-550 ◽  
Author(s):  
J. T. Bahns ◽  
M. Koch ◽  
W. C. Stwalley
Keyword(s):  
Low Power ◽  
Dye Laser ◽  
Experimental Results ◽  
Resonance Ionization ◽  
Dye Lasers ◽  
High Electron ◽  
Two Photon ◽  
Cw Laser ◽  
Metal Vapors ◽  
Photon Resonance

Strong ionization in metal vapors is known to be very readily produced by a variety of pulsed and CW lasers. Particularly well known is ‘resonance’ ionization by pulsed or CW dye lasers operated at the atomic resonance lines (e.g. Na 3s → 3p). We also have experimental results for two other forms of ionization: ‘quasiresonant’ ionization using a CW dye laser (e.g. at the Na 3p → 4d transitions), and ‘two-photon resonance’ ionization using a pulsed dye laser (e.g. at the Na 3s → 4d two-photon resonances). Both new forms are visually characterized by bright ‘white sparks’ and correspond to reasonably high electron densities of ∼1014−1015 cm3 and low electron temperatures of ∼0·1−0·2 eV. The ‘quasiresonant’ ionization is remarkable in that it occurs even with a very low power 1 mW focused CW laser in 10 torr of Na. A variety of interesting atomic and molecular spectroscopic features have been observed and analyzed.

Diagnostics of Gold Laser Plasmas

1988 ◽  
Vol 102 ◽  
pp. 357-360
Author(s):  
J.C. Gauthier ◽  
J.P. Geindre ◽  
P. Monier ◽  
C. Chenais-Popovics ◽  
N. Tragin ◽  
...  
Keyword(s):  
Experimental Results ◽  
Pure Gold ◽  
Electronic Temperature ◽  
X Ray ◽  
Laser Plasmas ◽  
Collisional Radiative Model ◽  
Radiative Model

AbstractIn order to achieve a nickel-like X ray laser scheme we need a tool to determine the parameters which characterise the high-Z plasma. The aim of this work is to study gold laser plasmas and to compare experimental results to a collisional-radiative model which describes nickel-like ions. The electronic temperature and density are measured by the emission of an aluminium tracer. They are compared to the predictions of the nickel-like model for pure gold. The results show that the density and temperature can be estimated in a pure gold plasma.

Observation of Phase Contrast Images in STEM and CTEM Modes by Using 100 kV Field Emission Electron Gun

1974 ◽  
Vol 32 ◽  
pp. 390-391
Author(s):  
Y. Harada ◽  
T. Goto ◽  
H. Koike ◽  
T. Someya
Keyword(s):  
Field Emission ◽  
Phase Contrast ◽  
Image Formation ◽  
Fresnel Diffraction ◽  
Experimental Results ◽  
Electron Gun ◽  
Scanning Microscopy ◽  
Emission Electron ◽  
Lattice Images

Since phase contrasts of STEM images, that is, Fresnel diffraction fringes or lattice images, manifest themselves in field emission scanning microscopy, the mechanism for image formation in the STEM mode has been investigated and compared with that in CTEM mode, resulting in the theory of reciprocity. It reveals that contrast in STEM images exhibits the same properties as contrast in CTEM images. However, it appears that the validity of the reciprocity theory, especially on the details of phase contrast, has not yet been fully proven by the experiments. In this work, we shall investigate the phase contrast images obtained in both the STEM and CTEM modes of a field emission microscope (100kV), and evaluate the validity of the reciprocity theory by comparing the experimental results.

A new dissociation mode for dislocations in silicon

1978 ◽  
Vol 36 (1) ◽  
pp. 346-347
Author(s):  
A. Ourmazd ◽  
G.R. Booker ◽  
C.J. Humphreys
Keyword(s):  
Detailed Examination ◽  
Experimental Results ◽  
Dislocation Network ◽  
Weak Beam ◽  
Phosphorus Doped

A (111) phosphorus-doped Si specimen, thinned to give a TEM foil of thickness ∼ 150nm, contained a dislocation network lying on the (111) plane. The dislocation lines were along the three <211> directions and their total Burgers vectors,ḇt, were of the type , each dislocation being of edge character. TEM examination under proper weak-beam conditions seemed initially to show the standard contrast behaviour for such dislocations, indicating some dislocation segments were undissociated (contrast A), while other segments were dissociated to give two Shockley partials separated by approximately 6nm (contrast B) . A more detailed examination, however, revealed that some segments exhibited a third and anomalous contrast behaviour (contrast C), interpreted here as being due to a new dissociation not previously reported. Experimental results obtained for a dislocation along [211] with for the six <220> type reflections using (g,5g) weak-beam conditions are summarised in the table below, together with the relevant values.

Two-photon excitation microscopy in cellular biophysics

1995 ◽  
Vol 53 ◽  
pp. 62-63
Author(s):  
David W. Piston ◽  
Brian D. Bennett ◽  
Robert G. Summers
Keyword(s):  
Confocal Microscopy ◽  
Laser Beam ◽  
Duty Cycle ◽  
Excited Electronic State ◽  
Input Power ◽  
Two Photon ◽  
Simultaneous Absorption ◽  
Photon Excitation ◽  
Very High ◽  
Two Photon Excitation

Two-photon excitation microscopy (TPEM) provides attractive advantages over confocal microscopy for three-dimensionally resolved fluorescence imaging and photochemistry. Two-photon excitation arises from the simultaneous absorption of two photons in a single quantitized event whose probability is proportional to the square of the instantaneous intensity. For example, two red photons can cause the transition to an excited electronic state normally reached by absorption in the ultraviolet. In practice, two-photon excitation is made possible by the very high local instantaneous intensity provided by a combination of diffraction-limited focusing of a single laser beam in the microscope and the temporal concentration of 100 femtosecond pulses generated by a mode-locked laser. Resultant peak excitation intensities are 106 times greater than the CW intensities used in confocal microscopy, but the pulse duty cycle of 10-5 maintains the average input power on the order of 10 mW, only slightly greater than the power normally used in confocal microscopy.

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