نتایج جستجو برای: light coherence

تعداد نتایج: 463424  

2009
D. Magatti F. Ferri

We provide an experimental detailed study of the three-dimensional coherence properties of light speckles produced by different tunable pseudothermal sources. Our findings confirm the theoretical prediction of the companion article A. Gatti et al., Phys. Rev. A 78, 063806 2008 , according to which the longitudinal coherence of the speckles is ruled by ordinary diffraction laws only in the deep-...

2008
A. Gatti D. Magatti

We provide a detailed analysis of the three-dimensional spatial coherence properties of light speckles, based on very general assumptions. We show that, while in the deep Fresnel region close to the source the longitudinal coherence of speckles is ruled by the laws of ordinary diffraction, on approach to the Fraunhofer zone the longitudinal coherence length tends to become infinite. We offer bo...

2012
Akihito Ishizaki Graham R. Fleming

Recent two-dimensional (2D) electronic spectroscopic experiments revealed that electronic energy transfer in photosynthetic light harvesting involves long-lived quantum coherence among electronic excitations of pigments. These findings have led to the suggestion that quantum coherence might play a role in achieving the remarkable quantum efficiency of photosynthetic light harvesting. Further, t...

Journal: :Optics letters 2001
G Popescu A Dogariu

We introduce a novel light-scattering technique for investigating the dynamics of random media with a broad range of optical densities. By use of the spatial coherence properties of a single-mode optical fiber and the temporal coherence of a broadband source, the measurement volume is isolated at the end of the optical waveguide. Optical mixing between the fluctuating scattered light and the Fr...

2010
Naohiro Tanno

Optical coherence tomography (OCT) is an optical signal acquisition and processing method. It captures micrometer-resolution, three-dimensional images from within optical scattering media (e.g., biological tissue). Optical coherence tomography is an interferometric technique, typically employing near-infrared light. The use of relatively long wavelength light allows it to penetrate into the sca...

Journal: :Physical review letters 2011
Hirokazu Miyake Georgios A Siviloglou Graciana Puentes David E Pritchard Wolfgang Ketterle David M Weld

We have observed Bragg scattering of photons from quantum degenerate ^{87}Rb atoms in a three-dimensional optical lattice. Bragg scattered light directly probes the microscopic crystal structure and atomic wave function whose position and momentum width is Heisenberg limited. The spatial coherence of the wave function leads to revivals in the Bragg scattered light due to the atomic Talbot effec...

Journal: :Optics letters 1997
A J Devaney A T Friberg A T Kumar E Wolf

It is shown that a highly spatially incoherent light distribution may be generated from a highly coherent one on propagation in free space. This result essentially demonstrates that there exists an inverse of a classic result of optical coherence theory, namely, the van Cittert-Zernike theorem. The analysis also indicates that the technique of phase conjugation may be used to reverse changes in...

Journal: :Nano letters 2015
Shuo Dong Dhara Trivedi Sabyasachi Chakrabortty Takayoshi Kobayashi Yinthai Chan Oleg V Prezhdo Zhi-Heng Loh

Recent observations of excitonic coherences within photosynthetic complexes suggest that quantum coherences could enhance biological light harvesting efficiencies. Here, we employ optical pump-probe spectroscopy with few-femtosecond pulses to observe an excitonic quantum coherence in CdSe nanocrystals, a prototypical artificial light harvesting system. This coherence, which encodes the high-spe...

Journal: :Optics letters 2002
L Vabre A Dubois A C Boccara

We have built a high-resolution optical coherence tomography (OCT) system, based on a Linnik-type interference microscope, illuminated by a white-light thermal lamp. The extremely short coherence length of the illumination source and the large aperture of the objectives permit resolution close to 1 microm in three dimensions. A parallel detection scheme with a CCD camera provides cross-section ...

2017
Kenichi Nakamura Masaru Koshihara Takanori Saitoh Koji Kawakita

[Summary] Optical technologies that have so far been restricted to the field of optical communications are now starting to be applied in new fields, especially medicine. Optical Frequency Domain Reflectometry (OFDR) offering fast and accurate target position measurements is one focus of attention. The Wavelength Swept Light Source (WSLS) is said to be one of the key devices of OFDR, whose sweep...

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