Sunday, December 27, 2009



FIELD OF THE INVENTION The present invention relates to a sample analysis method based on nuclear magnetic resonance (NMR) spectroscopy. The invention also relates to a corresponding computer program product and device for carrying out the method.


According to a first aspect of the invention there is provided a method of analyzing a sample consisting of molecules, the analysis being based upon nuclear magnetic resonance spectroscopy, the method comprising the following steps:

- turning on a light source;

- introducing orbital angular momentum into the light;

- obtaining a focused light beam carrying orbital angular momentum; sequentially illuminating the sample with the focused light beam carrying orbital angular momentum for obtaining nuclear magnetic polarizability of the sample; and

- obtaining a free induction decay signal resulting from the illumination, the free induction decay signal carrying characteristics of the sample.

This provides clear advantages, namely for instance the obtained free induction decay (FID) signal is much stronger than the corresponding signal obtained by using traditional NMR spectroscopy methods. Thus, the sensitivity of the measurement technique is greatly improved. The obtained FID signal is also less noisy and better resolution can be achieved. As a consequence smaller samples can be analyzed.

According to a second aspect of the invention there is provided a computer program product comprising instructions for implementing the method according the first aspect of the invention when loaded and run on computer means of an analysis device.

Tuesday, December 22, 2009

Superposition of helical beams by using a Michelson interferometer

Superposition of helical beams by using a Michelson interferometer

Chunqing Gao, Xiaoqing Qi, Yidong Liu, and Horst Weber

Monday, December 21, 2009

Orbital Angular Momentum in Radio - A System Study

Orbital Angular Momentum in Radio - A System Study

Mohammadi, S. M. Daldorff, L. K. S. Bergman, J. E. S. Karlsson, R. L. Thide, B. Forozesh, K. Carozzi, T. D. Isham, B.

This paper appears in: Antennas and Propagation, IEEE Transactions on
Accepted for future publication
ISSN: 0018-926X
Recent discoveries concerning rotating (helical) phase fronts and orbital angular momentum (OAM) of laser beams are applied to radio frequencies and comprehensive simulations of a radio OAM system are performed. We find that with the use of vector field-sensing electric and magnetic triaxial antennas, it is possible to unambiguously estimate the OAM in radio beams by local measurements at a single point, assuming ideal (noiseless) conditions and that the beam axis is known. Furthermore, we show that conventional antenna pattern optimization methods can be applied to OAM-generating circular arrays to enhance their directivity.

Index Terms
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Wednesday, March 11, 2009

Quantum Multiplexing with the Orbital Angular Momentum of light

Quantum Multiplexing with the Orbital Angular Momentum of light
Authors: Juan Carlos Garcia-Escartin, Pedro Chamorro-Posada
(Submitted on 29 Jan 2009)

Abstract: The orbital angular momentum, OAM, of photons offers a suitable support to carry the quantum data of multiple users. We present two novel optical setups that send the information of n quantum communication parties through the same free-space optical link. Those qubits can be sent simultaneously and share path, wavelength and polarization without interference, increasing the communication capacity of the system. The first solution, a qubit combiner, merges n channels into the same link, which transmits n independent photons. The second solution, the OAM multiplexer, uses CNOT gates to transfer the information of n optical channels to a single photon. Additional applications of the multiplexer circuits, such as quantum arithmetic, as well as connections to OAM sorting are discussed.

Friday, February 13, 2009

Twisted radio beams could untangle the airwaves

The human race is not only exhausting tangible resources such as oil. The radiofrequency spectrum available for wireless communication is becoming the increasingly crowded, with virgin "veins" of frequency running short.

However, Swedish physicists say that twisting radio beams into a helical shape as they are transmitted could help ease the congestion.

Radio frequency encompasses electromagnetic waves between 3 kilohertz and 300 gigahertz, and as wireless communications technology advances much of that range is being used.

Satellite TV, wireless computer networks and cellphones are among the growing technologies vying for space up to 30 gigahertz, with some technology even beginning to extend beyond 100 gigahertz leaving a dwindling supply of virgin terrain to exploit.

Physicist Thomas Leyser at the Swedish Institute of Space Physics in Uppsala, Sweden, thinks he has a novel solution. Along with an international team of physicists, he has demonstrated that it is possible to put a spin on radio beams during their transmission to produce a twisted beam.

"Twisted laser beams have been researched since the 1990s, but it has only now become possible to create twisted beams at the much lower radio frequencies," he says.