Leland Stanford Junior University

Stephen E Harris

Guang-Yu Yin

Maneesh Jain

Andrew J Merriam

James F Young

Scott J Sharpe

John J Macklin

Hui Xia

Chih-Sung Chuu

Mark H Sher

Improved production of entangled photon pairs (biphotons) via spontaneous parametric down conversion (SPDC) is provided. In one aspect, forward-wave SPDC is performed in a monolithic resonator (resonant for both signal and idler) having a double pass pump geometry to provide a spectrally bright source of biphotons. In another aspect, backward-wave SPDC is performed in a resonator (resonant for both signal and idler) to provide a spectrally bright source of biphotons. For either of these approaches, the biphotons can be made to have polarization entanglement by using quasi phasematching (QPM) with two QPM periods simultaneously.

Ultrabright long biphoton generation with non-linear optical material

A method for producing electromagnetically induced transparency (EIT) in atoms with hyperfine structure. EIT is the phenomenon in which a material (e.g. lead vapor) becomes transparent to a first electromagnetic frequency (a probe beam) when exposed to a second electromagnetic frequency (a coupling beam). In the present invention, the atom has hyperfine split energy levels. In the method of the present invention, the coupling and probe beams are tuned to transitions between the centers of gravity (COGs) of the hyperfine split levels. This allows high transparencies to be achieved in high opacity materials. Also, the present method can produce EIT in isotopically mixed materials. This is because the COGs of hyperfine split levels (in nuclear spin.notident.0 atoms) are generally coincident with nonhyperfine split levels (in nuclear spin=0 atoms). The method of the present invention is directly applicable to nonlinear sum and difference frequency generation.

Method for producing electromagnetically induced transparency in atoms

Efficient nonlinear processes in a nonlinear optical medium are achieved by combining the concept of electromagnetically induced transparency (EIT) and a strongly-driven atomic local oscillator. The present method uses a nonlinear optical medium having elementary entities, such as atoms or molecules, in which a ground state .vertline.1&gt; and a second state .vertline.2&gt; are selected such that the transition between the ground state .vertline.1&gt; and the second state .vertline.2&gt; is a dipole forbidden transition. An upper state .vertline.3&gt; selected from among the energy states .vertline.i&gt; above the ground state .vertline.1&gt; such that a two-photon transition between the ground state .vertline.1&gt; and the second state .vertline.2&gt; via the upper state .vertline.3&gt; is allowed. A strongly-driven coherent superposition state which gives rise to the strongly-driven local oscillator is produced by applying two pumping beams, P1 and P2, at frequencies corresponding to transitions between states .vertline.2&gt; and .vertline.3&gt; and between states .vertline.1&gt; and .vertline.3&gt;. The nonlinear optical medium prepared in this way is used for efficient sum-and-difference and parametric generation in .LAMBDA. and ladder systems.

Method and apparatus for nonlinear frequency generation using a

A traveling-wave, laser-produced-plasma, energy source used to obtain single-pass gain saturation of a photoionization pumped laser. A cylindrical lens is used to focus a pump laser beam to a long line on a target. Grooves are cut in the target to present a surface near normal to the incident beam and to reduce the area, and hence increase the intensity and efficiency, of plasma formation.

Traveling-wave laser-produced-plasma energy source for photoionization

A microwave pumped excimer laser and method.

Microwave excited excimer laser and method

The method of generating XUV radiation which involves exciting atoms to a storage level, irradiating the excited atoms and raising them to a higher level and allowing the atoms to lase to a lower level other than ground which is simultaneously emptied.

XUV Laser and method

A vacuum ultraviolet and x-ray light source based on spontaneous anti-Stokes scattering from atomic population stored in a metastable level is described. The source has a maximum brightness, attained as the media approaches two-photon opacity, equal to that of a blackbody at a Boltzmann temperature characteristic of the population of the metastable level. The source may have high resolution, picosecond time scale, and on a pulsed basis is brighter than other laboratory vacuum ultraviolet light sources. Short wavelength lasers pumped by said source are also described. The lasing atomic species can be separate from or combined in the same envelope with the light source atomic species. Use of the source for spectrographic applications is also described.

Vacuum ultraviolet and x-ray light source and method and short

Isotope separation is achieved between species A and B having an absorption resonance separated by an isotopic shift by selectively exciting a portion of species A using a tunable photon source of narrow emission line with and subsequently causing collisions with an optically excited third species to selectively ionize the excited portion of species A. When ionized, species A is easily separated by any technique, using its ionized condition to distinguish it from species B.

Growing community of inventors

Palo Alto, CA, United States of America

Stephen E Harris