Leland Stanford Junior University

Picarro, Inc.

Other

Anasys Instruments Corporation

Oregon State University

Microtech Instruments, Inc.

Konstantin L Vodopyanov

Chris W Rella

Bruce A Richman

Craig Prater

Robert L Byer

Martin M Fejer

Kevin Kjoller

Michael Reading

A Dazzi Dazzi

Clotilde Policar

Vladimir G Kozlov

Alireza Marandi

Samuel T Wong

Yun-Shik Lee

A random number generator includes a light source emitting light at a first frequency, an optical unit including an optical component configured to receive light at the first frequency and emit light at a second frequency, and a measurement unit configured to receive light at the second frequency, and generate a random output value related to a phase parameter of the light at the second frequency.

Optical quantum random number generator

A coherent light source is provided for producing narrow-linewidth output, continuously tunable within a broad (at least one-octave-wide) range of optical wavelengths. The source is based on type-I or type-0 near-degenerate optical parametric oscillator (OPO), which uses a nonlinear optical crystal with either birefringent phase matching or quasi phase matching. The pump wavelength is chosen such that the OPO degeneracy wavelength (at twice the pump wavelength), is close to the point of zero group-velocity dispersion. That results in an extremely broad OPO bandwidth. Fast OPO wavelength tuning is achieved by rotating an intracavity diffraction grating. In accordance with the invention, the choice of a nonlinear crystal and a pump source determines the overall tuning range. For example, the use of lithium niobate provides tuning over the range of 1.3 to 3 microns, ZGP&#x2014;3.8 to 8 microns, gallium arsenide&#x2014;4 to 12 microns, CGA&#x2014;6 to 13 microns.

Broadly and fast tunable optical parametric oscillator

An AFM based technique has been demonstrated for performing highly localized IR spectroscopy on a sample surface. Significant issues as to size, cost of implementation, and repeatability/robustness of results exist in commercializing the technique. The invention addresses many of these issues thereby producing a version of the analytical technique that can be made generally available to the scientific community.

High frequency deflection measurement of IR absorption

Certain embodiments relate to and involve producing broadband phase-locked frequency combs in the near-infrared and mid-infrared spectral ranges. One such embodiment is directed to a system, with a pump laser and an optical parametric oscillator (OPO) resonator, that is configured to produce broad-bandwidth frequency combs in the near-infrared and mid-infrared frequency ranges. The pump laser is configured to produce femtosecond pulses of light having a pulse repetition rate. The optical parametric oscillator (OPO) resonator that is coupled to the pump laser for facilitating synchronous OPO pumping by matching a roundtrip time of the pulses of light within the OPO resonator with the pulse repetition rate of the pump laser. Among other more specific aspects, the OPO resonator can include a nonlinear optical gain element to provide broad-bandwidth parametric amplification, and optical elements to direct the pulses of light from the femtosecond laser to the nonlinear gain element and to direct subharmonic frequencies of the light out of the optical cavity.

Infrared frequency comb methods, arrangements and applications

Terahertz radiation generation systems and methods are implemented using a variety of methods and devices. According to an example embodiment of the present invention, method for generating terahertz radiation is implemented where the wavelength of an optical pulse is controlled, and where the wavelength is controlled as a function of the group velocity dispersion in a nonlinear crystal. The optical pulse is then directed through consecutively-inverted parallel domains in the nonlinear crystal.

Terahertz radiation generation and methods therefor

A method for generating THz radiation comprises illuminating a semiconductor crystal with an optical pulse train. The semiconductor crystal comprises alternating parallel crystal domains, with each domain having a crystal orientation inverted with respect to adjacent domains. The optical pulse train propagates substantially perpendicularly relative to domain boundaries in the semiconductor crystal. The THz radiation is generated from the optical pulse train by optical down-conversion mediated by the semiconductor crystal. Optical path lengths through the crystal domains at least in part determine a frequency of the generated THz radiation. THz generation efficiency may be enhanced by placing the semiconductor crystal within an external resonant cavity, by placing the semiconductor crystal within a laser cavity, or by placing the semiconductor crystal within an OPO cavity. The semiconductor crystal may comprise zinc-blende, III-V, or II-VI semiconductor.

Generation of terahertz radiation in orientation-patterned semiconductors

A phasor can be employed within the resonator of an optical parametric oscillator (OPO) to adjust the absolute and relative phase of OPO beams. An embodiment of the invention comprises an OPO having at least one phasor for receiving and adjusting the phase of one or more beams resonating within the optical cavity which forms part of the OPO. Smooth alteration of the phases of the OPO beams using the at least one phasor facilitates continuous tuning of the wavelength of at least one of the beams. In another embodiment, the at least one phasor may be a translatable wedge or have adjustable refractive index to alter the phases of the OPO beams. In an additional embodiment, each at least one phasor may be comprised of more than one material, held fixedly together.

Frequency conversion efficiency

Improved multipass second harmonic generation (SHG) is provided by the use of an inverting, self-imaging telescope which ensures parallelism of all passes of all beams within the nonlinear medium. Improved multipass SHG is also provided by the use of a wedged phasor which provides a simple adjustment of the relative phase of the pump beam and second harmonic beam between passes. Improved multipass SHG is provided by the use of an inverting self-imaging telescope in combination with a wedged phasor which provides a simple adjustment of the relative phase of the pump beam and second harmonic beam between passes, ensures parallelism of all passes of all beams within the nonlinear medium. A further embodiment includes an OPO and at least one phasor and preferably first and second telescope assemblies.

According to an embodiment of the invention, improved multipass second harmonic generation (SHG) is provided by the use of an inverting, self-imaging telescope. This embodiment ensures parallelism of all passes of all beams within the nonlinear medium. According to another embodiment of the invention, improved multipass SHG is provided by the use of a wedged phasor. This arrangement provides a simple adjustment of the relative phase of the pump beam and second harmonic beam between passes. According to a further embodiment of the invention, improved multipass SHG is provided by the use of an inverting self-imaging telescope in combination with a wedged phasor. This arrangement provides a simple adjustment of the relative phase of the pump beam and second harmonic beam between passes, and ensures parallelism of all passes of all beams within the nonlinear medium. This arrangement also allows corresponding passes of the pump beam and second harmonic beam to be made collinear within the nonlinear medium by design.

Multipass second harmonic generation

Method and system for providing laser light that is tunable over a relatively wide mid-infrared wavelength range, such as 2-17 &mgr;m. A first noncritically phase matched nonlinear crystal receives a laser light beam and converts the light to a first cavity beam having a first selected wavelength, using optical parametric oscillation techniques. A second noncritically phase matched nonlinear crystal receives the first cavity beam and converts the light to a second cavity beam having a second selected wavelength. Where the first wavelength is tuned (e.g., by temperature change or effective path length change) over a wavelength range of 2-5 &mgr;m, the second wavelength can vary over a higher and broader wavelength range, such as 3-17 &mgr;m.

Cascaded noncritical optical parametric oscillator

Method and system for converting a first light beam having a first frequency into a second light beam having a second frequency. A pump photon having (angular) frequency 3&ohgr; (or 4&ohgr;) is provided within an optical cavity, defined by two mirrors that are fully reflecting at a frequency 2&ohgr;. In a first approach, the pump photon is received and down-converted (3&ohgr;&rarr;2&ohgr;&plus;&ohgr;) by a first nonlinear crystal, and the 2&ohgr; photon is further down-converted (2&ohgr;&rarr;&ohgr;&plus;&ohgr;) by a second nonlinear crystal), to produce three photons (&ohgr;&plus;&ohgr;&plus;&ohgr;) that exit from the cavity. In a second approach, the pump photon is received and down-converted (4&ohgr;&rarr;2&ohgr;&plus;2&ohgr;) by a first nonlinear crystal, and one or both of the 2&ohgr; photons is further down-converted (2&ohgr;&rarr;&ohgr;&plus;&ohgr;) by a second nonlinear crystal).

Laser wavelength tripler with high quantum efficiency

An optical parametric oscillator and a laser system including an optical parametric oscillator is provided for producing widely tunable coherent light over about 6 &mgr;m, such as in the range of at least about 7 &mgr;m to 18 &mgr;m range. Optical parametric oscillators in accordance with the invention advantageously include CdGeAs (CGA) crystals. Such crystals, in accordance with the invention can exhibit exceptionally small (<0.1 cm ) losses in intensity. Laser systems in accordance with the invention can include frequency-doubled CO lasers as the pump beam and frequency doublers or changers, based on CGA crystals.

Growing community of inventors

Stanford, CA, United States of America

Konstantin L Vodopyanov