59 results about "Harmonic radiation" patented technology

An optically pumped semiconductor laser includes an active ring-resonator having two or more optically pumped semiconductor (OPS) structures each including a mirror-structure and a multilayer gain-structure. The mirror-structures serve as fold mirrors for the resonator axis. An optically nonlinear crystal may be included in the ring-resonator for generating second-harmonic radiation from fundamental radiation generated in the resonator. Another optically nonlinear crystal may be provided for generating third-harmonic or fourth-harmonic radiation from the second-harmonic radiation. In one example, including a third-harmonic generating crystal, a passive ring-resonator partially coaxial with the active ring-resonator is provided for circulating second-harmonic radiation to provide resonant amplification of the second-harmonic radiation for enhancing third-harmonic conversion. Apparatus for automatically maintaining the passive ring-resonator in a resonant condition for the second-harmonic radiation is disclosed.

Apparatus and methodology are disclosed for providing effective transmission of data to and/or from an electricity meter by providing embedded radio frequency components. An antenna and stripline or microline filter arrangement are provided as embedded components in association with a transmitter or transceiver portion of the electricity meter's metrology circuitry so as to provide control of out of band harmonic radiation and to provide enhanced signal transmission to and/or from the electricity meter, to accomplish automated meter reading communications or similar. The antenna element is configured and mounted such that, once the electricity meter is fully assembled, the meter case itself can be used as part of a radiating element. An overall resulting integrated design can achieve greater economy utilizing printed circuit board approaches with no additional parts, and with less uncontrolled surface radiation because of the otherwise buried or embedded structure.

A harmonic holography (H²) technique and system that combines holography and nonlinear optics that enables holographic recording of 3D images with femtosecond framing time are provided. The H² technique records holograms with second harmonic (SH) signals scattered off specialized nanocrystals that are functionalized to label specific protein or other biomolecules in a living organism. The capability of generating second harmonic radiations is specific to materials with noncentrosymmetric crystalline structures only, and χ⁽²⁾ vanishes for all other types of materials. Therefore, a sharp contrast is formed when particles of noncentrosymmetric structures are dispersed in a medium of other species, pumped at a fundamental frequency, and imaged at the second harmonic frequency. The new scheme described herein provides a sound basis for a new type of contrast microscopy with enormous potential in molecular biomedical imaging.

A traveling wave ring-resonator is configured to deliver CW single-longitudinal-mode radiation having a fundamental wavelength characteristic of an optically pumped gain-element in the resonator. The delivered fundamental-wavelength radiation is the output-radiation of the resonator. An optically nonlinear crystal is located in the resonator and arranged to convert a fraction of fundamental-wavelength radiation into second harmonic radiation. The conversion of this fraction of fundamental-wavelength radiation to second-harmonic radiation minimizes mode-hopping in the output radiation.

A method for generating ultraviolet radiation includes sum-frequency mixing in one optically nonlinear crystal fundamental-wavelength radiation generated by a Pr:YLF gain-element with radiation having a second-harmonic wavelength of fundamental-wavelength radiation generated by a Pr:YLF gain-element. The second-harmonic wavelength is generated in another optically nonlinear crystal. The fundamental-wavelength radiation being mixed and the fundamental wavelength radiation from which the second-harmonic radiation is generated may have the same wavelength or different wavelengths.

Embodiments of the subject invention relate to a method and apparatus for performing measurements using multiphoton or second harmonic generation (SHG) scattered radiation from a sample including a turbid (scattering) medium includes providing a beam of laser pulses from a laser source having high pulse energies and a repetition rate; splitting the beam of laser pulses into two or more partial beams and focussing and overlaying the partial beams on a sample including the turbid medium; and detecting multiphoton and second harmonic radiation scattered from the sample.

The invention disclosed herein relates to fibre lasers with intra-cavity frequency doubling. In one embodiment, the invention is directed to a fibre laser with intra-cavity frequency doubling characterized in that a non-linear crystal of type II phase matching is used to thereby enable operation of the fibre laser without selection of polarisation of the generated fundamental radiation. The non-linear crystal is oriented so as to minimise the walk-off angle of the second harmonic radiation, and a second dichroic mirror together with one of a plurality of focusing elements forms a telescopic reflector that provides for focusing and compensation of the spatial walk-off effect of the non-linear crystal.

The invention discloses a microstrip rectifying antenna. The microstrip rectifying antenna includes a dielectric substrate as well as a receiving antenna and a rectifying circuit printed at two sides of the dielectric substrate; since microstrip lines of a compact microstrip resonant unit are loaded on the receiving antenna so as to perform coupling excitation on an annular groove, harmonic radiation loss of the antenna can be avoided; and the rectifying circuit is of a series-parallel voltage-multiplying circuit structure, so that the rectifying circuit can be small in size and compact in structure and has high conversion efficiency. The microstrip rectifying antenna of the invention can be used for a microwave energy transmission system and a space microwave energy collection system. The microstrip rectifying antenna of the invention can satisfy requirements of systems for plane miniaturization, portability, low cost, easiness in integration and high conversion efficiency.

In harmonic-generating laser apparatus, plane-polarized fundamental radiation of a laser is converted to harmonic radiation by an optically nonlinear crystal. The power of harmonic radiation generated by the apparatus is selectively varied by selectively rotating the plane of polarization of fundamental radiation entering the optically nonlinear crystal.

The invention discloses a microstrip array antenna with a harmonic suppression function. The microstrip array antenna comprises a dielectric substrate and a microstrip antenna array printed on the surface of the dielectric substrate. According to the microstrip array antenna, feeding is carried out through microstrip lines loaded with compact microstrip resonant units, so that the harmonic radiation loss of the antenna can be avoided; and a miniaturization high-isolation power divider is adopted, so that the microstrip array antenna can be small in size and compact in structure. The microstrip array antenna of the invention can be used to a microwave power transmission system. The microstrip array antenna has the advantages of applicability to the plane miniaturization of a system, small size, easiness in integration and high efficiency.

The invention discloses a method and a device for generating a broadband continuously tunable coherent extreme ultraviolet source. The method comprises the following steps of generating a femtosecond laser beam; focusing the laser beam to working gas, wherein the laser beam and the working gas interact under a vacuum environment to generate higher harmonics; adjusting the incident energy of the laser beam or the gas pressure of the working gas so as to change the phase matching conditions of the higher harmonics to cause the red shift or the blue shift of the frequency of the higher harmonics, therefore realizing the continuous tuning of harmonic radiation wavelengths of all orders of the coherent extreme ultraviolet source. The invention also provides a method for realizing the method. By implementing the method and the device disclosed by the invention, the continuous tuning of the harmonic radiation wavelengths of all the orders of the coherent extreme ultraviolet source can be realized.

An illumination source apparatus (500), suitable for use in a metrology apparatus for the characterization of a structure on a substrate, the illumination source apparatus comprising: a high harmonic generation, HHG, medium (502); a pump radiation source (506) operable to emit a beam of pump radiation (508); and adjustable transformation optics (510) configured to adjustably transform the transverse spatial profile of the beam of pump radiation to produce a transformed beam (518) such that relative to the centre axis of the transformed beam, a central region of the transformed beam has substantially zero intensity and an outer region which is radially outwards from the centre axis of the transformed beam has a non-zero intensity, wherein the transformed beam is arranged to excite the HHG medium so as to generate high harmonic radiation (540), wherein the location of said outer region is dependent on an adjustment setting of the adjustable transformation optics.

The invention discloses a converter with a high-frequency and constant current power supply of a neon light, which comprises a leakage transformer and a resonant capacitor, wherein, the resonant capacitor is connected in parallel at two ends of a primary coil of the leakage transformer, distributed capacitance and load capacitance of the primary coil of the leakage transformer are converted into the capacitance at two ends of a primary coil and the total capacitance connected in parallel with the resonant capacitance, a parallel resonance comprises the primary coil of the leakage transformer and the resonant capacitance, and the resonance frequency is: (see the following formula); wherein, f is resonance frequency, L is inductance of the primary coil, and C is capacitance at two ends of the primary coil and total capacitance connected in parallel with the resonant capacitance converted through distributed capacitance and load capacitance of the primary coil of the leakage transformer. The invention outputs sinusoidal wave voltage to drive the neon light tube through parallel resonance, and current of the neon light tube also adopts sinusoidal wave. Therefore, the brightness of the neon light tube is enhanced, the service life of the neon light tube is prolonged, and the radio-frequency electromagnetic interference caused by the higher harmonic radiation is reduced.

An intra-cavity frequency-tripled OPS laser has a laser-resonator including two optically nonlinear crystals arranged for type-I frequency conversion. One of the crystals generates horizontally polarized second-harmonic radiation from vertically plane-polarized fundamental-wavelength radiation circulating in the laser-resonator. A birefringent filter is located between the optically nonlinear crystals. The birefringent filter selects the fundamental-wavelength, establishes the vertical polarization-orientation, and selectively rotates the polarization-orientation of the second-harmonic radiation from horizontal to vertical. The vertically polarized fundamental and second-harmonic radiations are type-I sum-frequency mixed by the other optically nonlinear crystal.