293 results about "Nonlinear medium" patented technology

The invention provides a laser system (100) wherein the output may be selected from two or more different wavelengths of output laser light. The system (100) comprises a laser capable of having at least two different wavelengths of laser light resonating in the cavity (105) simultaneously. One of the frequencies is generated by a Raman crystal (135) which shifts the frequency of light generated by the lasing medium (125). A tunable non-linear medium (140), such as LBO, is provided in the cavity for selectively frequency converting at least one of the at least two different wavelengths of laser light. The conversion may be SHG, SFG or DFG for example. A tuner (145) is provided to tune the non-linear medium to select the particular wavelength to convert. Temperature tuning or angle tuning of the non-linear medium can be used. A Q switch (130) may also be provided in the cavity. The output laser beam can be used for treatment, detection or diagnosis of a selected area on or in a subject, and can be used in opthalmological and dermatological fields.

A capacitive microfabricated ultrasonic transducer (cMUT) is operated to improve its performance during harmonic imaging in non-linear media, such as in contrast agents or in human tissue. The cMUT is operated by inverting the transmit waveform to adjacently spaced azimuth elements, and combining at least two additional firings without adjacent inversion, for each transmit vector, thereby canceling the second harmonic generation of the cMUT; and thus, the performance of harmonic imaging using the cMUTs can achieve improvement.

Presented is a method of operating a capacitive microfabricated ultrasonic transducer (cMUT) array with multiple firings of varying bias voltage polarity patterns to improve its performance in imaging non-linear media, such as in contrast agent imaging or tissue harmonic imaging. Additionally, transducers incorporating the method are provided. The method of cMUT operation and the corresponding cMUT does not require pre-distortion or phase inversion of the transmit signal and can achieve an improvement in the elevation focus of the cMUT, as compared to the elevation focus that a single firing can achieve. Further, the method of operating the cMUT minimizes the deleterious effects that result from insulators being subjected to high electric fields.

The invention discloses a time pulse width measurement system for ultrashort pulses in different spatial positions and a measurement method thereof. The time pulse width measurement system for ultrashort pulses in different spatial positions comprises an ultrashort pulse light source, a beam splitter, a reflector, an optical delay platform, a nonlinear medium, a slit, a nonlinear sum frequency crystal and a precise detector. The time pulse width measurement system utilizes the pump-detection technology to realize the precise measurement of the ultrashort pulses in a time change process in different spatial positions in the whole airspace in a nonlinear transmission process, thereby simply, conveniently and quickly measuring the time change process of the ultrashort pulses in the differentspatial positions in the whole airspace in transmission, and having high measurement precision.

An optical parametric circuit for separating an input signal light and a wavelength-converted light even when the wavelength difference is small is provided. The optical parametric circuit includes: a nonlinear Mach-Zehnder interferometer which includes a first optical path and a second optical path; optical dispersive mediums and second-order optical nonlinear mediums provided in the first and second optical paths; wherein optical dispersive medium and second-order optical nonlinear medium in the first optical path are placed in the reverse order of optical dispersive medium and second-order optical nonlinear medium in the second optical path.

Systems and methods are provided for ultrafast optical waveform sampling based on temporal stretching of an input signal waveform. Temporal stretching is performed using a time lens based on four-wave mixing in a nonlinear medium. The signal is passed through an input dispersive element. The dispersed signal is sent into the time lens, which comprises a chirped pump pulse and a nonlinear medium. The chirped pump pulse is combined with the signal. The four-wave mixing process occurs in the nonlinear device or medium, which results in the generation of a signal at a new optical frequency (idler). The idler is spectrally separated from the signal and pump pulse using a bandpass filter and sent into an output dispersive element. The output dis persive element is longer than the input dispersive element and the temporal stretching factor is given by the ratio between the dispersions of these two elements.

An optical regenerator for regenerating a multi-level phase encoded signal. A first non-linear medium (HNLF1) generates a comb of frequency harmonics from the signal under the action of a coherent pump, each component bearing the phase encoded data. A filter selects the first and (M−1)th order components. The filtered signal is then input to a second non-linear medium (HNLF2) where a further pump is applied, to coherently add the first and (M−1)th order components and regenerate the signal by reducing phase noise.

The invention relates to a two-dimensional photonic crystal controllable ''AND/OR'' logic gate which comprises four input waveguides and an output waveguide, wherein one input waveguide is used for inputting a control signal; one input waveguide is an idle waveguide; and the other two input waveguides are signal input waveguides. The logic gate is distributed in a mirror symmetry way with a network center axial line of a linear defect waveguide; the symmetrical center position of the intersection of every two input waveguides of the logic gate is provided with a nonlinear dielectric rods as a coupling modulating zone for modulating signal power leading to the next stage of output waveguide; and a nonlinear dielectric rod is arranged on the output waveguide of the logic gate away from the third dielectric rod of the coupling modulating zone. The controllable AND/OR logic gate can be used for logic control of an optical signal by using an all-optical signal, and has the characteristics of small volume, simple structure and high response speed. In addition, all-optical modules of different functions can be manufactured on the same chip so as to be suitable for large-scale optoelectronic integration.

A system and method are presented for generating a localized audible sound field at a designated spatial location. The method comprises: providing sound-data indicative of an audible sound to be produced and location-data indicative of a designated spatial location at which the audible sound is to be produced; and utilizing the sound-data and determining frequency content of at least two ultrasound beams to be transmitted by an acoustic transducer system including an arrangement of a plurality of ultrasound transducer elements for generating said audible sound. The at least two ultrasound beams include at least one primary audio modulated ultrasound beam, whose frequency contents includes at least two ultrasonic frequency components selected to produce the audible sound after undergoing non-linear interaction in a non linear medium, and one or more additional ultrasound beams each including one or more ultrasonic frequency components. The location-data is utilized for determining at least two focal points for the at least two ultrasound beams respectively such that focusing the at least two ultrasound beams on the at least two focal points enables generation of a localized sound field with the audible sound in the vicinity of the designated spatial location.

A system and method for generating an optical comb are provided. The system comprises at least one modulator for modulating a continuous wave sequentially by using at least one signal, respectively so as to generate a comb wave having a first plurality of subcarriers; and a nonlinear medium for causing the respective subcarriers of the comb wave to perform four-wave mixing to thereby generate a comb wave having a second plurality of subcarriers as the optical comb. With the present system and method, an ultra-wide spectrum optical comb with stable frequencies may be generated.

There is provides a wavelength conversion apparatus for converting a wavelength of input signal light and for outputting output signal light of the converted wavelength. The apparatus includes a first and a second nonlinear mediums. The first nonlinear medium receives a first input light and outputs a first output light having a wavelength which is longer than that of the first input light, the wavelength being dependent on optical power of the first input light. The second nonlinear medium receives a second input light and a light output by a light source and outputs a second output light having a wavelength dependent on the wavelengths of the second input light and the light. The first output light is input as the second input light to the second nonlinear medium or the second output light is input as the first input light to the first nonlinear medium.

A method for adaptive streaming of nonlinear video is described wherein the method comprises receiving a manifest file comprising metadata defining a playback period defining video data of a predetermined playback duration, a playback period including at least one adaptation set defining a plurality of representations, each representation defining a set of segment identifiers, each segment identifier identifying a segment comprising a sequence of video frames; the metadata further comprising spatial playback information including at least a first region descriptor associated with a first adaptation set of a first playback period, the first region descriptor defining a destination identifier and a first region in video frames of the first adaptation set, the destination identifier signaling the client apparatus that the first region is linked to a second adaptation set; the client apparatus using the metadata to playback video data of the first adaptation set by requesting one or more network nodes to transmit segments of the first adaptation set; and, receiving or determining, during playback of requested segments, information associated with at least a second region in the video frames of the first adaptation set, the second region defining a region of interest (ROI) of a user of the client apparatus; the client apparatus selecting the second adaptation set for playback after the end of the playback of the first adaptation set on the basis of the first and second region, the selecting being based on a distance or an overlap between the first and second region.

In some aspects of the invention, a method of generating a beam of acoustic energy in a borehole is disclosed. The method includes generating a first broad-band acoustic pulse at a first broad-band frequency range having a first central frequency and a first bandwidth spread; generating a second broad-band acoustic pulse at a second broad-band frequency range different than the first frequency range having a second central frequency and a second bandwidth spread, wherein the first acoustic pulse and second acoustic pulse are generated by at least one transducer arranged on a tool located within the borehole; and transmitting the first and the second broad-band acoustic pulses into an acoustically non-linear medium, wherein the composition of the non-linear medium produces a collimated pulse by a non-linear mixing of the first and second acoustic pulses, wherein the collimated pulse has a frequency equal to the difference in frequencies between the first central frequency and the second central frequency and a bandwidth spread equal to the sum of the first bandwidth spread and the second bandwidth spread.

The invention belongs to the technical field of quantum, and provides a quantum relevancy photon pair source with the adjustable wavelength and the controllable frequency spectrum, and the quantum relevancy photon pair source has the advantages of being small, low in cost and high in purity. According to the technical scheme, a pulse laser with the tunable central wavelength and bandwidth in a wave band ranging from 950 nm to 1150 nm serves as a pumping light; a photonic crystal fiber with specific micro-structure parameters or a micro-nanofiber is selected to serve as a nonlinearity medium, and a quantum relevancy photon pair with the adjustable wavelength and the controllable frequency spectrum is generated by tuning the central wavelength and bandwidth of the pumping light through the spontaneous four-wave mixing process of the nonlinearity medium. The method is mainly applied to quantum technology occasions.

The invention discloses a polarization-unrelated micro ring light switching method and system, and belongs to the field of light communication. The method comprises the steps that firstly, pump light and signal light are input to a nonlinearity medium optical waveguide to generate first conversion light, the wavelength of the pump light is determined according to the wavelength of the first conversion light and the wavelength of the signal light, the polarization state of the pump light is TM or TE, and the polarization state of the first conversion light and the polarization state of the pump light are the same; the pump light and the light with the wavelength being lambda1 and the polarization state being TM or TE are filtered out, the first conversion light and the light with the wavelength being lambda1 and the polarization state being TE or TE are output to a micro ring light switch, and then light switching processing is carried out; the inverse wavelength conversion is carried out, second conversion light with the wavelength being lambda1 and the polarization state being TM or TE is generated and is the same with the signal light in power and phase position; the pump light and the first conversion light are filtered out, and the light with the wavelength being lambda1 and the polarization state being TM and TE is output. The polarization-unrelated micro ring light switching method and system are used for performing light conversion processing, the achievement universality is high, and complexity is low.

According to an aspect of an embodiment, an optical switch comprises:

• • a coupler for coupling a signal light and a control pulse;
  • a first nonlinear medium for amplifying the signal light in accordance with the polarization direction of the control pulse light by nonlinear effect;
  • a first polarizer outputting a component light in a signal light and the control pulse light in parallel with the transmission axis of the first polarizer;
  • a second nonlinear medium for changing status of polarization of the signal light by nonlinear effect; and
  • a second polarizer outputting a signal light and a control pulse light in parallel with the transmission axis of the second polarizer.

A seismic energy source includes at least a first and a second acoustic radiator operatively coupled to a non-linear medium proximate an upper limit of formations in the Earth's subsurface. The first and second acoustic radiators are configured to convert electrical energy directly into acoustic energy. The source includes means for operating the first and the second acoustic radiator at respective first and second frequencies. The first and second frequencies are selected such that substantially no acoustic energy propagates through the non-linear medium. The first and the second frequencies are selected such that a difference therebetween is swept through a range of frequencies of seismic energy capable of propagating through the Earth's subsurface to at least one acoustic impedance boundary within the Earth's subsurface.

The present invention provides a method for designing an optical pulse shaper including a first optical propagation line unit having a nonlinear medium and a dispersion medium concatenated, including: specifying design specifications of the first optical propagation line unit; and based on the design specification, calculating a quasi-periodic stationary pulse of which a waveform of an input optical pulse to the first optical propagation line unit is similar to a waveform of an output pulse from the first optical propagation line unit.

A method and apparatus for nondestructive evaluation (NDE) of structures and materials using a highly nonlinear medium for the generation and detection of one or multiple highly nonlinear pulses (or highly nonlinear waves) impinging on a material or structure. The apparatus includes pulse exciters that induce the propagation of highly nonlinear, weakly nonlinear or linear stress waves in the material, system, or structure to be inspected and/or detectors for the observation and the detection of the output waves from the material/structure being tested. The NDE method includes the use of the tunable highly nonlinear apparatus as impulse exciter alone, or in combination with an accelerometer or a nonlinear sensor to detect the outgoing pulse.

A broadband light source device that can generate supercontinuum light in a visible range and having a spectrum with a stable shape and high intensity is provided. The broadband light source device includes a diode-pumped solid-state laser light source that outputs seed light in response to being excited by a laser beam output from a semiconductor laser light source; a wavelength converter that receives the seed light to generate wavelength-converted light having a wavelength different from that of the seed light, and outputs the wavelength-converted light; and a nonlinear medium that receives the wavelength-converted light to generate supercontinuum light having a bandwidth of 100 nm or greater included in a wave band of 400 nm to 700 nm inclusive, and outputs the supercontinuum light.

A measuring device for femtosecond laser pulse shapes structurally comprises a four-small pore plate, a medium delay piece, a reflector with partial area coated, a paraboloid reflector, a third-order nonlinear medium piece, a small-hole aperture, a focusing lens, a concave reflector and a high resolution spectrograph. And an output end of the high resolution spectrograph is connected with an input end of a computer. The measuring device for femtosecond laser pulse shapes has the advantages of simple and practical structure, convenience for adjusting, quickness in data collection and data processing and suitability for measuring and real-time monitoring of pulse widths and pulse shapes of femtosecond lasers of different pulse widths and wavelengths.

An ultrasonic imaging system transmits waveforms containing first and second major frequency components which are intermodulated by passage through a nonlinear medium or interaction with a contrast agent microbubble to produce a difference frequency component. In an illustrated embodiment the second major frequency is twice the frequency of the first major frequency, resulting in a difference frequency signal at the first major frequency. Two differently modulated transmit waveforms are transmitted and the difference frequency component is separated by pulse inversion.

Phase-matched high-order harmonic generation of soft and hard X-rays is accomplished using infrared driving lasers in a high-pressure non-linear medium. The pressure of the non-linear medium is increased to multi-atmospheres and a mid-IR (or higher) laser device provides the driving pulse. Based on this scaling, also a general method for global optimization of the flux of phase-matched high-order harmonic generation at a desired wavelength is designed.

The invention discloses a method and system for generating quadruplicated frequency optical millimeter waves based on stimulated Brillouin scattering effect. The method comprises the steps that the beat frequency of Stokes light and pump light produced by Brillouin scattering is used as a drive signal of a Mach-Zehnder modulator to modulate output light of a laser device and form a self-starting feedback loop; the amplification effect of Brillouin scattering is utilized to amplify a negative first-order sideband and restrain a positive first-order sideband; the intensity of the Stokes light and corresponding millimeter wave beat frequency are further enhanced, so that modulation depth is increased, and then the amplitude of positive and negative second-order sidebands is enhanced; the optical millimeter waves which are four times of Brillouin frequency shift fB are produced through a wavelength interleaver in a separated mode and output. According to the method, an RF source and a complex control system are not required, and a 4fB optical millimeter wave signal can be produced only through the Mach-Zehnder modulator, the wavelength interleaver, a nonlinear medium segment, a photoelectric detector and an RF amplifier. The method and system for generating the quadruplicated frequency optical millimeter waves have the advantages that stability is high, multiple frequency efficiency is high, and device cost is low.