32 results about "Acoustic Phonons" patented technology

A metallic nano-particle surrounded by an amplifying medium results in a boundary condition that creates a singularity in the particle's dynamic polarizability at the localized surface plasmon resonance and at a critical value of the gain is disclosed. The boundary condition may be time dependent due to excitation by a sub-picosecond laser pulse and couples to the electromagnetic vacuum resulting in photon emission in an analogue of the Unruh Effect. The vacuum emission from 2-D nanostructures embedded in high gain laser dyes predicts energies nearly two orders of magnitude larger than the spontaneous emission background. The vacuum radiation is may have a unique dependence on the excitation.

A method for non-invasively probing at least one physics property of a solid material. In one embodiment, the method has the steps of splitting a photon beam into a first photon beam and a second photon beam, exposing the solid material to the first photon beam to generate a coherent acoustic phonon wave in the solid material at time t, and exposing the solid material to the second photon beam at a time t+Δt, where t+Δt≧t, to generate corresponding second harmonic generation signals, where from the corresponding second harmonic generation signals, the at least one physics property of the solid material is determinable.

Methods for synthesizing fibers having nanoparticles therein are provided, as well as preforms and fibers incorporating nanoparticles. The nanoparticles may include one or more rare earth ions selected based on fluorescence at eye-safer wavelengths, surrounded by a low-phonon energy host. Nanoparticles that are not doped with rare earth ions may also be included as a co-dopant to help increase solubility of nanoparticles doped with rare earth ions in the silica matrix. The nanoparticles may be incorporated into a preform, which is then drawn to form fiber. The fibers may beneficially be incorporated into lasers and amplifiers that operate at eye safer wavelengths. Lasers and amplifiers incorporating the fibers may also beneficially exhibit reduced Stimulated Brillouin Scattering.

A sound energy collector by adopting a phonon crystal and an electromechanical Helmholtz resonator, which comprises an electromechanical Helmholtz resonator, a phonon crystal resonant cavity (1), a support column (4) and a base (5), wherein the electromechanical Helmholtz resonator comprises a composite piezoelectric transducer (3) and a Helmholtz resonant cavity (2); the electromechanical Helmholtz resonator is located in the middle position of the phonon crystal resonant cavity and the electromechanical Helmholtz resonator is fixed on the base through the support column; and a phonon crystal resonant cavity body is fixed on the base through bonding. After incident sound waves sequentially go through the gather amplification effects of the phonon crystal resonant cavity and the Helmholtz resonant cavity, the composite piezoelectric transducer is driven to vibrate, so the composite piezoelectric transducer is deformed to transmit electric signals for realizing sound-mechanism-electricity conversion; and the sound energy collector can be applied to sound energy collectors with the characteristics of multi-directions and lower energy density under complex environment, thereby providing electricity for various wireless sensors and micro electro mechanical systems.

The invention provides a method for obtaining time domain flat top beams by using one-time stimulated brillouin scattering light limiting, which relates to the field of nonlinear optics. The method solves the problems that the prior non-linear limiting mechanism can not be applied to protection of a high-power laser system, the device used in the prior method for obtaining flat top beams is complicated, and large output energy from the stimulated brillouin scattering light limiting is lost. The method provided by the invention is that s polarized pump light is input to the system; the light is transmitted to a lens (5) after passing through a 1/2 wave plate (2), a Polaroid (3), and a 1/4 wave plate (4); the light is focused on an oscillating pond (6), and shows the stimulated brillouin scattering effect with a brillouin medium in the oscillating pond (6); the transmitted light resulting from the scattering effect is the time domain flat top beam output from the system; and the phonon lifetime of the brillouin medium ranges from 0ns to 0.3ns. The method for obtaining time domain flat top beams by using one-time stimulated brillouin scattering light limiting has the advantages of simple devices used, wide application scope of wavelengths, high efficiency, etc.

The invention belongs to the field of acoustic functional devices, and discloses an acoustic wave resonator adopting multiple layers of coupled phononic crystals. The acoustic wave resonator is formed by a plurality of two-dimensional phononic crystals with different scattering body sizes and different crystal lattice coefficients in a nested manner. From the inside out, the first layer of phononic crystals is formed by a 3*3 scattering body array with the center being a single-point vacancy defect, the second layer of phononic crystals is formed by a 2*2 scattering body array, the third layer of phononic crystals is formed by a 3*3 scattering body array with the center being a single-point vacancy defect, and the fourth layer of phononic crystals is formed by a 5*5 scattering body array with the center being a multi-point vacancy defect. The acoustic wave resonator can realize efficient detection and capture for weak acoustic waves; compared with a single phononic crystal with the same volume, the multiple layers of coupled phononic crystals have a stronger acoustic wave localization effect and a higher acoustic pressure amplification factor.

In a method for generating a terahertz electromagnetic wave by using coherent phonons in a quantum structure, high density of coherent phonons acting as a radiation source of the terahertz electromagnetic wave are obtained by exciting the inter-band transitions in a quantum structure under the condition that the energy difference between two inter-band transitions in the quantum structure is resonated with the energy of the coherent phonons, and the terahertz electromagnetic wave is generated by the oscillatory polarizations of the coherent phonons. High density of coherent phonons may be created through the elementary excitation generated by using instantaneous laser pulses. A quantum well structure is effective as the quantum structure, and a scattering process of coherent phonon may be suppressed by confining coherent LO phonons in a well layer. Under the condition that the difference of energies between the heavy-hole and light-hole exitons in a quantum well structure agrees with the energy of LO phonons and both the exitons are created simultaneously, high density of coherent phonons may be generated. With this method, a terahertz electromagnetic wave can be effectively and strongly emitted from the coherent phonons.

The invention discloses an ytterbium-erbium doping gadolinium silicate crystal and preparing method, which is characterized by the following: the laser single-crystal structure formula is Ybx, Ery:Gd2SiO5, wherein x is 0.01-0.5; y is 0.001-0.15; the crystal adopts flux method growth; the Yb,Er:Gd2SiO5 crystal possesses high-sound acoustic phonon energy (1000cm-1) with large crystal field splitting, 0.86*10-20cm-1 transmitting cross-section of 1.55 mum band and 7ms fluorescent lifetime, which improves Er3+ luminous efficiency.

An optical amplifier of the present invention includes a pump source for generating a pumping light, a wavelength division multiplexing (WDM) coupler for multiplexing an inputted optical signal and the pumping light and an optical fiber including a core and a clad, wherein the core has holmium ions less than 0.5 mole % and the clad has ions selected from the group consisting of transition metal ions, rare earth ions and a combination thereof. In addition, the phonon energy of a host material is less than 600 cm-1 and an absorption band at short-wavelength side is shorter than 530 nm.

The invention relates to a broadband air medium ultrasonic transducer with a phononic crystal matching and radiation composite structure. According to the structure of the broadband air medium ultrasonic transducer, a perforated matching plate capable of changing a vibration mode and acoustic matching is arranged on the radiation end surface of a shell, the perforated matching plate is provided with a piezoelectric element capable of generating a plane radial vibration mode in a stacking mode, and the piezoelectric element is used as an excitation source to excite the perforated matching plateto generate bending vibration and to radiate ultrasonic waves. The broadband air medium ultrasonic transducer improves acoustic matching of a conventional air medium ultrasonic transducer, can increase the bandwidth, improves the acoustic radiation of the transducer, and improves the resolution and range of action of the transducer.

Devices and systems for opto-acoustic signal processing are described herein. In one embodiment, the device may include a structure configured to laterally confine travelling acoustic phonons (hypersound) throughout, a first multimode optical waveguide embedded within the structure, and an acoustic phonon emitter within the structure, where the first multimode optical waveguide is selected to couple to the acoustic phonons (hypersound) confined within the structure. In one embodiment, the system may include a first light source optically coupled to a proximal end of the first multimode optical waveguide, the first light source emitting a probe wave having a frequency ω_p⁽¹⁾, and a driver configured to drive the acoustic phonon emitter to emit acoustic phonons (hypersound).

Efficient harmonic light generation can be achieved with ultrathin films by coupling an incident pump wave to an epsilon-near-zero (ENZ) mode of the thin film. As an example, efficient third harmonic generation from an indium tin oxide nanofilm (λ/42 thick) on a glass substrate for a pump wavelength of 1.4 μm was demonstrated. A conversion efficiency of 3.3×10⁻⁶ was achieved by exploiting the field enhancement properties of the ENZ mode with an enhancement factor of 200. This nanoscale frequency conversion method is applicable to other plasmonic materials and reststrahlen materials in proximity of the longitudinal optical phonon frequencies.

The device comprises an optical waveguide and an acoustic wave generating device. The waveguide has an optical band gap and a sharp electronic transition (e.g. an excitonic transition) in the band gap, and the acoustic wave generating device generates acoustic waves within the waveguide. Light passing through the waveguide is of a frequency within the band gap of the waveguide and is nearly resonant with the sharp electronic transition. The wave generating device is arranged to generate acoustic waves so as to induce optical band gas in the polariton spectrum, thereby affecting the transmission of the light passing through the waveguide, the transmission of which is thereby affected.

Provided is a phonon optical grating used for a superconductivity dielectric resonant cavity phonon laser device. The phonon optical grating comprises a buffer layer (1), a dielectric layer (2), an impurity layer (3), another dielectric layer (4) and another buffer layer (5), wherein the buffer layer (1) and the buffer layer (5) are arranged to enable the phonon optical grating to be matched with the size of a gap of the phonon laser device when the phonon optical grating is embedded in the emitting end of the superconductivity dielectric resonant cavity phonon laser device and to prevent the dielectric layer (2) and the dielectric layer (4) from being abraded, the dielectric layer (2) and the dielectric layer (4) are composed of two different materials in an alternately repeated mode, the impurity layer (3) is arranged between the dielectric layer (2) and the dielectric layer (4), and the dielectric layer (2), the impurity layer (3) and the dielectric layer (4) are in axial symmetry on the whole.

The confocal microscopic device capable of accurately measuring the transverse and longitudinal acoustic phonon velocities of the medium comprises a continuous laser, a three-dimensional translation stage and an F-P interferometer, a to-be-measured sample is placed on the upper side of the three-dimensional translation stage, and a measuring objective lens is arranged right above the to-be-measured sample; a lambda/2 wave plate, a polarizer, a light splitting plain film and a first reflecting mirror are sequentially arranged on one side of the continuous laser; and a confocal pinhole, a convergent lens, an analyzer, a rotary reflector and a second reflector are sequentially arranged on one side of the F-P interferometer. According to the invention, the angle between the incident light path and the scattered light path does not need to be changed in the measurement process, the acoustic phonon speed of the measured material is rapidly measured by dynamically switching the collected light paths, the in-situ property and accuracy of the measurement result are ensured, and the measurement efficiency is improved. The method has remarkable advantages in the aspects of measuring speed, measuring precision, measuring mode complexity and the like.