147 results about "Parametric oscillation" patented technology

A surgical technique for removing corneal tissue with scanned infrared radiation is disclosed which utilizes short mid-infrared laser pulses to provide a tissue removal mechanism based on photospallation. Photospallation is a photomechanical ablation mechanism which results from the absorption of incident radiation by the corneal tissue. Since photospallation is a mechanical ablation process, very little heat is generated in the unablated adjacent tissue. The disclosed surgical system includes a scanning beam delivery system which allows uniform irradiation of the treatment region and utilizes low energy outputs to achieve controlled tissue removal. A real-time servo-controlled dynamic eye tracker, based on a multiple-detector arrangement, is also disclosed which senses the motion of the eye and provides signals that are proportional to the errors in the lateral alignment of the eye relative to the axis of the laser beam. Temporal and frequency discrimination are preferably utilized to distinguish the tracking illumination from the ambient illumination and the surgical laser beam. A laser parametric generator for surgical applications is disclosed which utilizes short-pulse, mid-infrared radiation. The mid-infrared radiation may be produced by a pump laser source, such as a neodymium-doped laser, which is parametrically down converted in a suitable nonlinear crystal to the desired mid-infrared range. The short pulses reduce unwanted thermal effects and changes in adjacent tissue to potentially submicron-levels. The parametrically converted radiation source preferably produces pulse durations shorter than 25 ns at or near 3.0 microns but preferably close to the water absorption maximum associated with the tissue. The down-conversion to the desired mid-infrared wavelength is preferably produced by a nonlinear crystal such as KTP or its isomorphs. In one embodiment, a non-critically phased-matched crystal is utilized to shift the wavelength from a near-infrared laser source emitting at or around 880 to 900 nm to the desired 2.9-3.0 microns wavelength range. A fiber, fiber bundle or another waveguide means utilized to separate the pump laser from the optical parametric oscillation (OPO) cavity is also included as part of the invention.

An optical frequency comb generator includes a laser device arranged for generating input laser light having a predetermined input light frequency, a dielectric micro-resonator having a cavity exhibiting a third order nonlinearity, so that the micro-resonator is capable of optical parametric generation providing parametrically generated light, and a waveguide optically coupled to the micro-resonator, the waveguide being arranged for in-coupling the input laser light into the micro-resonator and out-coupling the parametrically generated light out of the micro-resonator, wherein the laser device, the waveguide and the micro-resonator being arranged for resonantly in-coupling the laser input light to a mode of the micro-resonator with a minimum power level so that an optical field inside the cavity exceeds a predetermined cascaded parametric oscillation threshold at which the parametrically generated light includes frequencies of frequency sidebands of the input light frequency and of the sidebands thereof.

Solid-state lasers pumped by incoherent or partially coherent, monochromatic light sources such as high power VCSEL arrays. Efficient and uniform injection of pumping energy into gain medium is achieved through spectral match of the pump source with the gain medium absorption and multi-bounce reflections of unabsorbed pump light in a diffusing pump chamber. One preferred embodiment of the diffusing pump chamber is a hollow cylinder coaxially surrounding the gain medium. One or more transparent windows, slit-shaped or otherwise, for transmission of pump light are evenly distributed around the perimeter of the chamber and are parallel to the axis. Another preferred embodiment of the diffusing pump chamber is a highly reflecting compound parabolic concentrator. A 2-D VCSEL array is employed as the pump source and the gain medium is located at the focusing point of the chamber. This invention demonstrates solid-state lasers that are compact, robust, low-cost, and able to produce high power output in CW or pulse modes for practical applications. An important application of the present invention is high-power solid-state lasers featuring wavelength conversion such as optical parametric oscillation and second-harmonic generation. Another important application of the present invention is injection seeding, especially for pulse mode with high repetition rates.

Solid-state lasers pumped by incoherent or partially coherent, monochromatic light sources such as high power VCSEL arrays. Efficient and uniform injection of pumping energy into gain medium is achieved through spectral match of the pump source with the gain medium absorption and multi-bounce reflections of unabsorbed pump light in a diffusing pump chamber. One preferred embodiment of the diffusing pump chamber is a hollow cylinder coaxially surrounding the gain medium. One or more transparent windows, slit-shaped or otherwise, for transmission of pump light are evenly distributed around the perimeter of the chamber and are parallel to the axis. Another preferred embodiment of the diffusing pump chamber is a highly reflecting compound parabolic concentrator. A 2-D VCSEL array is employed as the pump source and the gain medium is located at the focusing point of the chamber. This invention demonstrates solid-state lasers that are compact, robust, low-cost, and able to produce high power output in CW or pulse modes for practical applications. An important application of the present invention is high-power solid-state lasers featuring wavelength conversion such as optical parametric oscillation and second-harmonic generation. Another important application of the present invention is injection seeding, especially for pulse mode with high repetition rates.

The invention discloses a multi-wavelength terahertz wave parametric oscillator, which comprises a laser pump cavity and a terahertz wave parametric oscillation cavity, wherein the laser pump cavity consists of a totally reflecting mirror, a one-fourth wave plate, an electro-optical Q-switch device, a polarizer, a pulse laser pump source module, a micropore diaphragm and a laser output mirror; the terahertz wave parametric oscillation cavity comprises two right-angle prism resonance cavities respectively consisting of a right-angle prism, a reflector, a MgO:LiNbO3 crystal arranged between themicropore diaphragm and the laser output mirror, and a plurality of semi-circular output mirrors; and two silicon prism arrays are arranged on the surface of the MgO:LiNbO3 crystal. Pump light oscillating back and forth in the laser pump cavity is vertically transmitted to the MgO:LiNbO3 crystal, and two beams of oscillating Stokes light and two groups of four-beam terahertz waves are generated through excitation in the two right-angle prism resonance cavities, and are transmitted out of the silicon prism arrays. The continuous tunable output of the two groups of four-beam terahertz waves canbe realized, and the output energy is basically equal.

The invention discloses a certainty soliton mode locking method for a Kerr optical frequency comb in an optical microcavity. A pump laser power is set to be less than optical microcavity parametric oscillation threshold valve power; the generated pump laser is modulated; the frequency of a modulating signal is accordant with free frequency spectrum width of the optical microcavity; the amplitude of the modulating signal is obtained by calculating three-order dispersion value of the optical microcavity; the pump laser, after being subjected to phase modulation, enters the optical microcavity through a microcavity coupler in a coupling manner; the coupling coefficient is controlled to enable the optical microcavity to work in a critical coupling state; the pump laser is scanned from a long wavelength direction to a short wavelength direction in the optical microcavity; the spectrum of the output pump laser is collected at the output end of the optical microcavity; and in case that the current pump laser spectrum comprises a smooth envelope, the soliton mode locking is finished, and the scanning is stopped. According to the certainty soliton mode locking method for the Kerr optical frequency comb in the optical microcavity, the problems of high randomness, low reliability, high probability of disturbance and the like of the existing Kerr optical frequency comb mode locking scheme are overcame, so that the rapid and accurate soliton mode locking is realized.

A parametric oscillator oscillates a plurality of pseudo spin pulses SPi having mutually an identical oscillation frequency by using parametric oscillation, an interaction implementing unit performs feedback implementation of a magnitude and a sign of interaction related to each pseudo spin pulse SPi (the proportionality coefficient λi+ΣJijσj+ΣKijkσjσk with respect to σi) by using a tentative measurement result of oscillation phases φi(tentative) of the plurality of pseudo spin pulses SPi, and a pseudo spin measuring unit measures the pseudo spins σi of the plurality of pseudo spin pulses SPi, based on a final measurement result of oscillation phases φi(steady) of the plurality of pseudo spin pulses SPi.

The invention relates to a multifunctional coherent raman scattering biological imaging light source. Seed light output by a laser oscillator passes through primary and secondary amplification modules, so average power is improved, and a threshold value condition of parametric conversion is met. Amplified light enters a parametric conversion module through an optical coupler, so stokes light is generated and then is subjected to beam splitting through a power beam splitter. One part of the light is used as an imaging light source to be output and the other part enters a wavelength beam splitter, so separation of the stokes light and pump light is achieved. Separated light enters two repeated-frequency tuning modules which are capable of mutually independently controlling repeated frequencyof the stokes light and the pump light and are connected with a first-time time delay module and a second-time time delay module. Chromatic dispersion is adjusted, so two beams of feedback light passes the optical coupler and then is coupled to the parametric conversion module. Pump light and stokes light fed back to the optical coupler synchronize in time and coincide in space, so double parametric oscillation feedback is achieved. Thus, the high-efficiency multifunctional coherent raman scattering biological imaging light source is achieved.

An infrared laser in a self-optical parametric oscillation of double-cavity composite unsteady cavity mode selection pump relates to the laser field. A problem that the infrared laser in a self-optical parameter based on an Nd: MgO: PPLN crystal considers matching of high power and high beam quality base frequency light self-pump and a focusing parameter during a self-optical parameter oscillation process is solved. The laser comprises two laser diode pump sources, two energy transfer fibers, four focusing lenses, two 45 degree beam splitter mirrors, a parameter-oscillation-cavity totally-reflective mirror, a parameter oscillation cavity output mirror, the Nd: MgO: PPLN crystal, a temperature controller and an acousto-optic Q switch. Through adopting a double-cavity composite structure of a base-frequency optical resonant cavity and a parametric optical oscillation cavity, integration compactness is considered and simultaneously the two cavities completely work separately so that cavity-type structure parameter designs of the two cavities do not interfere with each other. Large base mode high beam quality base frequency optical pump can be realized, oscillation parameter light and base frequency light focusing parameters are highly matched, and energy conversion efficiency is high.

Optical parametric oscillator including a semiconductor microcavity being configured to spatially localize polaritons of at least three quantized polariton energy levels to effect an optical parametric oscillation.