37results about How to "High photodamage threshold" patented technology

The invention discloses a two-dimensional stratified material saturable absorber device which comprises a substrate. The substrate is a high reflection mirror plated with a back electrode, a dielectric layer and a two-dimensional stratified saturable absorption material are arranged on the high reflection mirror in sequence, an electrode is arranged on the two-dimensional stratified saturable absorption material in an evaporation mode, a voltage source is arranged between the electrode and the back electrode, an optical fiber pigtail is arranged above the two-dimensional stratified saturable absorption material, and the saturable absorption device is attached to the optical fiber pigtail. According to a method, the advantages of a two-dimensional stratified saturable absorber are inherited, such as high performance, low manufacturing cost and easy combination, and CW light and Pulse light can be switched over fast by adjusting grid voltages and freely adjusting the starting threshold value of a laser locking mold.

The invention relates to a three-dimensional measurement method for high-power laser body damage of a KDP (Potassium Dihydrogen Phosphate) crystal. The method substantially comprises the following steps of placing the KDP crystal to be measured into a detection optical path of a digital hologram interferometric device, and detecting a phase distribution outline of body damage in the crystal, i.e. a two-dimensional phase distribution image; carrying out angle scanning on the crystal to be measured, carrying out Fourier transform on the two-dimensional phase distribution image obtained from each angle sampling point, and constructing a three-dimensional phase distribution appearance of the body damage through the Fourier transform. The three-dimensional fine structure of the body damage can be utilized as an important parameter for qualitatively describing laser damage characteristics, and become a key environment correlated with laser damage macroscopic characteristics and micromechanisms and has important application to exploration of a KDP/DKDP (Deuterated Potassium Dihydrogen Phosphate) crystal laser damage mechanism and improvement of a laser damage threshold.

The invention discloses a graphene-based brand-new reflective type saturable absorber and a preparation method. The obtained saturable absorber comprises a saturable absorption layer, a reflective film layer and a substrate layer. The preparation method comprises the steps as follows: plating a gold film on a graphene thin film growing on a copper foil, reversing the gold film to face downward, binding with a silicon substrate the upper surface of which is plated with the gold film, contacting a smooth optical fiber end surface and graphene smoothly, and fixing and packaging the optical fiber and the absorber together. As the saturable absorber, the graphene has the advantages of being low in saturation strength, ultrafast in recovery time, adjustable in modulation depth, unrelated with wavelength, low in cost and the like, and by combining the specific structure advantage of the reflective type saturable absorber, the novel saturable absorber which is practical, simple and high-efficiency, stable in working property, high in optical damage and convenient for large-scale production can be realized.

The invention discloses a novel cone lens generating a single bottle beam, which is an axicon, wherein a concave circular truncated cone structure is formed at the bottom of the axicon, and the bottom angle of the circular truncated cone structure is less than that of the axicon. The novel cone lens can acquire the single bottle beam through one element, has the advantages of relatively easy element processing, simple structure, high conversion efficiency and high photo damage threshold, and provides a novel concise and efficient way for acquiring the bottle beam; furthermore, the size of the single bottle beam can be adjusted by adjusting the size of the bottom angle or the inner bottom radius of the circular truncated cone structure. In practical application, the novel cone lens can be used as laser conduits, optical tweezers, optical wrenches and other tools, and can be used for confining microscopic particles, neutral atoms, molecules, biological cells and the like by laser, thus has special significance in life science and nano-technology, in particular single-plane and multi-plane manipulation on microparticles.

The invention provides an optical fiber coupling-based high-polarization extinction ratio waveguide polarizer and a manufacturing method thereof. The invention aims to solve the problems of the high insertion loss and low optical power threshold of a lithium niobate annealed proton exchanged waveguide-based waveguide polarizer and further improve the polarization extinction ratio of such kind of devices. According to the optical fiber coupling-based high-polarization extinction ratio waveguide polarizer and the manufacturing method thereof of the invention, a magnesium oxide doped lithium niobate crystal or a near-stoichiometric lithium niobate crystal is adopted, so that the increase of the optical power threshold of the device can be realized; an anti-proton exchanged waveguide is prepared in the magnesium oxide doped lithium niobate crystal or near-stoichiometric lithium niobate crystal, so that the insertion loss of the waveguide is decreased; and the back surface of the magnesiumoxide doped lithium niobate crystal or near-stoichiometric lithium niobate crystal is slotted and is coated with a light absorbing material, so that the polarization extinction ratio of the waveguidepolarizer can be further improved.

The invention discloses a concave axicon capable of producing long distance non-diffraction beams. The concave axicon capable of producing long distance non-diffraction beams is provided with an axicon, wherein a cone angle of the axicon is gamma, an undersurface radius of the axicon is a, and an refractive index of the axicon is n. The axicon is divided into a cylinder part and a circular cone part along an axis direction, one end in which the cylinder part and the circular cone part are adjacent is the inside, the other end is the outside, and the outside undersurface of the cylinder part is in a concave spherical surface shape, wherein a center of the concave spherical surface shape is the axis of the axicon, and a curvature radius of the concave spherical surface shape is R. The long distance non-diffraction beams can be achieved through a single element, the problems that a cone angle of a traditional axicon is small and processing is hard are overcome, the concave axicon capable of producing the long distance non-diffraction beams has the advantages of being easy in element processing, simple in structure, high in transfer efficiency, and high in optical damage threshold value, a concise and effective new way is provided for acquiring the long distance non-diffraction beams, and in addition, non-diffraction distance of the non-diffraction beams can be adjusted through adjusting radii of incident beams and a size of the curvature radius of the undersurface of the concave axicon.

The invention belongs to the field of optics and concretely relates to a preparation method of a silica-base broadband saturable absorber device. The preparation method mainly includes the following steps: firstly, preparing broadband saturable absorber sol, and secondly, dispensing the prepared broadband saturable absorber sol in a D type zone of a D type fiber, and then obtaining a broadband saturable absorber device after the sol stands to become gel. A sol-gel method is adopted to prepare broadband saturable absorbers, and the absorbers are uniformly distributed in silica sol to effectively isolate the air and form a great protection substrate, so oxidation is prevented, a light injury threshold is increased, and the use stability is improved. The broadband saturable absorbers can be used for an all-fiber evanescent wave mode locked fiber laser and can greatly reduce insertion loss, so unsaturated loss of the broadband saturable absorber device is reduced. The prepared broadband saturable absorbers are convenient to use and convenient for industrial popularization.

The invention relates to a communication signal source, in particular to a photonic crystal fiber laser. The photonic crystal fiber laser comprises a pump light source, an optical coupler and a photonic crystal fiber, wherein the optical coupler enables light emitted by the pump light source to be coupled in the photonic crystal fiber, and light reflection parts are arranged at two ends of the photonic crystal fiber to form an optical resonant cavity. The communication signal source is characterized in that the photonic crystal fiber is provided with a rare earth adding core where rare earth elements are added, a covering layer formed around the rare earth adding core and a plurality of through holes formed on the covering layer. Excitation light enters from the end of the covering layer, the rare earth elements are excited to output high-power laser oscillation light, and the through holes are filled with a liquid material with the dielectric constant ranging from 1.6 to 2.8.

The invention discloses a broadband strong-field terahertz source based on a silicon carbide single crystal. The broadband strong-field terahertz source comprises a femtosecond pulse laser source, a wavefront tilting system, a silicon carbide wafer and a coupling output end. The femtosecond pulse laser source part comprises a femtosecond laser and a plane mirror, the wavefront inclination system part comprises a reflection grating, a half-wave plate and a telescope imaging lens group, femtosecond laser is normally incident to a silicon carbide wafer after passing through a wavefront inclination system, terahertz pulse radiation is generated in the wafer in a light rectification mode, and the terahertz pulse radiation is transmitted to the femtosecond laser; terahertz pulse radiation is coupled and output through the triangular prism silicon prism at the coupling output end. Wherein the thickness of the silicon carbide wafer is 0.5-6 mm, the wavefront inclination angle of pulses in the wafer is 31.5-38 degrees, three cylindrical surfaces of the triangular prism silicon prism are subjected to optical polishing treatment, the cutting angle of the terahertz output surface of the triangular prism silicon prism is 31-32 degrees, and the input surface of the triangular prism silicon prism completely covers and is attached to the output surface of the silicon carbide wafer through an optical contact method.