24 results about "Nonlinear absorption" patented technology

A ring resonator (10) and a NALM (20) configured as a saturable absorption mechanism constitute a laser oscillator. A multiport BPF (12) is provided to a path through which light propagates in the laser oscillator, the multiport BPF (12) passing light in a prescribed band of the propagating light, and branching light outside of the prescribed band as monitoring light (L). A photodetector (1) detects the monitoring light (L). A control unit (2) controls the oscillation state of the light propagating through the laser oscillator on the basis of the intensity of the monitoring light (L), thereby controlling the mode synchronization of the light propagating through the laser oscillator.

The invention provides Nd-doped molybdenum disulfide with adjustable near-infrared nonlinear absorption and a preparation method of the Nd-doped molybdenum disulfide, belongs to the technical field of nano materials, and aims to solve the technical problem of poor near-infrared photoelectric property of MoS2. The preparation method of the Nd-doped molybdenum disulfide comprises the following steps: dissolving a molybdenum source, a sulfur source, a neodymium source and a reducing agent into a solvent to prepare a reaction solution, and performing solvothermal reaction to prepare the Nd-doped molybdenum disulfide nano material. The prepared MoS2 nanosheet is rich in VS, and the band gap of the MoS2 nanosheet is reduced to 0.75 eV and is obviously lower than the standard band gap (1.28-1.98 eV) of intrinsic MoS2, so that the nonlinear optical response at the wavelength of 1064 nm is successfully realized, the SA effect is shown, and the MoS2 nanosheet can be applied to devices such as a saturable absorber, an optical switch and a laser mode locker. Furthermore, by introducing Nd < 3 + > for doping, controllable conversion of nonlinear absorption behavior from SA to RSA along with light intensity change is realized.

The invention relates to the field of laser processing, in particular to a glass three-dimensional curved surface femtosecond laser welding method based on space-time focusing and multi-physics field coupling. Comprising the following steps: combining multiple beams of femtosecond laser, infrared laser and ultraviolet laser, regulating and controlling through a synchronous space-time focusing system, coaxially combining the beams to one light path in space, respectively focusing at the joints of the three-dimensional curved surface of the glass, and realizing initial melting by utilizing nonlinear absorption induced by the femtosecond laser, infrared laser enhances heating and fusion depth control, and ultraviolet laser performs nanometer remelting treatment on the edge of a welding seam, so that the welding compactness and the bonding strength are improved; in the infrared laser welding process, low-frequency ultrasonic waves are introduced to regulate and control a molten pool microstructure and release residual stress, wavefront regulation and control, an AI module and interference feedback are matched, high-stability closed-loop welding control under the synergistic effect of multiple physical fields is achieved, and the glass welding efficiency, adaptability and welding quality are remarkably improved.

The invention provides a method for regulating and controlling the nonlinear absorption type of a DAST-based composite film and a preparation process of the DAST-based composite film, and relates to the technical field of nonlinear optical materials. The method comprises the following steps: compounding a guest photoelectric sensitive material DAST and a subject flexible material PMMA by adopting a blade coating technology to obtain a binary DAST / PMMA subject-guest composite film; during the process, the mass fraction of the object photoelectric sensitive material in the composite film is adjusted, so that mutual conversion between a nonlinear anti-saturated absorption behavior and a saturated absorption behavior of the composite film in a femtosecond trepanning Z scanning laser system is successfully realized. Compared with existing nonlinear absorption type regulation and control technologies such as band gap engineering of two-dimensional inorganic materials, micro-nano structure construction of organic materials, functional group modification and the like, the regulation and control method is simpler, lower in cost and more beneficial to industrial processing, and has good practical application potential in the fields of laser protection, laser mode locking, optical switches and the like.

The invention provides a high repetition frequency mode-locking external cavity semiconductor laser. The high repetition frequency mode-locking external cavity semiconductor laser comprises a saturable absorber region, a gain region, a phase adjustment region, a light splitting region and a micro-ring resonance region. The phase adjusting area, the light splitting area and the micro-ring resonance area form an outer cavity, the gain area provides optical gain, one side of the saturable absorption area is plated with a high-reflection film, and the saturable absorption area and the outer cavity structure jointly form an optical resonant cavity. When free spectrums of the Fabry-Perot resonant cavity and the micro-ring resonant cavity are accurately matched, the repetition frequency of the laser can be multiplied, passive mode locking is realized through the nonlinear absorption characteristic of the saturable absorber, and high repetition frequency pulse output is formed. The scheme provided by the invention has the advantages of high integration level, high stability, high repetition frequency and the like, and has important application value in the fields of data centers, optical communication, high-speed optical sampling, double-optical comb measurement and the like.

The invention provides a large-modulation-depth dynamic saturable absorber mirror and a preparation and working method thereof, the large-modulation-depth dynamic saturable absorber mirror comprises a vanadium dioxide nano film and a gold film silicon substrate high-reflection mirror, and the film is deposited on the upper layer of a gold film of the gold film high-reflection mirror through a direct current magnetron sputtering technology to form a dynamic saturable absorber mirror device; the core mechanism is that when the dynamic saturable absorption mirror is driven by enhanced light intensity in a cavity, phase transformation and optical property dynamic transformation occur, starting from low reflectivity and high loss of a vanadium dioxide insulating phase, the state is converted into a vanadium dioxide mixed phase saturable absorption state through phase transformation equivalent nonlinear absorption, and then the state is converted into a metallic state saturable absorption state; and finally, the metal-state saturable absorption is completely saturated, so that the large-modulation-depth dynamic saturable absorption mirror is realized. According to the invention, the modulation depth of the saturable absorber mirror can be effectively improved and flexibly adjusted; and the basic temperature of the device can be regulated and controlled in a passive / active manner, so that the universality and adaptability of system application are enhanced.

The invention discloses a preparation method and application of a wafer-level palladium ditelluride-palladium diselenide vertical heterojunction thin film for a nonlinear saturable absorber. The structure of the material sequentially comprises a palladium ditelluride thin film and a palladium diselenide thin film from top to bottom, and the wafer-level two-dimensional palladium ditelluride-palladium diselenide thin film vertical heterojunction is prepared by adopting a chemical vapor deposition technology assisted by electron beam evaporation coating. Experimental results show that the nonlinear absorption performance of the obtained heterojunction thin film is superior to that of a single palladium ditelluride thin film in a visible wave band of 550 nm; in the near-infrared band of 1550 nm, the modulation depth can reach 31.92%, and the wide-spectrum response characteristic from the visible band to the near-infrared band is shown. The material obtained by the invention has the advantages of controllable wafer-level growth, excellent nonlinear performance, wide operating wavelength range and the like, provides important material strategy and theoretical support for the design of ultrafast photonic devices such as high-performance mode-locked lasers and all-optical switches, and has important application value.

The invention relates to a method and a system for manufacturing a polarizing body holographic grating (PVG) lens. The method comprises the following steps: a) providing a PVG lens blank; b) scanning on the PVG lens blank by using a first wavelength laser beam along a preset cutting path to form a stress concentration line; and c) scanning along the same cutting path by using a laser beam with a second wavelength, and applying thermal stress loading to the stress concentration line to guide the crack to expand from the stress concentration line so as to separate the lens blank along the cutting path. According to the invention, a two-step separation method of internal preset fracture path and external thermal shock guiding is adopted. A first wavelength laser beam (such as ultrafast laser of picosecond and the like) can form an accurate and lossless microscopic modified chain as a stress concentration line in a substrate through nonlinear absorption under the condition of not damaging the surface of a material due to the cold working characteristic of the first wavelength laser beam. The surface micro-cracks are eradicated from the source. And a second wavelength laser beam (such as infrared laser of COs and the like) generates a moving and high-gradient thermal stress field on the surface of the substrate along a preset path by utilizing the thermal effect of the second wavelength laser beam. And the stress field accurately acts on the internal fragile stress concentration line to guide cracks to controllably and smoothly expand, so that mechanical-contact-free guided fracture is realized.

The application relates to a method for enhancing the nonlinear optical performance of SnS2 nanosheets through electrostatic doping. First, SnS2 nanosheets are prepared on a fluorine-doped tin oxide (FTO) substrate by a chemical vapor deposition method, and then hydrogen ion intercalated SnS2-H + The electrostatic doping causes the band gap to shrink and a strong built-in electric field to be generated, so that the nonlinear optical performance of the material is enhanced. In addition, the saturated absorption response of the material enables the application to an optical neural network as a nonlinear activation function, and exhibits application potential in machine learning tasks. The SnS2-H + The application establishes a promising and convenient nonlinear optical material, and provides new insights for the design exploration and simple synthesis of high-performance nonlinear absorption materials.

This application provides a tunable optical pulse source chip, relating to the field of semiconductor optoelectronic integrated device technology. The optical pulse source chip includes: a gain region for generating and amplifying an optical signal; a pulse selection region for receiving an external periodic electrical signal to form a periodically switching switching window, through which the amplified optical signal passes or is blocked; and a saturable absorption region for nonlinearly absorbing the optical signal passing through the pulse selection region to achieve mode locking, thereby generating and outputting an optical pulse. The repetition frequency of the optical pulse is tunable by controlling the frequency of the periodic electrical signal. This application integrates the gain region, pulse selection region, and saturable absorption region monolithically, and uses a periodic electrical signal to control the switching window of the pulse selection region. The output optical pulse repetition frequency is independently controlled by the frequency of the external electrical signal, decoupling the repetition frequency from the cavity length, thus enabling a wide-range, continuously tunable pulse repetition frequency.

The invention relates to the technical field of optical neural networks, in particular to a nonlinear absorption film and a preparation and regulation method thereof. The nonlinear absorption thin film comprises a continuous film layer formed by stacking gallium indium tin liquid metal nanoparticles. Therefore, the gallium-indium-tin liquid metal in the thin film exists in the form of nano-particles, and the nano-sized gallium-indium-tin liquid metal enables the thin film to have local surface plasma resonance absorption characteristics, so that the thin film has nonlinear optical response.

The invention discloses a laser coupling system and laser processing equipment. The laser coupling system comprises a first laser source, a second laser source and a third laser source which are used for providing three beams of laser; the polarization preprocessing module is used for adjusting the polarization states of lasers emitted by the first laser source and the second laser source to be in a preset relation and combining the lasers into first combined light, and the first combined light comprises laser components of the first polarization state and the second polarization state; the electric control polarization switching module is arranged on a light path of the first combined light beam and used for receiving signals and modulating the overall polarization state of the first combined light beam; the polarization beam splitting and combining module is provided with a main input end, an auxiliary input end and an output end, the main input end receives the modulated light beam, the auxiliary input end receives the laser emitted by the third laser source, and second combined beam light is formed through selective coupling. According to the technical scheme, coupling of the main laser and the auxiliary laser can be flexibly switched, under the condition that the total energy is lower than the energy needed by the single-beam main laser to reach the threshold value, nonlinear absorption and modification of the material can be efficiently triggered, and precise machining threshold value breakthrough under lower energy input is achieved.

A method for preparing and / or carrying out the structuring of a predetermined or predeterminable distinguished surface of a substrate body having a substrate material includes exposing the substrate material in at least one curved effective area to an electromagnetic field which in each of the at least one curved effective area causes a non-linear interaction between the electromagnetic field and the substrate material, and thus at least partially influencing the substrate material arranged in the curved effective area. After the structuring of the distinguished surface the distinguished surface has at least in certain areas at least one first curved progression which is at least partially determined and / or influenced by the curved shape of the at least one curved effective area. The nonlinear interaction causes at least one nonlinear absorption of the electromagnetic field in the substrate material.

This invention relates to the field of optical imaging system technology, and more particularly to an optical imaging system for continuous protection against pulsed laser-induced blindness. The system includes a secondary imaging optical system, an imaging detector, a nonlinear absorption-type optical limiter, and a two-dimensional moving unit. The secondary imaging optical system comprises a primary imaging optical component and a secondary imaging optical component. After the light beam enters the secondary imaging optical system, it is focused by the primary imaging optical component to form a primary image focal point, and then imaged onto the imaging detector by the secondary imaging optical component. The nonlinear absorption-type optical limiter is mounted on the two-dimensional moving unit and positioned near the primary image plane of the secondary imaging optical system's principal optical axis. The two-dimensional moving unit drives the movement of the nonlinear absorption-type optical limiter, allowing the incident light beam to pass through different positions on the nonlinear absorption-type optical limiter. The advantage is that it provides continuous laser protection for the imaging detector, achieving automatic protection for the optical imaging system.

This invention provides a multiphysics-coupled molecular dynamics simulation method and system for femtosecond laser ablation, comprising: establishing an atomic model of a wide-bandgap semiconductor material and its corresponding electronic grid; inputting laser parameters and material parameters and initializing field variables; introducing a carrier concentration evolution equation and updating the laser intensity distribution within the material based on the Drude model; considering the bandgap energy consumption term of the valence band electron transition process under femtosecond laser irradiation, improving the laser heat source term in the electronic temperature equation, updating the electronic temperature, and then obtaining the atomic-scale behavioral evolution through energy exchange between the electronic system and the lattice system, and outputting the results. This invention introduces the nonlinear absorption of femtosecond laser ablation of wide-bandgap semiconductor materials into a dual-temperature model-molecular dynamics model coupling framework, realizing a unified coupled simulation of energy deposition, carrier evolution, transient optical response, and material removal behavior of wide-bandgap semiconductor materials under femtosecond laser irradiation.

The application discloses a method for regulating nonlinear optical properties of reduced graphene oxide by Au@CdS and an rGO-Au@CdS composite material, the Au@CdS core-shell structure is uniformly grown on the surface of the reduced graphene oxide, the core-shell structure is closely connected with the reduced graphene oxide, the rGO-Au@CdS composite material is successfully synthesized by using a solvothermal method, the nonlinear absorption of the composite material has the characteristic of transition from saturated absorption to reverse saturation, and the characteristic is more and more obvious with the increase of light intensity. With the increase of the size of the Au@CdS composite structure, the intensity of the reverse saturation absorption is also improved.

This invention discloses a laser pulse protective cladding based on nonlinear optical effects. Along the laser transmission direction, it sequentially comprises a first homogeneous dielectric layer, a first nonlinear absorbing dielectric layer, and a second homogeneous dielectric layer, wherein the dielectric constant of the first nonlinear absorbing dielectric layer is greater than that of the first and second homogeneous dielectric layers; or, along the laser transmission direction, it sequentially comprises at least two stacked structural units, each stacked structural unit comprising a homogeneous dielectric layer and a nonlinear absorbing dielectric layer; or, along the laser transmission direction, it sequentially comprises a third homogeneous dielectric layer and at least two reflective structural units, each reflective structural unit comprising a homogeneous dielectric layer and a nonlinear absorbing dielectric layer. The embodiments of this invention can reduce the harm of high-intensity lasers to people or objects, providing a laser protection measure that can be widely applied in the field of laser application technology.

The invention discloses a femtosecond laser induced fused quartz surface oxygen vacancy defect micro-area prefabrication and selective repair method and system, and belongs to the field of laser precision machining and optical material modification. According to the method, irradiation parameters of femtosecond laser on the surface of fused quartz in an oxygen-containing atmosphere are controlled, and the nonlinear absorption effect of the femtosecond laser is utilized, so that two functions are realized: firstly, oxygen vacancy defects with quantitative concentration can be controllably prefabricated in a specified micro-area, and the problem that atomic-scale defects are difficult to position and characterize is solved; and 2, performing selective bonding repair on the positioned oxygen vacancy defect, so that the chemical composition of the defect area is recovered to be close to an ideal stoichiometric ratio. According to the system, a visual positioning module, a parameter mapping module and a cooperative control module are integrated, and full-automatic accurate operation is achieved. The surface roughness change of the area repaired through the method is smaller than 0.04 nm, the method has the advantages of being free of damage, controllable and high in precision, and an effective technical approach is provided for improving the laser damage threshold value of the fused quartz optical element.

This application provides an optical fiber coupling end for femtosecond laser transmission optical cables, including a substrate with an internal through-hole in the center of the substrate, a fiber fixing tube sleeved inside the internal through-hole, a front sleeve and a rear sleeve respectively at both ends of the substrate, the fiber fixing tube having a hollow inner cavity, the hollow inner cavity communicating with the interior of the front sleeve and the rear sleeve, one end of the rear sleeve being connected to the optical cable, the hollow fiber in the optical cable passing through the rear sleeve to extend into the hollow inner cavity, the end of the hollow inner cavity near the front sleeve having an optical fiber sleeve, the optical fiber sleeve fixing the hollow fiber end, an annular cavity between the internal through-hole and the fiber fixing tube, the substrate having a water inlet and a water outlet communicating with the annular cavity, which solves the problem of heat accumulation at the coupling end face of femtosecond laser transmission optical fibers, and allows for convenient structural optimization by using vacuum to solve problems such as nonlinear absorption and pulse width expansion of the laser.

According to the method and system for modifying the two-dimensional material through the laser and the two-dimensional material, the two-dimensional material to be machined is fixed to the electrode and leveled, the accuracy and stability of the relative position between the area to be modified and the laser focus in the subsequent laser machining process are guaranteed, and a solid foundation is laid for high-precision modification. Ultrafast laser parameters of an ultrafast laser are set, the requirement that the pulse width is larger than 1 ps is determined, and the unique cold machining mechanism of interaction of ultrafast laser and substances is fundamentally utilized; when ultrafast laser with the pulse width larger than 1ps acts on the two-dimensional material, laser energy is absorbed within the time scale far faster than material lattice thermal diffusion due to the extremely high peak power and the extremely short acting time of the ultrafast laser, the nonlinear absorption process is mainly triggered, and therefore accurate removal or modification of the material can be achieved with extremely small thermal influence, and the material can be effectively removed or modified. And melting, splashing and thermal damage caused by traditional long-pulse laser processing are avoided.

The invention provides an indium tin oxide thin film for enhancing terahertz emission and a preparation method of the indium tin oxide thin film, and belongs to the technical field of nonlinear optics and terahertz. The method comprises the following steps: depositing an indium tin oxide (ITO) film on a substrate by adopting a magnetron sputtering process; and the thin film is placed in a vacuum environment to be subjected to rapid thermal annealing treatment. The core of the method is that the annealing time and the annealing temperature are accurately controlled, and the thin film is regulated and controlled to be in a middle semitransparent state which is converted from opaque to full-transparent. Experiments show that the ITO thin film in the semitransparent state maintains high nonlinear absorptivity in a near-infrared pumping wave band while ensuring certain crystallization quality, so that the emission intensity of terahertz generated by the ITO thin film is obviously higher than that of a full-transparent thin film which is annealed for a long time. According to the terahertz emission source, the problem that the nonlinear optical conversion efficiency is reduced due to excessive pursuit of film transparency in the prior art is solved, and a terahertz emission source preparation scheme which is simple in process, compatible with a CMOS (complementary metal oxide semiconductor) process and efficient is provided.

The invention provides a nonlinear absorption-based perovskite type all-optical diode which comprises a saturated material and an anti-saturated material, and the nonlinear absorption-based perovskite type all-optical diode is formed by connecting a saturated absorption perovskite material and an anti-saturated absorption perovskite material in series. The perovskite type all-optical diode based on nonlinear absorption has the advantages of being passive, easy to prepare, free of polarization dependence, free of phase matching requirements, adjustable in thickness and small in size, and is more suitable for being used in an integrated optical path. Meanwhile, due to the fact that the band gap of the perovskite material is adjustable, the band gap of the material can be changed by adjusting halide ions, the nonlinear absorption characteristic of the material is further influenced, the all-optical diode suitable for the broadband is achieved, research which is relatively lacked in the wave band of 700-900 nm at present is supplemented, perovskite is applied to non-reciprocal optical devices, and the photoelectric conversion efficiency is improved. And the application range of the perovskite is widened.

The application relates to the field of two-dimensional materials, and specifically provides a two-dimensional van der Waals heterojunction and a preparation method and application thereof. The heterojunction comprises a first material layer and a second material layer, and the first material layer and the second material layer interact with each other through van der Waals force; the first material layer is a saturated absorption material, and the second material layer is an anti-saturated absorption material. In the preparation, the second material layer is prepared on a substrate first, and then the first material layer is prepared on the second material layer; the first material layer and the second material layer are prepared by using one of physical vapor deposition, chemical vapor deposition, liquid phase stripping and magnetron sputtering. The heterojunction disclosed in the application can be used for all-optical diodes. The heterojunction comprises saturated absorption and anti-saturated absorption materials; when laser irradiation exists, the nonlinearity of non-reciprocal absorption and the charge transfer effect of the heterojunction interface exist simultaneously, so that the non-reciprocal factor F and the symmetry S of transmittance are increased, and therefore the performance of the heterojunction for all-optical diodes is good.

The application discloses a preparation method of a wafer-level two-dimensional palladium ditelluride-palladium diselenide vertical heterojunction film for a nonlinear saturable absorber and application thereof. The structure of the material comprises, from top to bottom, a palladium ditelluride film and a palladium diselenide film, and the wafer-level two-dimensional palladium ditelluride-palladium diselenide vertical heterojunction is prepared by using an electron beam evaporation film plating assisted chemical vapor deposition technology. Experimental results show that the obtained heterojunction film has a nonlinear absorption performance superior to that of a single palladium ditelluride film in a 550 nm visible waveband; in a 1550 nm near-infrared waveband, the modulation depth can reach 31.92%, and the wide-spectrum response characteristics from the visible to the near-infrared waveband are exhibited. The obtained material has the advantages of controllable wafer-level growth, excellent nonlinear performance and wide working wavelength range, and provides important material strategies and theoretical support for the design of high-performance mode-locked lasers, all-optical switches and other ultrafast photonic devices, and has important application value.