22 results about "Laser threshold" patented technology

This invention discloses a YAG-based composite laser ceramic and its preparation method. The composite laser ceramic has a five-layer structure from top to bottom: a microstructured concave YAG transparent ceramic, an Nd:YAG transparent ceramic, a YAG transparent ceramic I, a Ce,Nd:YAG transparent ceramic, and a YAG transparent ceramic II. The microstructured concave YAG transparent ceramic is used to reduce the temperature gradient and compensate for the thermal lensing effect; the Nd:YAG transparent ceramic is used to collect the energy emitted by the microstructured concave YAG transparent ceramic and to transfer the energy; the Ce,Nd:YAG transparent ceramic is used for laser energy transfer; and the YAG transparent ceramic I and YAG transparent ceramic II are used to reduce the ceramic thermal lensing effect. It is prepared using thermal bonding technology. The composite laser ceramic of this invention emits bright yellow light near 1064 nm when excited by a laser with a pump source of 808 nm. Furthermore, the composite laser ceramic has a light-to-light conversion efficiency of 19.85% and a laser threshold of 410 mW.

The utility model relates to the technical field of laser equipment, in particular to a laser assembly, a solid-state laser and laser processing equipment, and the laser assembly comprises a birefringent crystal which is used for emitting solid-state laser under the pumping effect, and the solid-state laser comprises two pieces of orthogonal polarized light with different wavelengths; the Q switch is arranged at one end of the birefringent crystal and is used for controlling the output of the solid-state laser; and the dual-wavelength output coupler is arranged at one end, deviating from the birefringent crystal, of the Q switch and is used for coupling and outputting two orthogonal polarized lights in the solid-state laser. Through the mode, the energy loss in the laser pumping cavity can be reduced, so that the laser threshold value is reduced, and the laser output power is improved.

A method of accounting for signal noise in a hybrid laser system is described. The hybrid laser system includes a high reflectivity mirror, a nitrogen-vacancy center diamond, a microwave antenna, a dichroic mirror, a half-vertical cavity surface emitting laser (VCSEL), a birefringent filter, an etalon, an output coupler, and a photodiode. The method includes: measuring a shift in a left-hand side frequency as related to an optically detected magnetic resonance (ODMR) frequency peak of an ODMR signal; measuring a shift in a right-hand side frequency as related to the ODMR frequency peak; normalizing the shift in the left-hand side frequency; normalizing the shift in the right-hand side frequency; and comparing the shift in the left-hand side frequency to the shift in the right-hand side frequency to determine a technical noise associated with the ODMR signal.

Light-emitting device configured to emit radiation, comprising: a substrate (50); an epitaxic structure (20) comprising in succession a first DBR stack (21), a light-emitting stack (22), a second DBR stack (23) and several discrete first and second contact regions (241), wherein the light-emitting device emits coherent light having a far-field angle of less than 15 degrees, at a forward current between a laser threshold current and a saturation current therein, and incoherent light at a forward current less than the laser threshold current, wherein the epitaxial structure (20) is arranged on the substrate (50) and further comprises: several first radiation-emitting areas in a first column; and several second radiation-emitting areas in a second column; a conductive layer (60) on the epitaxial structure (20); wherein the contact areas (241) are arranged in a two-dimensional field and are configured to direct a spatially limited current in the light-emitting device to the several first radiation-emitting areas and the several second radiation-emitting areas; and wherein one of the several first contact areas includes a first latitude (w3') and one of the several second contact areas includes a second latitude (w3) that differs from the first latitude (w3').

The application discloses a preparation method of full-color laser carbon dots based on rhodamine B derivation, which comprises the following steps: ultrasonic dispersion of rhodamine B in a liquid solvent, continuous heating in an autoclave, and preparation of green, yellow, red and near-infrared light carbon dots after filtration, elution, purification and freeze-drying; when rhodamine B is mixed with NaOH or KOH solid, heating is carried out in a beaker to prepare blue light carbon dots; in the application, rhodamine B is used as a precursor, and the carbon dots are synthesized by a solvothermal method; the excellent gain performance of rhodamine B is expanded from orange and red to the whole visible light and near-infrared light region; even the emission effect can be enhanced through cross-linking; the gain performance of the carbon dots is higher than that of rhodamine B, and the carbon dots have higher fluorescence quantum yield, higher radiation transition rate, lower laser threshold and more excellent laser stability.

The present application relates to a kind of based on optical wavefront shaping and acoustic focusing to realize multimodal photoacoustic angiography method, comprising the following steps: carrying out regional positioning output optimal matching region coordinate, excitation optimal matching region coordinate photoacoustic effect;Focus on laser by wavefront shaping module;Through pulse generator excitation ultrasonic transducer generates ultrasonic pulse;Photoacoustic pressure wave signal and ultrasonic signal are in turn through amplification filter and analog-digital converter;The excited photoacoustic pressure wave and ultrasonic signal are in turn through acoustic focusing adjustment module enhancement;Digital enhancement photoacoustic signal and enhanced ultrasonic signal are carried out image reconstruction.The present application is based on optical wavefront shaping and acoustic focusing to realize multimodal photoacoustic angiography method, system, device, processor and its computer readable storage medium, improve laser energy utilization efficiency, reduce laser threshold, reduce equipment cost, improve deep tissue photoacoustic signal intensity and distribution uniformity.

The application discloses a multi-pass uniform pumping laser device based on blackbody absorption, which comprises a pumping light source, a waveguide and a solid laser medium arranged along an optical path, and a curved surface reflecting device which is arranged on the same side of the pumping light source relative to the solid laser medium and forms a blackbody structure with the solid laser medium, and is used for reflecting the pumping light emitted after being absorbed by the solid laser medium back to the solid laser medium, so that the solid laser medium absorbs the pumping light for multiple passes, and generates and laterally outputs a laser beam. The application utilizes the curved surface reflecting device and the solid laser medium to form a blackbody structure to absorb the pumping light for multiple passes, increases the absorption length of the solid laser medium, can realize uniform pumping, reduces the thermal gradient, reduces the laser threshold, and improves the laser efficiency.

The application discloses a kind of for single-color multimode laser output spherical host-guest type micro-nano laser and its preparation method, the micro-nano laser is by the spherical metal organic hybrid material host with distortion topological network structure and laser dye guest composition.Wherein the composition of spherical metal organic hybrid material host is:Zn, organic ligand 2,4,6-tri (3,5-dicarboxyphenyl amino) -1,3,5-triazine, N,N-dimethylformamide.Guest is laser dye.The application is based on spherical metal organic hybrid material as the resonant cavity of micro-nano laser, utilizes its super-smooth surface and excellent circular boundary, avoids boundary scattering loss, effectively provides sufficient feedback for laser oscillation, realizes single-color multimode laser output with high quality factor, narrow half-width, wide mode interval and low laser threshold.Effectively solve the problem that existing micro-nano laser is mostly crystal material, and there is a lot of boundary scattering loss.

The invention discloses a wavelength-adjustable hybrid plasmon micro-nano laser based on TPP and SPP, and belongs to the technical field of lasers, and the wavelength-adjustable hybrid plasmon micro-nano laser comprises a one-dimensional photonic crystal heterostructure based on surface plasmon and Tamm plasmon polariton mode coupling; the one-dimensional photonic crystal heterostructure is formed by stacking a plurality of layers of thin films and sequentially comprises a metal layer, a dielectric spacer layer, a distributed Bragg reflector (DBR) and a substrate from top to bottom. According to the invention, hybridization of two different optical modes is adopted, so that the interaction between surface light and substances is enhanced. Compared with a TPP mode and an SPP mode, the hybrid mode solves the problem of large metal loss and improves the Q value. In the application of the laser, the high Q value characteristic and the Purcell effect of a hybrid mode are utilized, and a four-level gain system is introduced to effectively compensate the loss, so that the laser threshold is remarkably reduced, and the problem that the plasmon laser threshold is too high is solved.

The application provides a 3*3 coupler optimized self-starting O-band eight-character cavity mode-locked laser, relates to the technical field of fiber communication and nonlinear optics, and comprises a pump light source, a wavelength division multiplexer, a bismuth-doped optical fiber, a 1*2 coupler, a 3*3 coupler, an isolator and a polarization controller; the wavelength division multiplexer, the bismuth-doped optical fiber, the 1*2 coupler and the polarization controller form a main ring, the isolator forms a mirror ring, and the main ring and the mirror ring are connected through the 3*3 coupler. The laser constructed by the application utilizes the 120-degree or 2pi / 3 phase shift provided by the 3*3 coupler, significantly reduces the self-starting laser threshold and improves the output power, has a higher power damage threshold compared with a conventional saturable absorbing material, and is a high-efficiency and stable solution provided for the technical field of optical communication and laser.

This invention discloses a functional polymer / liquid crystal composite semiconductor micro / nano laser and its fabrication method. This laser utilizes the Rayleigh instability of the cylindrical liquid interface to form a functional polymer / liquid crystal spindle structure with a specific morphology on the surface of semiconductor micro / nanowires. This constructs a composite optical microcavity that enhances optical field confinement and suppresses radiation loss, thereby improving the quality factor of the resonant cavity, compressing the resonant linewidth, and lowering the laser threshold. Furthermore, by controlling the size parameters of the functional polymer / liquid crystal spindle and its coverage position on the semiconductor micro / nanowire surface, effective control of the resonant mode is achieved. Based on the relevant properties of the semiconductor material and the polymer / liquid crystal cladding material, this invention exhibits excellent photostability under pulsed light pumping and long-term detection conditions, significantly enhancing the device's specific recognition capability of analyte molecules and its high-sensitivity sensing performance.

The application discloses a Q-switched laser resonator single-pass loss simulation inversion calculation method and system, and belongs to the technical field of laser simulation. The method comprises the following steps: initializing basic parameters related to a resonator and a laser medium; calculating a laser threshold energy storage according to the basic parameters; calculating the energy storage of a laser crystal under different pump currents according to the laser threshold energy storage; calculating the output energy simulation value under each pump current according to the energy storage of the laser crystal; comparing the output energy simulation value with the actual measured value, and obtaining the final simulation result of the resonator single-pass loss according to the comparison result. The application does not need a large number of experimental tests, has low simulation error, is suitable for multiple pump working conditions, is applicable to the loss solving and performance optimization of various Q-switched solid-state lasers, and can significantly improve the laser design efficiency and simulation precision.

The application discloses a wavelength-controllable hybrid plasmonic micro-nano laser based on TPP and SPP, and belongs to the technical field of lasers, comprising a one-dimensional photonic crystal heterostructure based on coupling of a surface plasmon and a Tamm plasmon mode; the one-dimensional photonic crystal heterostructure is stacked by multiple thin films, and from top to bottom, the one-dimensional photonic crystal heterostructure comprises a metal layer, a dielectric spacer layer, a distributed Bragg reflector (DBR) and a substrate. The application adopts hybridization of two different optical modes, and enhances the interaction between surface light and matter. Compared with the TPP mode and the SPP mode, the hybrid mode solves the problem of large metal loss, and improves the Q value. In the application of the laser, the high Q value characteristic and the Purcell effect of the hybrid mode are utilized, and a four-level gain system is introduced to effectively compensate for the loss, so that the laser threshold is significantly reduced, and the problem of high threshold of the plasmonic laser is solved.

The application belongs to the technical field of laser, and discloses a steady-state simulation method, equipment and storage medium of a solid laser. A pump source model is constructed to calculate pump light intensity and photon flux; a crystal heat source distribution is solved based on the pump light intensity, a three-dimensional temperature field and a thermal lens focal length are obtained by using a step-by-step Fourier solving method; the stability is analyzed by dynamically updating the equivalent g parameter and the curvature radius of the resonant cavity by using the thermal lens focal length; the pump absorption and gain distribution are calculated in combination with the pump light intensity, the photon flux and the crystal boundary reflection characteristics; the pump-laser mode overlap factor is calculated based on the beam parameter calculated according to the equivalent g parameter, the pump light intensity and the laser light intensity; the laser threshold power is calculated, and the output power is calculated in combination with the threshold power and the input pump power; the steady-state laser field is iteratively solved based on the equivalent g parameter, the thermal lens focal length and the gain distribution, and finally the simulation result is output, the dynamic coupling feedback of the thermal lens focal length and the resonant cavity parameter is realized, and the simulation precision is significantly improved.

A threshold magnetometer includes a vertical cavity surface-emitting laser with a first material that is disposed in one of the layers. The first material is configured as an absorbent material or emission material to light propagating in the optical resonator. As an absorbent material, the first material absorbs light when exposed to radio frequency (RF) radiation at one or more resonant frequencies. As an emission material, the first material intensifies light when exposed to RF radiation at one or more resonant frequencies. The resultant intensity change can be detected and used to determine characteristics of an external magnetic field.

The application discloses a preparation method of a near-infrared vertical cavity surface laser with low threshold and high gain based on weakly confined quantum dots, and belongs to the technical field of quantum dot lasers. A CdS shell layer is grown on the weakly confined double-tapered CdSe quantum dots, and the thickness of the CdS shell layer is controlled to be 2 layers by controlling the injection amount of dodecanethiol; the CdSe / CdS quantum dots are spin-coated on the high-reflection surface of two Bragg reflectors (DBRs); and the surfaces coated with the quantum dots are close to each other and are spliced to form a vertical cavity surface laser. The vertical cavity surface laser constructed by taking the weakly confined double-tapered hexahedral CdSe / CdS quantum dots as deep red gain material has deep red / near-infrared laser emission of 720 nm, an extremely low laser threshold of 11.23 µJ / cm 2 and an extremely wide gain bandwidth of 670-730 nm.

The invention discloses an electrically driven perovskite laser and a preparation method thereof, the device takes a perovskite semiconductor or a combination of the perovskite semiconductor and other materials as a main gain medium, and laser emission can be generated under the driving of current or voltage without the assistance of an external light source. The device type comprises an electrically driven integrated (including a single cavity and double cavities) and a non-integrated perovskite laser, and the laser threshold is less than 10000 A / cm < 2 > and can be less than 100 A / cm < 2 > after optimization. In the embodiment, a double-cavity structure is formed by vertically stacking the high-power microcavity perovskite light-emitting diode subunit and the low-threshold microcavity perovskite light amplification subunit, electrically-driven perovskite laser emission is achieved for the first time, the inter-cavity optical coupling efficiency exceeds 80%, the half-peak width of a laser spectrum is about 0.5 nm, and the threshold is as low as 92 A / cm < 2 > and is about 7 times lower than that of an electrically-driven integrated organic laser. The laser can be integrated on a silicon-based substrate, the modulation bandwidth reaches 36.2 MHz or above, the GHz magnitude is expected to be reached after optimization, and the laser has potential application value in the field of communication and calculation.

The invention discloses a control method for generating pulse laser and a pulse laser. The control method comprises the following steps: continuously pumping a gain medium; in the inversion population accumulation process in the gain medium, the linear loss modulator is controlled to work in a first state, the loss of the resonant cavity is reduced to a first loss level through the first state, the pulse laser is driven by the first loss level to enter and undergo a relaxation oscillation process, and the inversion population is stabilized to a steady-state value; the steady-state value corresponds to a laser threshold value under the first loss level; and after the reversal particle number reaches a steady-state value, the linear loss modulator is controlled to be switched to a second state, the loss of the resonant cavity is reduced to a second loss level by the second state, and the resonant cavity is driven to emit pulse laser by the second loss level. According to the invention, relaxation oscillation is introduced into a laser generation process through active guidance of the linear loss modulator, and time domain noise is suppressed, so that a pulse with high peak power and high energy stability is formed.

The application discloses a polymer cholesteric liquid crystal laser and a preparation method and optical equipment thereof. The polymer cholesteric liquid crystal laser comprises a laser main body, the laser main body comprises a light-transmitting conductive substrate, a polymer cholesteric liquid crystal layer, a noble metal reflection layer and a resonant cavity unit; the light-transmitting conductive substrate is provided with a parallel orientation layer; the polymer cholesteric liquid crystal layer is arranged on the surface of the parallel orientation layer; the noble metal reflection layer is arranged opposite to the polymer cholesteric liquid crystal layer; the resonant cavity unit is arranged between the noble metal reflection layer and the polymer cholesteric liquid crystal layer; the resonant cavity unit is filled with a planar light waveguide; the planar light waveguide comprises a perovskite quantum dot layer and a transparent separation layer; the transparent separation layer is arranged on the perovskite quantum dot layer and faces two surfaces of the polymer cholesteric liquid crystal layer and the noble metal reflection layer. Through the above structural design, the polymer cholesteric liquid crystal laser has low laser threshold, high radiation intensity and good repeatability.

This invention proposes a semiconductor laser with a biexciton quantum confinement layer, comprising, from bottom to top, a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, an electron blocking layer, and an upper confinement layer. The lower waveguide layer, the active layer, and the upper waveguide layer constitute the biexciton quantum confinement layer. The thickness of the well layer in the active layer is greater than the thickness of the barrier layer. The Si doping concentration and In content of the biexciton quantum confinement layer both reach their peak values ​​in the active layer. This invention can reduce In segregation in the active layer, improve In composition fluctuations, reduce valence band junction, enhance hole injection and hole transport efficiency, make the electron wavefunction amplitude of the active layer smaller than the Bohr exciton radius, limit low refractive index dispersion, generate quantum confinement effect and biexciton optical gain, enhance quantum state splitting and suppress Auger decay, enhance biexciton emission efficiency, thereby reducing the laser threshold, extending the laser gain lifetime, and increasing laser power.

The application relates to a GaN thick film growth method for improving laser stripping efficiency. The method comprises the following steps: (1) adopting an oxalic acid solution to perform etching on a sapphire substrate with GaN seeds, and forming uniform nanometer-sized hollows; (2) introducing ammonia gas, and heating to a GaN thick film growth temperature under the protection of the ammonia gas; (3) growing a GaN thick film on the sapphire substrate with the GaN seeds through a metal organic chemical vapor deposition method or a hydride vapor phase epitaxy method, bonding the GaN thick film to a silicon wafer, stripping the substrate through laser, and obtaining the GaN thick film. The application forms nanometer-sized sponge branch-shaped hollows on the sapphire substrate with the GaN seeds through electrochemical etching, forms weak connection between lattices at the interface, effectively reduces laser threshold energy during laser stripping, significantly improves laser stripping efficiency by 50%, and meanwhile, the GaN thick film which is stripped off has good toughness, high quality and is not easy to be broken, and the qualified rate is significantly improved.

The application discloses a chip active optical clock based on a MEMS atomic gas chamber and an implementation method thereof. The application pumps the gain medium in the MEMS atomic gas chamber by laser, establishes population inversion, and through the cavity feedback of the resonant cavity, continuously amplifies the spontaneous radiation to reach the laser threshold, and then outputs the active lasing signal. Since the resonant cavity for generating the active lasing signal is a bad cavity, the gain line width is much smaller than the cavity mode line width, the noise caused by the cavity dragging effect can be greatly suppressed, and the output laser can be directly used as an optical frequency standard signal without the need of a servo circuit to stabilize the resonant cavity length, thereby reducing the volume and power consumption of the system. Meanwhile, the MEMS atomic gas chamber is used as a core component, various optoelectronic components are assembled in a stacking mode and integrated on a silicon-based chip, and the chip microcavity optical comb is combined to perform frequency down-conversion, so that the chip active optical clock with a narrow line width and high stability is realized. The application provides a new way for the deployment of the active optical clock in miniaturized and portable time-frequency devices.