23 results about "Photon density" patented technology

The invention provides a distributed feedback laser with a double-layer grating structure, and relates to the technical field of lasers, the laser forms an InGaAlAs multi-quantum well active region, an upper sampling grating layer and a lower phase shift grating layer on an n-type InP substrate in sequence, the upper grating layer is designed based on a reconstruction equivalent chirp technology, and the lower phase shift grating layer is designed based on a reconstruction equivalent chirp technology. Two sections of asymmetric modulation areas with sampling periods linearly gradually changing in opposite directions are arranged in the axial direction of the resonant cavity, and the lower grating layer is a quarter-wave phase shift grating matched with the period of the upper seed grating. Through the synergistic effect of equivalent phase modulation and phase shift generated by the double-layer grating, the photon density distribution in the cavity can be improved, the longitudinal space hole burning effect can be weakened, the sensitivity to end face phase fluctuation can be reduced, high single-mode power and large modulation bandwidth can be realized in a wide temperature range, and the double-layer grating is suitable for a high-speed optical communication and coarse wavelength division multiplexing transmission system.

The invention provides a seawater chlorophyll a concentration three-dimensional remote sensing detection method, medium, equipment and product, and relates to the technical field of ocean remote sensing. The method comprises the following steps: acquiring satellite remote sensing data and photon counting laser radar data of a to-be-detected area; obtaining a seawater chlorophyll a concentration profile based on the diffusion attenuation coefficient; the method comprises the following steps: constructing an improved VGGNet model which comprises a multi-branch VGGNet, replacing standard convolution in the VGGNet with depth separable convolution, and introducing an SE attention mechanism into a backbone network; the time and position variables, the satellite remote sensing data, the photon density, the backscattering coefficient, the diffusion attenuation coefficient and the water depth serve as input variables of the model, the seawater chlorophyll a concentration profile serves as a target variable, and the model is trained; and inputting new satellite remote sensing data into the trained model to generate three-dimensional distribution prediction of the seawater chlorophyll a concentration. The method can better extract the features in the data, improves the prediction precision of the model, and is suitable for a complex water body environment.

The invention relates to a quantum cascade laser with a cylindrical waveguide and a preparation method thereof, and belongs to the field of photoelectron, the quantum cascade laser comprises a laminated structure, the laminated structure is provided with two waveguide grooves, a ridge waveguide is formed between the two waveguide grooves, the waveguide grooves are hyperbolic, and the ridge waveguide is cylindrical; the bottom and side wall areas of the waveguide groove are subjected to mechanochemical grinding treatment and filled with InP: Fe, then mechanochemical grinding is carried out again, and then an insulating film layer material is evaporated; due to the unique cylindrical shape of the ridge waveguide, the photon density can be effectively improved, and the output characteristic of laser is optimized; and meanwhile, the mode distribution of light can be better controlled, and excellent laser characteristics are realized by utilizing optical reflection and interference effects. According to the invention, before secondary epitaxy, a mechanochemical grinding method is adopted to carry out surface treatment on the double channels, so that waveguide loss after secondary epitaxy of InP: Fe can be effectively reduced, the threshold current density is further reduced, and the output power and the slope efficiency are increased.

The invention provides a P-SCH layer, a CW laser epitaxial structure and a preparation method of the P-SCH layer and the CW laser epitaxial structure, and belongs to the field of semiconductors. The invention provides a P-SCH layer which is of a multi-layer structure, the number of layers of the multi-layer structure is 2n, n is larger than or equal to 2, and the emission wavelength is gradually increased from the first layer to the 2n layer; the difference between the emission wavelength of the (n + 1) th layer and the emission wavelength of the nth layer is 100-120nm, and the difference between the emission wavelengths of the other adjacent layers is 10-20nm. According to the invention, the stepped structure with small emission wavelength span at two ends and large middle span between layers ensures the electron leakage rate and the hole injection rate to a great extent, thereby controlling the increase rate of the photon density along with current injection, and improving the temperature stability of the device.

The application discloses a camera design optimization method based on single-photon density imaging, which relies on a single-photon avalanche diode (SPAD) device to capture incident photon information, and then constructs a photon cube for representing the light detection condition at each pixel point and the characteristic information of the photons. The arrival of the photons can be modeled as a Poisson process, the time contrast projection technology is adopted to generate photon events, and the exponential response curve is used to avoid underflow, the sensitivity under low light conditions is improved by optimizing the event triggering mechanism, and the imaging performance is optimized. The application achieves the imaging effect through the photon cube information collected by the SPAD and the corresponding algorithm. And through the optimization of the algorithm, higher video reconstruction quality and lower bandwidth cost are realized, and the application has good practical value.

The invention relates to the technical field of optical fiber lasers, in particular to a miniaturized high-power narrow-linewidth optical fiber laser and a transmitting method.The laser comprises a single-frequency semiconductor laser, an optical fiber circulator, a first beam splitter, an optical fiber pre-amplifier, a second beam splitter, an optical fiber attenuator, an isolation band-pass filter and an optical fiber main amplifier; the first beam splitter is used for splitting the single-frequency laser, and the optical fiber pre-amplifier is used for performing power pre-amplification to obtain a pre-amplified optical signal; the second beam splitter is used for splitting the pre-amplified optical signal; the optical fiber attenuator is used for adjusting the carrier density and the photon density of the single-frequency semiconductor laser which are disturbed by the optical power fed back to the single-frequency semiconductor laser to induce a chaotic state, broadening the output spectrum of the semiconductor laser, and realizing effective suppression of stimulated Brillouin scattering in a power amplification process. According to the invention, a spectrum regulation and control mode with a simple structure is adopted, stimulated Brillouin scattering in a power amplification process can be inhibited, and high-power narrow-linewidth fiber laser output is realized.

The application relates to the technical field of semiconductor device special equipment manufacturing, and discloses a micro-order regulation method and system based on a metastable energy window. The method emits a pulse photon beam with a specific frequency to the surface of a semiconductor target material, so that lattice atoms enter a metastable energy window; the reflection spectrum of the semiconductor target material is collected in real time during the pulse intermittent period, and lattice vibration mode features are extracted; the lattice vibration mode features are compared with preset metastable energy window boundary threshold values, the photon density and the duration of the next pulse photon beam are dynamically adjusted according to the comparison result, and lattice atoms are repaired by short-range atomic rearrangement in the metastable energy window. The scheme limits energy injection to the metastable interval, and blocks the long-range diffusion path of doped atoms.

The invention discloses a distributed feedback laser based on an asymmetric sampling grating and a manufacturing method thereof, and belongs to the technical field of laser, in a grating structure of the laser, the position of equivalent pi phase shift deviates from the center of a cavity, and the duty ratio of the sampling grating, namely the ratio of the length of a sampling window to a sampling period, is less than 0.5. According to the invention, the reconstruction equivalent chirp technology is adopted, and the design of asymmetric phase shift and asymmetric coupling coefficient is combined, so that the forward output power is remarkably improved. In the structure of the laser, asymmetric regulation and control of photon density distribution are realized by optimizing the phase shift position and the duty ratio of the sampling grating, so that the forward output power is improved on the premise of keeping the stability of a single longitudinal mode. According to the method, the sampling structure is prepared by adopting a micron-sized photoetching technology, so that the dependence on high-precision electron beam photoetching is reduced, and the manufacturing tolerance and the cost effectiveness are improved. Experimental results show that the laser is stable in spectrum when working at the C wave band, and the side mode rejection ratio is higher than 50 dB.

The invention provides a directly modulated laser, which comprises a substrate, an epitaxial layer, a buffer layer, a grating layer, a lower limiting layer, an active layer, an upper limiting layer, a corrosion cut-off layer, a cladding and a contact layer, the structure of the grating layer is a convex grating structure with a lambda / 8 phase shift, the grating layer is located on the N-type doped side, and the convex grating structure with the lambda / 8 phase shift is used for reducing the photon density at the phase shift position through the negative reflector loss feedback effect and limiting hole gathering on the P-type doped side through the characteristic that the electron mobility is larger than the hole mobility.

The invention relates to the technical field of photoelectrons, and discloses a distributed feedback laser and a preparation method thereof, and the distributed feedback laser comprises a substrate layer, a separation limiting heterostructure, a coupling grating layer, a dielectric layer, an anode and a cathode. Bragg gratings are sectionally arranged on the side wall of the ridge waveguide of the coupling grating layer along the cavity length, each grating at least comprises two grating sections with different coupling coefficients, and a quarter-wavelength phase shift region is arranged at the center of the cavity; the end face of the cavity can adopt an anti-reflection or high-reflection coating film combination. The coupling coefficient and length ratio of each section is determined according to the end face reflectivity, target coupling coefficient distribution is achieved by changing parameters such as the side wall etching depth, the uniformity of photon density distributed along the cavity length is improved, the longitudinal space hole burning effect is restrained, and narrower line width is achieved while single longitudinal mode output is kept; the distributed feedback laser is simple in structural technological process, low in requirement for mask and etching precision and suitable for narrow-linewidth light sources with different cavity lengths and end face reflection conditions.

The application discloses a kind of external cavity VCSEL laser array mutual injection dynamics modeling simulation methods, comprising: setting up the structure parameters of external cavity VCSEL laser array with multiple high-order transverse mode and the working condition of driving external cavity VCSEL laser array normal operation;Based on L-K rate equation model, the dynamics model of external cavity VCSEL laser array mutual injection is established, and the partial differential equation set that carrier density, photon density and phase are related to space and time is constructed;The partial differential equation set is reduced, and the partial differential equation set is converted into only time variable ordinary differential equation set;The ordinary differential equation set is discretized, and numerical solution is calculated using finite difference method;The variation image of carrier density, photon density, phase and wavelength with time is output.The application can analyze the dynamics process of external cavity mutual injection of VCSEL array with multiple high-order transverse mode output, and find the condition that can realize coherent phase locking.

The invention discloses a camera design optimization method based on single photon density imaging, and the method comprises the steps: capturing incident photon information through a single photon avalanche diode (SPAD) device, and constructing a photon cube for representing the light detection condition at each pixel point and the feature information of photons. The arrival of photons can be modeled as a Poisson process, a time contrast projection technology is adopted to generate a photon event, an index response curve is utilized to avoid underflow, and an event triggering mechanism is optimized, so that the sensitivity under a low light condition is improved, and the optimization of imaging performance is realized. According to the invention, the imaging effect is achieved through the photonic cube information collected by the SPAD and a corresponding algorithm. And higher video reconstruction quality and lower bandwidth cost are realized through optimization of the algorithm, and the method has better practical value.

This invention provides a method for preparing amorphous photonic crystal microspheres and their applications, relating to the field of biomedical optical engineering technology. Based on droplet confinement assembly technology and microfluidic droplet assembly, this invention provides a method for preparing amorphous photonic microspheres. The inverse opal-structured PLGA amorphous photonic crystal microspheres prepared using this method can focus and scatter NIR irradiation. Through micro- and nano-structures, the intensity, spectrum, polarization, and radiation of light can be controlled, producing angle-independent coherent scattering of photons at specific frequencies, thereby localizing photon propagation, enhancing local photon density, and providing a beneficial effect on cognitive function. The inverse opal-structured PLGA amorphous photonic crystal microspheres prepared by this invention effectively improve the photobiological efficacy and bioavailability of near-infrared photobiology, achieving precise control of organisms by manipulating near-infrared light using optical materials.

This invention provides a method for easily and accurately calculating the wet weight of seaweed. [Solution] The estimation method is a method for estimating the growth index of an object that grows in water by photosynthesis, comprising the steps of: measuring the photon density near the object during or after growth; and estimating the growth index of the object during or after growth based on the measured photon density and information showing the relationship between the photon density and the growth index.

Provided is a method for easily and highly accurately calculating the wet weight of seaweed. This estimation method is used for estimating a growth index of an object growing in water through photosynthesis, the method comprising: a step for measuring the photon density in the vicinity of the object during or after growth; and a step for estimating a growth index of the object during or after growth on the basis of the measured photon density and information indicating the relationship between the photon density and the growth index.

The invention relates to a semiconductor laser structure capable of reducing a hole burning effect, which comprises a lower electrode layer, a substrate layer, a lower cover layer, a lower waveguide layer, a multi-quantum well layer, an upper waveguide layer, an upper cover layer, a ridge layer, a graphical contact layer and an upper electrode layer which are sequentially stacked from bottom to top, the graphical contact layer is formed by alternately arranging a plurality of contact strips and a plurality of insulating strips at intervals, the sizes of the contact strips in the arrangement direction are gradually increased from the contact strip in the middle to the contact strips at the two ends in the arrangement direction, and the sizes of the insulating strips in the arrangement direction are equal. According to the semiconductor laser structure capable of reducing the hole burning effect, the patterned contact layer is utilized to form a non-uniform grid structure, current injection is customized for the upper electrode layer and the lower electrode layer through non-uniform grids, the hole burning effect caused by heat accumulation in the center area of the semiconductor laser structure and high photon density is reduced, and finally the stability of the laser is improved; leakage current is further reduced, high-temperature characteristics are improved, and reliability is improved.

The invention relates to an on-orbit fine denoising and grading method for single-photon laser data. The method comprises the following steps: constructing a surface type database; segmenting the laser point cloud data at equal intervals in the along-rail scanning direction; fitting the photon density distribution characteristics of the laser point cloud data segmented in the previous step; calculating a photon grading threshold according to a fitting result, and judging the confidence grade of photons; and performing photon fine denoising and grading on each section of laser point cloud data based on the photon grading threshold. According to the satellite-borne single-photon laser point cloud data on-orbit fine denoising and confidence grading method, on-orbit fine denoising and confidence grading of satellite-borne single-photon laser point cloud data are achieved, photon fine denoising point cloud products are rapidly provided for users, and data input is provided for satellite-borne subsequent point cloud advanced product generation.

Device for detecting and controlling high-temperature corrosion of a wall-like cut-circle boiler based on real-time CO measurement, characterized in that it comprises a hollow tube (10) wherein a CO content detection arrangement is provided in the hollow tube (10), and wherein the hollow tube (10) is connected to a vacuum extraction system and a gas extraction system;wherein the CO content detection arrangement comprises a light source (41), a detector (44) and a first cylinder (60), wherein the light source (41) is provided in the upper part inside the hollow tube (10), wherein the light source (41) is provided with a monochromator (42) and a photon emitter (51), and wherein the detector (44) is provided in the lower part inside the hollow tube (10), wherein the detector (44) is connected with a photon detector (53) and a data analysis module (45), wherein a first cylinder (60) is provided on the outer wall of the hollow tube (10), wherein the first cylinder (60) is connected to the inner part of the hollow tube (10), and wherein a piston (63) is provided in the first cylinder (60), wherein the piston (63) is connected to a cassette (61), wherein the cassette (61) is provided with a gas cylinder (62), and wherein the first cylinder (60) is used to hold the chemiluminescent reagent.;

An apparatus for measuring photon density, the apparatus comprising a substrate having a volume for receiving photons from within an optical radiation field, the substrate having an outer periphery, an inner periphery, and an exit aperture, a first reflecting layer coating at least a portion of the outer periphery of the substrate, the first reflective layer configured to integrate the photons within the volume of the substrate, a plurality of entrance openings within the first reflective layer for diffracting the photons entering the volume and a photon detector configured to receive the photons to detect a photon density and to produce an electrical signal representative of the detected photon density, wherein the substrate having the coating is configured such that the photons incident on the exit aperture of the volume of the substrate are at least substantially equally proportional to the photons incident on the plurality of entrance openings.

The application discloses a kind of dual-wavelength lasers, solve the technical problems that existing dual-wavelength lasers are unstable in power, or system is complex, bulky, or conversion efficiency is low, easily influenced by outside.This application uses semiconductor gain chip as gain medium, optical resonant cavity and optical filter as mode selector, realize controllable dual-wavelength laser output of frequency interval, adopt external cavity structure to obtain lower intracavity noise photon density;Optical resonant cavity used has very narrow filter bandwidth, can avoid mode competition problem, ensure the stable output of dual-wavelength laser;While generating dual-wavelength output, the four-wave mixing nonlinear effect in optical resonant cavity is utilized, and the phase noise and frequency stability of dual-wavelength beat signal are improved.

The application provides a P-SCH layer, a CW laser epitaxial structure and a preparation method thereof, and belongs to the field of semiconductors. The application provides a P-SCH layer, which is a multilayer structure, the number of layers of the multilayer structure is 2n, n is greater than or equal to 2, the emission wavelength increases from the first layer to the 2n layer; the difference between the emission wavelength of the n+1 layer and the emission wavelength of the n layer is 100-120 nm, and the difference between the emission wavelength of the remaining adjacent layers is 10-20 nm. The layer has a small span of two end emission wavelengths and a large span of middle emission wavelengths, a ladder structure, which greatly guarantees the electron leakage rate and the hole injection rate, thereby controlling the increase rate of the photon density with the increase of the current injection, and improving the device temperature stability.

Active hybrid silicon optical device structures including a silicon optical waveguide and a III-V semiconductor material stack further includes a high refractive index spacer located between the silicon waveguide and a III-V gain material. The spacer may be undoped or doped (e.g., n-type). The spacer may have a composition unique from the III-V semiconductor material stack or the spacer may have substantially the same composition as one or more other material layers of the III-V semiconductor stack. In exemplary embodiments, the spacer has a refractive index of at least 3.0 and a layer thickness of at least 0.3 μm. In laser structures, the spacer locates peak power of the resonant mode farther from the optical gain material and / or doped material having high optical loss. Along with reducing modal losses, mode area is increased, reducing photon density and improving laser reliability. In SOA structures, greater mode area may increase saturation power.