63 results about "Light absorption coefficient" patented technology

The invention belongs to the technical field of deep learning, particularly relates to a two-stage blind image defogging method based on prior guide diffusion, and aims to solve the problem of distortion of a traditional decontamination method in a complex scene. Comprising the steps that a double-stage blind image defogging model is constructed, and the double-stage blind image defogging model comprises a first stage and a second stage; wherein in the first stage, physical modeling is carried out based on an improved atmospheric scattering model, the improved atmospheric scattering model is an enhanced atmospheric scattering model in which a light absorption coefficient is introduced, and a transmission image, a fogless reference image and atmospheric light parameters are output through the first stage; in the second stage, generation optimization is carried out based on a diffusion model, the transmission image, the fog-free reference image and the atmospheric light parameters output in the first stage are used as physical priori to be fused into the generation process of the diffusion model, and image defogging is carried out. In the second stage, self-adaptive difference fusion convolution is set, a fog domain multi-source fusion attention mechanism is set, and a pixel level and wavelet domain double-effect color correction strategy is adopted.

The embodiment of the invention relates to the field of photomasks, and provides a photomask protective film frame and a preparation method thereof, the photomask protective film frame comprises a frame main body made of a metal material and a coating formed on the surface of the frame main body, and the photomask protective film frame is characterized in that the coating is at least composed of carbon black, silicon dioxide particles and organic dye. The nanoscale carbon black in the coating has a high light absorption coefficient, fills gaps of dye molecules and forms a continuous light absorption network, the organic dye enhances absorption of light with specific wavelength through a molecular structure conjugated system, and the nanoscale carbon black and the organic dye form a composite function of broad-spectrum absorption and accurate waveband adjustment, so that more than 95% of light is absorbed in a broad-waveband range, light reflection on the surface of the frame is reduced, and the light absorption efficiency is improved. Pattern distortion caused by reflected light in the photoetching process is avoided, silicon dioxide is embedded into an organic dye matrix, silicon dioxide gaps are filled with carbon black particles, the porosity of the coating is reduced, the wear resistance of the coating is improved, and the cracking risk of the coating is reduced. Optical absorption, wear resistance and weather resistance are synchronously improved.

The invention discloses a TopCon cell and a TopCon cell preparation method, and belongs to the field of solar cells. The structure of the passivation layer is optimized, the doped polycrystalline silicon layer is reserved in the metal contact area, the doped polycrystalline silicon layer and the substrate form a high-low junction to provide field passivation, and ohmic contact is formed between the doped polycrystalline silicon layer and the electrode; a doped polycrystalline silicon carbide layer is arranged in a non-metal contact area, and the doped polycrystalline silicon carbide layer and a substrate form a heterojunction to provide field passivation and serve as a carrier transverse transmission layer. The parasitic absorption of the passivation layer is reduced by removing the doped polycrystalline silicon layer in the non-metal contact region. The light absorption coefficient of the doped polycrystalline silicon carbide layer is low and the doped polycrystalline silicon carbide layer is thin, so that parasitic absorption can be reduced. Ohmic contact is formed between the doped polycrystalline silicon layer in the reserved metal contact area and the electrode, so that low recombination loss can be ensured when the doped polycrystalline silicon layer is in contact with the metal grid line. Field passivation is formed in the metal contact area and the non-metal area, and the passivation effect of the whole surface of the substrate is guaranteed.

The utility model relates to the technical field of semiconductor photoelectronics, and provides a white light package adopting a blue-green double-peak single crystal chip, which comprises a package structure and an LED chip arranged in the package structure. The LED chip comprises a substrate, a blue-green double-peak single crystal chip and a red light conversion layer which are sequentially stacked from bottom to top, the blue-green double-peak single crystal chip comprises an electroluminescent blue light quantum well layer and a photoluminescent green light conversion layer, and the red light conversion layer comprises a red light wavelength conversion material containing perovskite quantum dots. A red light wavelength conversion material containing perovskite quantum dots is arranged in the red light conversion layer, the light absorption coefficient of the perovskite material is 105cm <-1 > magnitude, a backlight source with an extremely high display color gamut can be obtained, the color gamut can reach more than 100% of NTSC, the color gamut is far larger than the color gamut which can be achieved by a traditional red light fluorescent powder layer, and the display color gamut of the LED chip is further improved.

The invention relates to the field of environmental protection monitoring, in particular to a method for estimating secondary organic carbon concentration, which comprises the following steps: (A1) acquiring OC and EC in atmospheric particulates in a first period T1; meanwhile, light absorption coefficients bs and BC of a plurality of wavelengths lambda s in a second period T2 are obtained; (A2) obtaining BC1 and BC2 according to the light absorption coefficient bs; (A3) obtaining a minimum value A of m OC / (BC2. EC); (A4) a is progressively increased from 0 to A according to the step length d, and ci corresponds to ai; (A5) for each array (ai, ci), calculating a correlation coefficient ri corresponding to m groups of BC / EC and OC / (ai. BC1. EC + ci. BC2. EC), and corresponding to the array (aj, cj) when the ri is maximum; and (A6) secondary organic carbon concentration SOC = OC-cj * BC2 * EC-aj * BC1 * EC. The method has the advantages of accurate estimation and the like, and is applied to environmental protection monitoring.

The invention relates to the technical field of semiconductor photoelectric devices, and discloses a GeSe / Si heterojunction photoelectric device and a preparation method thereof, the GeSe / Si heterojunction photoelectric device comprises a bottom electrode, an n-type silicon substrate, a GeSe layer and a top electrode; wherein the n-type silicon substrate and the GeSe layer form a Van der Waals heterojunction, the whole GeSe / Si heterojunction photoelectric device is of a sandwich structure, the bottom electrode is in contact connection with the n-type silicon substrate, and the top electrode is in contact connection with the GeSe layer. The GeSe / Si Van der Waals heterojunction-based high-performance photoelectric device with a sandwich structure and an II-type energy band structure is designed and prepared, due to the light transmission of the Au / ITO top electrode, GeSe with a high light absorption coefficient is used as a light absorption layer, a large number of photon-generated carriers can be generated, and the photoelectric device can be applied to the field of photoelectric devices. A built-in electric field and an II-type energy band structure of the GeSe / Si heterojunction can quickly separate photon-generated carriers to form light current, so that high responsivity of 29.8 A / W, high quantum efficiency of 6959.7% and quick light response time of 8.5 / 23.7 us are realized.

The application discloses a kind of bromine iodine lead cesium perovskite solar cells of doping magnesium bromide prepared in low humidity environment and preparation method thereof, belong to perovskite photovoltaic technical field, including ITO transparent conductive glass and sequentially coated on ITO transparent conductive glass dense layer TiO2, SnO2 layer, bromine iodine lead cesium perovskite light-absorbing layer of doping magnesium bromide, 2,2',7,7'-tetra [N,N-di (4-methoxyphenyl) amino] -9,9'-spirobifluorene hole transport layer of doping lithium salt, silver electrode, and its preparation method is disclosed, the application is by doping into bromine iodine lead cesium perovskite precursor doping different molar magnesium bromide to optimize the energy level matching between perovskite and electron transport layer and hole transport layer, effectively reduce the recombination probability of carrier and improve the mobility of carrier, improve the crystal quality of perovskite thin film, to realize the light absorption coefficient of optimization light-absorbing layer, finally realize the improvement of bromine iodine lead cesium inorganic perovskite solar cell photoelectric conversion efficiency.

To provide a see-through solar cell module with high visibility.SOLUTION: A solar cell module manufacturing method according to an embodiment of the present invention includes the steps of laminating a first transparent electrode layer on a transparent substrate, forming a first separation groove extending in a first direction by irradiating with a laser, laminating a first semiconductor layer, a photoelectric conversion layer, and a second semiconductor layer, forming a second separation groove extending in the first direction by irradiating with a laser, laminating a second transparent electrode layer, forming a third separation groove extending in the first direction by irradiating with a laser, and removing the layer and lifting off layers laminated on the first layer by irradiating with a laser having a wavelength such that the optical absorption coefficient of the portion of the first transparent electrode layer on the first semiconductor layer side or at least the portion of the first semiconductor layer in contact with the first transparent electrode layer is greater than the optical absorption coefficient of the photoelectric conversion layer, thereby forming a light-transmitting groove extending in a second direction intersecting the first direction.SELECTED DRAWING: Figure 4

The application provides a glass material, wherein a cation component contains, in terms of mole percentage, Si 4+ : 4-16%; B 3+ : 45-70%; La 3+ : 3-18%; Ca 2+ : 2-20%; and an anion component contains F ‑ : 1-15%; O 2‑ : 85-99%. Through reasonable component design, the glass material has high refractive index and low light absorption coefficient, and meets the application in the fields of image transmission optical fibers and the like.

The invention relates to an opto-acoustic-ultrasonic multi-mode bone metabolism and senescence noninvasive detection method and device, and the method comprises the following steps: respectively collecting an ultrasonic signal and a multi-wavelength opto-acoustic signal in a detection period; calculating the ultrasonic sound velocity and the broadband ultrasonic attenuation coefficient of the to-be-detected bone based on the ultrasonic signal, comparing the ultrasonic sound velocity and the broadband ultrasonic attenuation coefficient with the data of the healthy bone, and preliminarily judging the health degree of bone metabolism; based on the ultrasonic sound velocity and the broadband ultrasonic attenuation coefficient of the to-be-detected bone, performing ultrasonic attenuation compensation on a bone tissue part in the photoacoustic signal; fitting the opto-acoustic signal subjected to ultrasonic attenuation compensation corresponding to each wavelength into a transmission equation of a macroscopic homogeneous medium, calculating to obtain a relative light absorption coefficient of each wavelength, and mapping the relative light absorption coefficient and the corresponding wavelength to obtain a relative light absorption spectrum of the to-be-detected skeleton; and performing linear fitting on the relative light absorption spectrum and the main component spectrum in the skeleton, decoupling related photoacoustic parameters of the chemical component content, and further judging the skeleton metabolism and aging degree. Compared with the prior art, the method has the advantages of being low in detection complexity, non-invasive, non-radiative, capable of comprehensively obtaining physical microstructures and biochemical information related to bone metabolism and aging and the like.

The invention discloses a multi-dimensional element and physical constraint fused atmospheric black carbon source analysis method and system, and the method comprises the steps: obtaining a ratio of BC total mass concentration to a primary light absorption coefficient, and calculating a primary BC light absorption coefficient according to the BC total mass concentration and the ratio; carrying out pretreatment on the primary BC light absorption coefficient; sending the preprocessed primary BC light absorption coefficient and the obtained environmental data into a pre-trained neural network model to obtain light absorption coefficients, BC total mass concentration and BC mass concentration discharged by each discharge source under different wavebands output by the neural network model; when the neural network model is constructed, an activation function and a loss function are defined, and training is completed. The method is based on the atmospheric environment data, combines the physical process of atmospheric BC quality and light absorption coefficient change, overcomes the defect that a traditional neural network model lacks physical significance, and is suitable for BC source analysis tasks in different regions and different atmospheric environments.

This invention relates to the field of graphene quantum dot film technology, and discloses a graphene quantum dot film, its preparation method, and its applications. The film is composed of the following components: modified graphene quantum dots, inorganic nanoparticles, a polymer matrix, a dispersant, a crosslinking agent, and additives. Through the optimized integration of raw material design and preparation process, the graphene quantum dot film of this invention achieves a synergistic improvement in both microstructure and macroscopic performance. From a macroscopic perspective, the film's transmittance reaches a maximum of 91.3% at 550 nm, and its light absorption coefficient reaches 4.0 × 10⁻⁶. 4 cm ‑1 The material exhibits a maximum tensile strength of 48.6 MPa and an elongation at break of 4.5%, and maintains a high performance retention rate even after humid heat and ultraviolet light aging. These superior properties are attributed to the synergistic effect of modified graphene quantum dots, modified inorganic nanoparticles, and optimized polymer matrices, as well as the regulation of processes such as segmented ultrasonication-intermittent stirring and gradient curing.

The invention relates to a sparse regularization photoacoustic imaging de-mixing method and system based on end member automatic extraction. The method comprises the following steps: collecting a multi-wavelength photoacoustic signal and reconstructing a photoacoustic image; based on the photoacoustic image, searching a pixel which enables a convex hull to expand continuously through orthogonal projection, extracting an end member in the photoacoustic image, and performing smoothing processing to obtain an end member curve; and taking the extracted end member curve as priori knowledge, introducing sparse regularization constraint into a target function of photoacoustic imaging unmixing, and solving abundance distribution of each component in the biological tissue by minimizing the target function to obtain an unmixing result. Compared with the prior art, the method has the advantages that the light absorption coefficient of each substance does not need to be obtained as priori knowledge, and the over-fitting resistance is high.

An object of the present application is to provide an organic EL element having a capping layer composed of a material having the following properties: (1) high light absorption coefficient, (2) high refractive index, (3) good stability of thin film, (4) excellent durability, (5) excellent light resistance, and (6) no absorption in the respective wavelength regions of blue, green, and red. Since the arylamine-based material having a specific structure of the present application is excellent in stability of thin film and durability, an amine compound having a specific benzoxazole ring structure and a high refractive index is selected as a material constituting the capping layer, and an organic EL element using the material having a high absorbance at a wavelength of 400 nm to 410 nm in an absorption spectrum at a concentration of 10 ‑5 mol / L shows good element characteristics.

The invention discloses a remote sensing estimation method and a remote sensing estimation device for the primary productivity of marine phytoplankton in size fraction, and the method comprises the steps: building an estimation function of the photosynthetic quantum yield of the phytoplankton in the corresponding size fraction based on the relation between the light intensity and the photosynthetic quantum yield of the phytoplankton in the single size fraction; calculating the net primary productivity of the phytoplankton of the corresponding size fraction based on the photosynthetic quantum yield and the average light absorption coefficient of the phytoplankton of the single size fraction under the scale of the light intensity duration and the ocean depth measurement range; and adding the net primary productivity of the phytoplankton in the plurality of size fractions, and calculating to obtain the total primary productivity of the phytoplankton. By adopting the technical scheme, in a framework of light absorption and conversion of the phytoplankton, the light absorption coefficient of the phytoplankton with different size fractions and the size fraction difference of the photosynthetic quantum yield are considered at the same time, an effective scheme for quantitative expression estimation of the phytoplankton is established, the estimation error of the primary productivity caused by neglecting the size fraction difference can be effectively reduced, and the estimation accuracy of the primary productivity is improved. And the estimation accuracy is improved.

The invention relates to the technical field of security check, and discloses an integrated system based on radioactive substance detection and X-ray radiation imaging. The system comprises an initial modeling module, a detection planning module, a signal acquisition module, a data fusion module, a collaborative analysis module and a comprehensive judgment module. The initial modeling module establishes a synchronous initial space model, the detection planning module generates a key detection subspace according to historical attenuation probability distribution of radioactive substances, the signal acquisition module captures radioactive signals and extracts an X-ray density image, and the data fusion module aligns two types of data time sequences and peels off independent signal streams. The collaborative analysis module identifies suspected core points and calculates X-ray absorption coefficient abnormal fluctuation, and the comprehensive judgment module obtains a judgment result. The system can improve the radioactive signal capturing efficiency, avoid signal interference and enhance the accuracy of radioactive substance judgment, and is suitable for the field of radioactive substance detection.

The application discloses a three-dimensional trench silicon electrode detector and a preparation method thereof. The detector is composed of a plurality of detection units. The detection unit comprises a silicon dioxide protective layer, an outer electrode arranged on the silicon dioxide protective layer, a silicon base and a center electrode arranged on the silicon dioxide protective layer and in the outer electrode. The silicon base comprises a base part and a nested part. The nested part is embedded in the outer electrode and located on the base part. The center electrode and the nested part are filled with an insulator between the center electrode and the outer electrode and between the nested part and the outer electrode. An electrode contact aluminum layer is arranged on the top of the outer electrode, the center electrode and the insulator. An electrode contact port is arranged on the electrode contact aluminum layer of the outer electrode and the center electrode. The application solves the problem that the existing detector has a small light absorption coefficient, a narrow absorption spectrum and cannot fully absorb and utilize solar energy.

The present application provides a silicon substrate, comprising a first surface and a second surface which are opposite to each other. A plurality of recesses are formed in the first surface. The thickness of the silicon substrate is h1, and the depth of the recesses is h2, wherein the difference Δh between h1 and h2 satisfies h1>Δh≥1 / A(λ=300 nm), wherein A(λ=300 nm) is an optical absorption coefficient of the silicon substrate at a wavelength λ=300 nm, with a unit of cm-1. The present application further provides a solar cell and photovoltaic module comprising the silicon substrate. By forming the recesses and establishing a relationship among the depth of the recesses, the thickness of the silicon substrate, and the optical absorption coefficient of the silicon substrate at a corresponding wavelength, absorption of oblique incident light by the recesses is enhanced, and the requirements for specific wavelength response are met.

A puncture path planning method and planning system. The puncture path planning method comprises: constructing a three-dimensional model from a medical image; defining organs and tissue as units having not completely identical light absorption degrees, and assigning light absorption coefficients to the units on the basis of whether a biopsy needle is allowed to pass through and the risk level of puncture; and setting a light source in a puncture target region, obtaining grayscale information on the skin surface by means of analysis of light absorption degrees along different paths, and using the grayscale information to feed back a recommendation degree for each puncture starting point. By converting the selection of a puncture path into the problem of finding an optimal puncture starting point, in combination with a light propagation principle, the novel puncture path planning method and planning system can intuitively display location information of a preferred puncture starting point and are more comprehensive and reliable.

The present disclosure provides a photoelectric conversion element including a first electrode 3, a second electrode 7, a photoelectric conversion layer 5 between the first electrode 3 and the second electrode 7, and a reflection layer 6 between one of the first electrode 3 and the second electrode 7 and the photoelectric conversion layer 5. The wavelength at which the reflectance of the reflection layer 6 is maximum in the visible region is within the range of wavelengths in which the optical absorption coefficient of the photoelectric conversion layer 5 is ⅕ or more of the maximum optical absorption coefficient in the visible region.

The invention relates to a material photoacoustic spectrum measurement method and device. The method comprises the following specific steps: S1, respectively collecting photoacoustic signal data of a standard solution and a to-be-measured solution under different wavelengths; s2, processing the photoacoustic signal data through a reconstruction algorithm to generate an image, and obtaining photoacoustic signal intensity values I of the standard solution and the to-be-detected solution in each region and each scanned wavelength by using the image; and S3, performing double calibration on the obtained photoacoustic signal intensity values I of the standard solution and the solution to be detected to obtain the relative light absorption coefficient of the solution to be detected. The photoacoustic spectrum measuring method based on the photoacoustic imaging system is rapid, convenient and accurate, system operation is simplified, optical differences of biological tissues and instability of a laser system can be effectively coped with, and therefore the consistency of the photoacoustic spectrum and a real optical absorption spectrum is improved, and the measuring accuracy of the photoacoustic spectrum is improved. Therefore, accurate analysis of molecular components in biological tissues is supported.

The present invention belongs to the technical field of semiconductor devices, and discloses an optical synaptic transistor and a manufacturing method thereof. Using the blend of P3HT and perovskite nanosheets as the semiconductor layer, it can be prepared by a simple solution spin-coating method. Benefiting from the high carrier transport efficiency and high light absorption coefficient of perovskite nanosheets, the single synaptic power consumption of this device is only 0.053 fJ under extremely low operating voltage (-0.0005 V), weak light pulse intensity (0.4 mW cm-2), and short illumination time (20 ms). The synaptic transistor provided by the present invention can achieve low power consumption under weak light conditions.

The invention discloses a method for evaluating the light transmission performance of cement-based materials. The method comprises the following steps: firstly preparing a series of cement-based materials with different light-transmitting aggregate contents and cement-based materials without aggregate, measuring light reflectance and light transmittance by means of an integrating sphere; fitting a linear equation according to the transmittance and the aggregate contents, wherein the intercept of the ordinate is the light transmittance of cement without aggregate; substituting the reflectance and transmittance of the cement into an IAD algorithm to iteratively calculate the light absorption coefficient and the light scattering coefficient of the cement; building a structural model of the cement-based material by means of CT imaging or spherical particle accumulation, simulating the transmission of light in the cement-based medium by means of a Monte Carlo algorithm on the basis of the model, finally representing the light flux distribution in the cement-based material by a three-dimensional matrix containing light flux data information, and evaluating the light transmission performance of the cement-based material by means of the light flux distribution.

A kind of high photosensitivity slurry of pure copper photocuring 3D printing and preparation method thereof.The high photosensitivity slurry of pure copper photocuring 3D printing composition includes pure copper powder, active diluent, photoinitiator and auxiliary agent.The active diluent is acrylate monomer, and the photoinitiator includes two groups, one group is cleavage type alpha-amino ketone and its derivative, and the other group is thioxanthone and its derivative group.The thioxanthone photoinitiator has higher molar extinction coefficient in the ultraviolet light around 360nm-405nm wavelength, can compete with copper powder for ultraviolet light to avoid the high light absorption coefficient of copper powder to reduce the light initiation efficiency.At the same time, after thioxanthone absorbs ultraviolet light, energy transfer occurs with alpha-amino ketone, so that alpha-amino ketone photoinitiator jumps to excited triplet state, indirectly realizes slurry photopolymerization, greatly improves the light initiation efficiency, improves the photosensitivity of slurry, and solves the problem of high ultraviolet absorbance of copper powder.

The polarizing plate of the present application is obtained by laminating a polarizer, a first protective film disposed on one side thereof, a second protective film disposed on the other side, and a release film disposed on the side of the first protective film opposite to the polarizer. The light absorption coefficient A2 of the second protective film for light having a wavelength of 9.4 μm is 1.0 x 10 2 ~ 4.5 x 10 2 / μm. In a cross section of the polarizing plate along the lamination direction, the inclination angle φ of a straight line connecting an end point P1 of the release film on the side opposite to the first protective film in the cut end surface and an end point P2 of the second protective film on the side of the polarizer with respect to the lamination direction is 0.5 ~ 10°.

The invention discloses a three-dimensional composite structure slab laser performance simulation implementation system and method, and belongs to the technical field of solid lasers. The implementation method comprises the steps of obtaining a to-be-simulated target parameter; the target is used for calculating the pump light intensity and the laser light intensity of a specific position so as to calculate the output power of the pump light intensity and the laser light intensity; the pump light intensity, the laser light intensity, the pump light absorption coefficient and the laser gain coefficient of any point on the light beam transmission path are obtained to draw a light power result; and a thermal power result is obtained. The beneficial effects of the invention are that simulation results of related laser structures are provided for optimization and improvement of experimental parameters.

The present disclosure discloses a puncture path planning method and a planning system, that leverages principles from optics and computer rendering. The method rapidly calculates optimal puncture paths to serve as a reference for medical personnel, serving as an auxiliary means for information acquisition in clinical practice. The method includes: constructing a three-dimensional model based on medical images; defining organs and tissues as units with different light absorption degrees; assigning light absorption coefficients to each unit according to whether the biopsy needle is allowed to pass and the puncture risk level; placing a light source on a puncture target region; and obtaining grayscale information on the skin surface by analyzing light absorption along different paths, wherein the grayscale information is used to provide feedback on the recommendation level of each puncture starting point.

The embodiment of the invention relates to an optical module, a preparation method thereof and an optical system. The optical module comprises a first functional substrate, a second functional substrate and an electrolyte layer. The first functional substrate includes a first substrate, a first diffraction grating formed on a first surface of the first substrate, and a first electrochromic layer formed on a second surface of the first substrate opposite to the first surface. The second functional substrate comprises a second substrate, a second diffraction grating formed on the third face of the second substrate and a second electrochromic layer formed on the fourth face, opposite to the third face, of the second substrate, and the second face and the fourth face are arranged at intervals in a face-to-face mode. The electrolyte layer is sandwiched between the first electrochromic layer and the second electrochromic layer to form an electrochemical unit. By applying variable voltage to the electrochemical unit, the effective refractive index of the second diffraction grating and the light absorption coefficient of the electrochemical unit can be changed, and then the coupling angle and the light transmittance of the optical module can be dynamically regulated and controlled.

A preparation method of a guanidine lead halide perovskite single crystal and its application in a photodetector, which relates to a preparation method of a perovskite single crystal and its application. The present invention uses aminoguanidine cation (AG + ) as an organic cation, a new type of perovskite single crystal material with a suitable single crystal optical band gap and a high light absorption coefficient is obtained, and it is used in the field of visible light detection. Method: 1. Prepare a precursor solution; 2. Prepare a perovskite single crystal; 3. Clean, dry and polish. A guanidino lead halide perovskite single crystal is used to prepare a photodetector. The guanidino lead halide perovskite single crystal prepared by the present invention has excellent light absorption performance, high carrier mobility and carrier lifetime, good crystallinity and high humidity and temperature stability, and good detector photoelectric response performance; in terms of preparation technology, the manufacturing cost is low, the production process is simple, the temperature required for cooling and crystallization is low, the energy consumption is low, and the requirements for experimental conditions are low.

The present disclosure relates generally to silicon carbide crystals that can be used in optical applications, and to methods for producing the same. In one form, the composition comprises aluminum doped silicon carbide crystals, the aluminum doped silicon carbide crystals having residual nitrogen and boron impurities. A concentration of aluminum in the silicon carbide crystal is greater than a combined concentration of nitrogen and boron in the silicon carbide crystal, and the silicon carbide crystal has a light absorption coefficient of less than about 0.4 cm-1 at a wavelength in the range of about 400 nm to about 800 nm.