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70 results about "Optical tape" patented technology

Optical tape is a medium for optical storage generally consisting of a long and narrow strip of plastic onto which patterns can be written and from which the patterns can be read back. It shares some technologies with cinema film stock and optical discs, but is compatible with neither. In the 1990s, it was projected that optical tape would be a commonly used, high-capacity, high-speed computer data storage format. At least one working system and several prototypes were developed, but as of 2007, none of these technologies are widely used.

Method and device for hitless tunable optical filtering

The method for filtering an optical signal comprising a plurality of channels lying on a grid of optical frequencies equally spaced by a frequency spacing and occupying an optical bandwidth, comprises: a) operating an optical filter comprising a plurality of resonators each having a respective free spectral range, wherein a first resonator of the plurality is optically coupled to the optical signal and the remaining resonators are optically coupled in series to the first resonator, so that a respective resonance of each one of the plurality of resonators falls within a first frequency band having bandwidth less than or equal to 15 GHz; b) operating the optical filter so as to obtain a separation between any resonance of at least one resonator falling within the optical bandwidth with respect to a resonance of at least another different resonator nearest to the any resonance, the separation being greater than or equal to 150 GHz and no more than 1 THz; c) tuning all the resonators of the optical filter so as to move all respective resonances of the resonators by a respective frequency interval greater than the frequency spacing while maintaining a distance between the any resonance of the at least one resonator with respect to the nearest resonance of the at least another different resonator not less than 150 GHz and no more than 1 THz; and d) operating the optical filter so that a further respective resonance of each one of the plurality of resonators falls within a second frequency band, different from the first frequency band, having bandwidth less than or equal to 15 GHz. A corresponding device for filtering an optical signal is disclosed.
Owner:GOOGLE LLC

Temperature and concentration measuring system and method based on double-optical-comb spectrum technology

The invention provides a temperature and concentration measuring system and method based on a double-optical-comb spectrum technology, and belongs to the technical field of laser absorption spectra. The measuring system comprises two optical frequency combs with the repetition frequency difference smaller than 1 MHz, a 2*2 optical fiber coupler, an optical band-pass filter, a collimator, a low-pass filter, a photoelectric detector, a data acquisition card and the like. The double optical combs are subjected to coupling beam splitting, one path is a measurement light path and is received by thephotoelectric detector after passing through to-be-measured gas and the optical band-pass filter, and the other path is a reference light path and is coupled to the photoelectric detector after passing through the optical band-pass filter. Interference signals generated by the double optical combs on the photoelectric detector are filtered by the low-pass filter and then acquired by the data acquisition card. Fourier transform is carried out on interference signals of measurement and reference light paths to extract absorption spectrum information. Finally, the temperature and the concentration are calculated based on a polychromatic method and a least square method. According to the invention, the precise spectral resolution capability of the optical frequency combs is utilized to realize wavelength-free calibration measurement of temperature and concentration, and the application prospect is wide.
Owner:BEIHANG UNIV

Europium doped bismuth ferrite film, preparation method and application thereof

The invention discloses a europium doped bismuth ferrite film, which comprises a silicon substrate with lanthanum nickelate as the buffer layer and a target material with a composition formula of Bi1-xEuxFeO3 (with x being greater than or equal to 0 and smaller than or equal to 0.07). The target material is deposited on the substrate. The invention also discloses a preparation method of the europium doped bismuth ferrite film. The method consists of: cleaning the substrate, placing the target material and the substrate in a film coating chamber, adjusting the pressure to less than 5*10<-4>Pa, raising the temperature of the substrate to 700DEG C at a speed of 10DEG C per minute; adjusting the sputtering pressure to 10Pa, maintaining the state for 10min under 700DEG C and an oxygen pressure of 10Pa, making adjustment to invert the substrate and rotate the target material in forward direction, keeping a 6cm distance between the substrate and the target material, employing a pulse laser to conduct film deposition for 60min and performing heat preservation for 30min, then conducting cooling at a speed of 20DEG C per minute to 200DEG C, and taking out the product, thus obtaining the europium doped bismuth ferrite film. The preparation method provided by the invention has the advantages of easily controllable reaction process and easily available raw materials. The europium doped bismuth ferrite film has significantly improved crystallization properties and electric leakage properties, and a smaller optical band gap, thus improving the photovoltaic properties of BiFeO3 films. The europium doped bismuth ferrite film has wide application prospects.
Owner:EAST CHINA NORMAL UNIV

Dichroscope based on sandwich-like structure interface and composite material and preparation method of dichroscope

The invention discloses a dichroscope based on a sandwich-like structure interface and a composite material and a preparation method of the dichroscope. A material A with the refractive index greaterthan 1.8 and a material B with the optical band gap greater than 6.0 eV are deposited simultaneously through electron beam evaporation technology to form the composite material to replace a single high-refractive-index material in a conventional dichroscope film to serve as a high-refractive-index film layer H, and a single low-refractive-index material C serves as a low-refractive-index film layer L; and by controlling the deposition rate of the material A, the deposition rate of the material B and the deposition rate of the material C, a transition interface of a sandwich-like structure is formed between the high-refractive-index film layer and the low-refractive-index film layer, and the transition interface structure serves as an A+B gradient material layer and AA+C gradient material layer. According to the dichroscope, the interface of the high-refractive-index film layer and the low-refractive-index film layer is designed to be the transition interface of the sandwich-like structure, and the interface bonding force, the laser damage threshold value and other performance of the dichroscope are improved on the premise that the spectral performance of a film is not affected.
Owner:SHANGHAI INST OF OPTICS & FINE MECHANICS CHINESE ACAD OF SCI

Method and system for measuring optical band gap

The invention provides a method and a system for measuring an optical band gap. The method comprises the steps of measuring a to-be-measured sample by adopting an ellipsometer to obtain an ellipsometric data measured value; performing modeling and fitting calculation on the ellipsometric data, judging whether a fitting value obtained through fitting calculation is close to a measured value or not,if the fitting value obtained through fitting calculation is close to the measured value, performing reverse calculation by utilizing dispersion equation parameters obtained through fitting, and acquiring a chromatic dispersion curve of the refractive index and the extinction coefficient of the to-be-measured sample along with the change of the wavelength; acquiring an absorption coefficient of the to-be-measured sample according to the chromatic dispersion curve and an absorption coefficient formula; and solving the optical band gap of the to-be-measured sample according to the absorption coefficient and a Tauc formula. Since the ellipsometer has the features of being high in measurement precision and no requirement on transparency of the substrate material, the measurement of the optical band gap can be precisely realized, and the applicable range of the optical band gap measurement can be greatly expanded; and the method has good measurement effect on the materials such as thin-film material, non-transparent material, multi-layer or complex film structure material and like on the non-transparent substrate or single-side polished substrate.
Owner:UNIV OF SCI & TECH OF CHINA

A kind of europium-doped bismuth ferrite thin film and its preparation method and application

The invention discloses a europium doped bismuth ferrite film, which comprises a silicon substrate with lanthanum nickelate as the buffer layer and a target material with a composition formula of Bi1-xEuxFeO3 (with x being greater than or equal to 0 and smaller than or equal to 0.07). The target material is deposited on the substrate. The invention also discloses a preparation method of the europium doped bismuth ferrite film. The method consists of: cleaning the substrate, placing the target material and the substrate in a film coating chamber, adjusting the pressure to less than 5*10<-4>Pa, raising the temperature of the substrate to 700DEG C at a speed of 10DEG C per minute; adjusting the sputtering pressure to 10Pa, maintaining the state for 10min under 700DEG C and an oxygen pressure of 10Pa, making adjustment to invert the substrate and rotate the target material in forward direction, keeping a 6cm distance between the substrate and the target material, employing a pulse laser to conduct film deposition for 60min and performing heat preservation for 30min, then conducting cooling at a speed of 20DEG C per minute to 200DEG C, and taking out the product, thus obtaining the europium doped bismuth ferrite film. The preparation method provided by the invention has the advantages of easily controllable reaction process and easily available raw materials. The europium doped bismuth ferrite film has significantly improved crystallization properties and electric leakage properties, and a smaller optical band gap, thus improving the photovoltaic properties of BiFeO3 films. The europium doped bismuth ferrite film has wide application prospects.
Owner:EAST CHINA NORMAL UNIV
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