148 results about "Ultra narrow band" patented technology

The invention disclosed here teaches methods to fabricate and utilize a non-dispersive holographic wavelength blocker. The invention enables the observation of the Raman signal near the excitation wavelength (˜9 cm⁻¹) with the compactness of standard thin film/holographic notch filter. The novelty is contacting several individual volume holographic blocking notch filter (VHBF) to form one high optical density blocking filter without creating spurious multiple diffractions that degrade the filter performance. Such ultra-narrow-band VHBF can be used in existing compact Raman instruments and thus will help bring high-end research to a greater number of users at a lower cost.

The invention provides a method for making deep cut-off ultra-narrow band pass filter. By adopting the method, the effective area and the cut-off of the bandpass filter can be obviously improved and error negative effects can be effectively controlled. The method comprises the following steps of: 1, determining a theoretical film, selecting Ta2O5 as a high-reflectivity material and SiO2 as a low-reflectivity material on the basis of a typical film structure of a multi-cavity optical filter, respectively defining H and L to be the unit optical thickness of the Ta2O5 and the SiO2 on lambda fourth by taking lambda as an operating wavelength of the optical filter, and determining the film structure of the optical filter by using film design software thin film circuit (TFC) Calc on a computer according to performance parameters required by the ultra-narrow band pass filter; 2, making a template control file for automatic control of a coating machine by using the full-automatic coating machine according to the obtained theoretical film structure; and 3, loading selected coating materials in the coating machine and automatically completing the making of the optical filter through a control mode of eccentric monitoring by the coating machine according to a selected template.

The invention discloses a dual-wavelength superheterodyne-interference wide-range high-precision real-time displacement measuring system and method. The system is composed of two lasers between which the wavelength difference is deltalambda, three polarization splitting prisms, four splitting prisms, two acousto-optic modulators, four 1/4 waveplates, five planar mirrors, three Polaroids, a super-narrowband filter plate, two large-bandwidth transimpedance photoelectric detectors, two low-bandwidth high-sensitivity photoelectric detectors, a reference reflector, a measured reflector, a signal processing circuit and a host computer. According to the invention, a synthesized wavelength interference signal generated by dual wavelengths is used to improve the measuring range of the system, so that the measuring range of the system is greater than the range of single-wavelength interference; a superheterodyne interference method is used to demodulate and filter output signals, the phase of the synthesis wavelength can be measured directly, and real-time measurement is realized; and the super-narrowband filter plate is used to collect single-wavelength interference signals, and the precision of single-wavelength interference measurement is ensured while the measuring range is widened.

An ultra-narrow band fluorine laser apparatus is provided in which a line width of a fluorine laser can be narrowed to about 0.2 to 0.3 pm without using any band-narrowing element such as an etalon. In an oscillator 11, a laser chamber 15 is provided in a stable type resonator constituted by an output mirror 13 and a totally reflecting mirror 14. The laser chamber 15 is filled with a laser gas at about 0.8 atm. As a result, when discharge is caused in the laser chamber 15 to cause laser oscillation, laser light L10 in a bandwidth of about 0.3 pm is provided. The power of the laser light L10 is increased by an amplifier 12. The amplifier 12 emits laser light L20 in a bandwidth of about 0.3 pm having laser energy of 10 mJ or more.

Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. Chemical analysis instruments employed in some embodiments include capillary and gel plane electrophoresis, capillary electrochromatography, high performance liquid chromatography, flow cytometry, flow cells for liquids and aerosols, and surface detection instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted simultaneously with native fluorescence spectroscopy to provide high levels of sensitivity and specificity in the same instrument.

Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. Chemical analysis instruments employed in some embodiments include capillary and gel plane electrophoresis, capillary electrochromatography, high performance liquid chromatography, flow cytometry, flow cells for liquids and aerosols, and surface detection instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted along with photoluminescence spectroscopy (i.e. fluorescence and/or phosphorescence spectroscopy) to provide high levels of sensitivity and specificity in the same instrument.

The invention belongs to the technical field of optical space communication, particularly relates to an ultra narrow band excited state faraday anomalous dispersion atom filter of a communication band, and aims at effectively improving the pumping efficiency of the excited state atom filter and overcoming the problems of complicated light path, high demands on an environmental condition, poor adaptability and low practicability caused by a pump laser frequency stabilization module. An external frequency stabilization module is removed by the filter while an Rb atomic vapor absorption peak inside the filter is utilized as a frequency standard. Thus, the ultra narrow band excited state faraday anomalous dispersion atom filter is simpler in structure, better in work stability and higher in efficiency. The scheme is combined with a generation principle of a multi-transition absorption band, and the targeted frequency stabilization mod is adopted, so that a good pumping effect can be obtained.

The invention discloses a vacant frequency spectrum Internet of things communication system and a communication method thereof. The system comprises a vacant frequency spectrum database, a vacant frequency spectrum frequency-band selection module, an upper and lower channel sub-carrier self-adaption module and a UNB communication module. The vacant frequency spectrum Internet of things communication system and the communication method thereof have the advantages that the technologies of scanning detection, frequency hopping and Ultra Narrow Band (UNB) are utilized, the cleaner frequency band of a television vacant frequency spectrum is utilized, the signal cover range with several kilometers or above is provided, the Internet of things communication requirement of several kilometers or above can be met, therefore, the cost of terminal hardware equipment and a network is reduced, the power consumption of a communication terminal is low, and the power supply environment of a button battery for an environment without a power supply is met.

This invention claims a novel radio frequency receiver system for selecting a digitally modulated carrier frequency, and more specifically a Zero Point, amplitude Modulated (ZPM) carrier frequency. ZPM modulation does not create side-band frequencies, thus allowing individual carriers to be very closely spaced. Traditional methods of frequency selection utilize resonant tuning circuits in the antenna circuit and following amplifier circuits. Resonant tuning circuits are the assemblage of inductors and capacitors that are subject to parasitic oscillations, harmonic oscillations, as well as environmental effects. While modern technology has sufficiently overcome these detriments for traditional radio communication, ZPM theory desires to tune to a single frequency carrier with only one cycle of difference between carriers. Obvious to those skilled in the art, this requires a non-traditional method. For ZPM carriers, all signal-handling circuits must be non or insignificantly reactive and process the signal in linear fashion throughout the receiver signal path. This invention accomplishes the required functions by a unique combination of standard integrated circuits and circuit components.

The invention relates to a novel ultra-narrow-band wave absorber of a metal nano ring column array structure. The technical problem of poor quality factor is solved. According to the technical scheme,an ultra-narrow-band absorbing body based on surface lattice resonance is composed of nano ring column arrays, a nano array unit is sequentially provided with a medium layer substrate, a metal film reflecting layer and a resonator from bottom to top, and the thickness of reflecting layer film gold of the nano array unit is greater than the skin depth of an incident electromagnetic wave in precious metal gold. The nano array unit adopts a double-ring-column structure, the full width at half-maximum of the absorption spectrum of the wave absorbing body is compressed, the problems that a traditional wave absorbing body is low in absorbing efficiency, large in full width at half-maximum absorbing, low in quality factor and the like are solved, and the novel ultra-narrow-band wave absorber canbe applied to a narrow-band heat radiator and a plasma biosensor.

An ultra-narrow-band TE (transverse electric) polarizing spectrum selective absorber based on a cascaded fiber grating structure comprises a metal grating layer and a Bragg grating layer from top to bottom, wherein a metal film reflecting layer is further arranged under the Bragg grating layer; the period of the metal grating layer at the top is 365-375nm, the duty ratio of the metal grating layer at the top is 0.48-0.52, the thickness of the metal grating layer at the top is 45-55 nm, the Bragg grating layer in the middle is formed by less than five pairs of dielectric slabs with high refractive index and dielectric slabs with low refractive index, the dielectric slabs with the high refractive index and the dielectric slabs with the low refractive index are arranged in a staggered manner, the thickness of each dielectric slab with the high refractive index is 270-290 nm, the thickness of each dielectric slab with the low refractive index is 300-320 nm, and the thickness of the metal film reflecting film at the bottom is larger than the skin depth of light in the infrared band. The ultra-narrow-band TE polarizing spectrum selective absorber based on the cascaded fiber grating structure can be processed by an electron-beam direct writing device with a microelectronics technology, the materials are convenient to obtain, the manufacturing cost is low, mass production can be realized, and the absorber has broad practical prospect.

The invention discloses a color nano printing device based on a micro-nano polarizer and an F-P cavity structure. A laminated super-surface comprises a substrate, a metal nano-brick array and an F-P cavity array. Based on a metal surface plasmon resonance effect, a polarization-separated metal nano-brick structure can be designed through the specific metal nano-brick size; and a micro-nano F-P array structure with a narrow-band filtering effect can be designed based on a wavelength selection mechanism of the F-P cavity. The metal nano-brick array can be used as a polarizer of blue light, greenlight and red light wave bands under different working states, has a broadband spectral response and intensity modulation function, the micro-nano F-P cavity array with a wavelength selection effectis superposed, and an ultra-narrow band micro-nano polarizer can be constructed and used for realizing a color nano printing function. The color nano printing device provided by the invention can realize wide color gamut, continuous gray-scale modulation and high-resolution color image printing/display, can be widely used in the fields of information encryption, optical anti-counterfeiting, copy painting and the like, and has the prominent advantages of being flexible in design, simple in processing, compact in structure and the like.

The invention provides a modulation method of one-half continuous phase chip keying. The method comprises the following steps: calculating a modulation parameter D according to a modulated signal band width B and a data code element cycle D; generating two phasic frequency variation functions f1(t) and f2(t) corresponding with two modulated signal waveform samples s1(t) and s2(t) according to thecentral frequency fc, the code element cycle T and the modulation parameter D of the modulated signal; generating waveforms samples s1(t) and s2(t) of the modulated signal according to the frequency variation functions f1(t) and f2(t); and generating a modulated signal siT (t) of a first signal code element according to the mapping criterion between the data modulated by binary digit and the modulated waveform samples, and storing the phase at the end of each bit as an initial phase of the next modulated waveform. The invention provides a digit modulation communication method with continuous phases and continuous frequency variation of the modulated signal among code elements, the method is a band-pass ultra narrow-band communication method, the energy of the modulated signal in the method is mainly centralized close carrier waves, the frequency-band utilization ratio is high, and high-speed data transmission in an ultra-thin band width can be realized.

The invention relates to an underwater acoustic communication method based on very minimum chirp keying modulation. The method comprises that: a transmitter drives an underwater acoustic transducer by using a very minimum chirp keying modulated ultra-narrowband signal as a transmission signal source to generate chirped longitudinal waves for transmission in water; and a receiver converts an acoustic signal into an electric signal for demodulation by the transducer. By the method, a frequency band utilization rate is extremely high. The communication method is applied to underwater acoustic communication and aims to explore a new technical path for the underwater acoustic communication, realize high-speed underwater acoustic information transmission and increase the frequency band utilization rate in a signal transmission process. The method is expected to be applied to future submarine military communication.

The invention belongs to the technical field of space optical communication and particularly relates to an excited state Faraday anomalous dispersion atomic filtering method for an ultra narrow band of a communication waveband. In order to effectively increase the pumping efficiency of an excited state atomic optical filter and overcome the defects of complex optical path, high environment condition requirement, poor adaptability and low practicability caused by a pumped laser frequency stabilizing module, the operation step for externally placing a frequency stabilizing module is omitted while Rb atomic vapor absorption waves inside an optical filter are used as frequency standards, so that the method is relatively simple in operation process, relatively good in working stability and relatively high in efficiency; moreover, the scheme is combined with a multi-transition absorption band generating principle, and a frequency stabilizing way with rather strong pertinence is adopted, so that a good pumping effect can be obtained.

The invention provides a heterodyne detection device based on light injection locking and a light phase-locked loop, which comprises a polarization tracking section, a heterodyne detection section anda down-conversion section, and is characterized in that the heterodyne detection section comprises an injection locking section, a coherent detection section and a light phase-locked feedback loop; the injection locking section comprises a first polarization-maintaining optical branching device, an optical phase shifter, a polarization-maintaining circulator, a local laser and a second polarization-maintaining optical branching device; the coherent detection section comprises a polarization-maintaining 2 * 2 3dB coupler, a balance light detector pair, a low-noise trans-impedance amplifier anda first power divider; the optical phase-locked feedback loop comprises a first amplifier and a loop filter; the down-conversion section comprises an ultra-narrow band-pass filter, a second amplifier, a second power divider, a phase shifter, a pi/2 power divider, a third amplifier, a third power divider, a first mixer, a second mixer, a first low-pass filter and a second low-pass filter. Heterodyne detection is adopted, frequency synchronization of LO light waves and main control light waves is achieved, the receiver achieves zero frequency deviation, phase noise is small, and output signalsare stable.

Belonging to the field of electric power technology, the invention specifically relates to a wireless transmission anti-missort tester and a working method thereof. The wireless transmission anti-missort tester includes a transmission device and a receiver, the transmission device is equipped with a power supply module, an ultra narrow band frequency selection module, a transmission channel and aground wire terminal. The ultra narrow band frequency selection module and the transmission channel are in parallel connection, the ground wire terminal is connected to the ultra narrow band frequencyselection module, and the output end of the ultra narrow band frequency selection module is connected to the input end of an amplification circuit. The tester provided by the invention can carry outdetection positioning without enter a household, and omits tedious access procedure. The tester has the advantages that: the time for correction detection of a user meter is short, the work efficiencyis improved, unified inspection is carried out on a plurality of electric meters in one meter box, and the operation is simple and convenient.

The invention relates to a time-sharing system time slot setting method for determining time slot numbers based on time marks and time slot positions. The method comprises the steps that within the range of a base station, a reporting period is composed of a plurality of time slots, and the starting position of each time slot is unique in each time mark period defined by a system within the reporting period; terminals acquire own reporting time slot numbers in the access process, then are dormant, and are awakened before the reporting time slots of the terminals is up, the time slot numbers of current work are obtained by monitoring the starting positions of the previous time slots, and the reporting time of the terminals is corrected. The method is combined with the ultra-narrow band wireless transmission technology, a framework Internet of Things sensor network can be solved well, the method is used for constructing a large-area Internet of Things sensor network, and application products comprise the terminals and the base stations. The method has the advantages of being high in transmission efficiency, small in power consumption, low in cost and large in system capacity.