1075 results about "Dual wavelength" patented technology

A combination of a patient core temperature sensor and the dual-wavelength optical sensors in an ear probe or a body surface probe improves performance and allows for accurate computation of various vital signs from the photo-plethysmographic signal, such as arterial blood oxygenation (pulse oximetry), blood pressure, and others. A core body temperature is measured by two sensors, where the first contact sensor positioned on a resilient ear plug and the second sensor is on the external portion of the probe. The ear plug changes it's geometry after being inserted into an ear canal and compress both the first temperature sensor and the optical assembly against ear canal walls. The second temperature sensor provides a reference signal to a heater that is warmed up close to the body core temperature. The heater is connected to a common heat equalizer for the temperature sensor and the pulse oximeter. Temperature of the heat equalizer enhances the tissue perfusion to improve the optical sensors response. A pilot light is conducted to the ear canal via a contact illuminator, while a light transparent ear plug conducts the reflected lights back to the light detector.

A method of measuring Photoplethysmography (PPG) signals may comprise detecting dual wavelength illumination from a light detector so as to provide detected signals, converting the detected signals into digital signals so as to provide digital signals, reducing noises from the digital signals and increasing independency between the digital signals so as to provide preprocessed signals, subtracting the average value from the preprocessed signals so as to provide adjusted signals, obtaining whitening matrix based on covariance, eigen value, and eigen matrix obtained from the adjusted signals, and restoring data using the whitening matrix.

A single-frequency Brillouin fiber ring laser with extremely narrow linewidth comprises a single-frequency narrow-linewidth rapid-tunable pump laser, a temperature-controlled acoustically-damped package for Brillouin fiber ring laser cavity, and an auto-tracking feedback electronic loop with novel configuration for active stabilization. The Pound-Drever-Hall frequency-locking technique is employed to keep pump laser frequency in resonance with one of the Brillouin fiber ring cavity modes. Instead of changing cavity length of Brillouin fiber ring laser, the pump laser frequency is rapidly tuned in the auto-tracking feedback electronic loop. This enables extremely narrow linewidth radiation emitted from a Brillouin fiber ring laser without stretching the fiber ring. Dual-wavelength actively stabilized Brillouin fiber ring laser may be generated from a single ring cavity by polarization-combining or wavelength-combining two pump laser beams and using two independent feedback loops to the two operation wavelengths.

The invention relates to a sensing method with an optical-fiber Bragg grating laser device. An optical-fiber Bragg grating is used as a reflector of the resonant cavity, an active optical fiber capable of generating sufficient gains is added, and a double wavelength/multiple wavelength optical-fiber Bragg grating laser device is formed under the action of a pump light source and used as a sensor. When the outside strain, temperature and other physical quantities act on the sensing system, the beat signal frequency among the double wavelength or multiple wavelength laser can shift, and counter stress, temperature and other physical parameters can be measured precisely by detecting the beat signal frequency information. The invention has the advantages of simple manufacture, stable and reliable operation, stable measurement result and high precision, and is free from the interference of light intensity, polarization and other optical information quantities. The multipoint distribution sensing measurement can be realized in a frequency-division multiplexing mode. An electrooptical modulator is added before the spectrum analyzer starts detection so as to randomly adjust the beat signal frequency, thereby greatly reducing the spectral range of the spectrum analyzer and reducing the detection cost.

The invention relates to an aerosol grain size sensing method based on dual-wavelength scattered signals and an application of the method to fire smoke detection, and belongs to the technical field of fire alarms. The method comprises steps as follows: calculating the ratio R of the blue light scattered power to the infrared light scattered power after receiving corresponding scattered signals reflected by aerosol with the blue light scattered power PBL and the infrared light scattered power PIR; determining the median grain size dmed according to the relation between the ratio R of the blue light scattered power to the infrared light scattered power and the median grain size dmed of aerosol; comparing the blue light scattered power PBL and the infrared light scattered power PIR with set corresponding thresholds PBLth and PIRth, and sending corresponding interference prompt signals or corresponding firm alarm signals. With the adoption of the method, fire type alarm signals can be judged and sent, so that targeted reasonable measures can be taken, and meanwhile, false alarms caused by aerosol under non-fire conditions can be avoided.

The invention discloses a dual-wavelength binocular vision seam tracking method. The method comprises the steps including image acquisition, data processing, seam tracking and the like. The invention further discloses a tracking system for implementing the method. The system adopts a near-infrared and structured light dual-wavelength binocular vision sensing system, images of a molten pool and different wavelengths of seam area images with of seams are measured simultaneously and transmitted to a miniature industrial control computer, and the seam positions are measured accurately with a multi-information fusion algorithm and a seam image three-dimensional reconstruction algorithm; the miniature industrial control computer adopts the Kalman filter algorithm to perform optimal estimation on the seam tracking deviation state according to a seam position detection result, a servo driver drives a servo motor to move so as to control a 3-axis motion workbench to generate corresponding motion, a welding torch or a laser head is controlled for deviation correction, and the seams are tracked accurately. The system can eliminate hard light, splashing and electromagnetic interference on a welding site and improve the seam tracking accuracy and reliability.

The invention relates to a metal powder laser rapid prototyping technology, in particular to a temperature field detecting method and the system device in the working process of the rapid prototyping of the metal powder. The invention adopts dual wavelength infrared image colorimetric temperature measuring method, the optical filters in two wavelengths are alternately arranged in the gathering optical path at different times, the image in the fused bath from two different wavelength are continuously and orderly gathered, and the color matching calculation of the gradation of the two infrared image from different wavelength are performed, according to the relationship between the color matching value and the temperature value, the temperature value of each point of the image is acquired, the temperature value is represented by the tonal value and a gradation image is formed, the gradation image then is processed, and the shape and temperature changing trend is acquired. By adopting the invention, the temperature distribution and the changing trend of the temperature field of the fused bath can be detected in real time during the rapid prototyping process of the metal powder, and then the temperature of the work piece process parameter can be adjusted in real time.

The invention discloses a biological tissue blood flow, blood oxygen and blood volume multi-parameter detection method and device. According to the method, two laser beams, differing in wavelength, simultaneously irradiate a biological tissue; and multiple frames of biological tissue colored images, which are illuminated by the laser beams, are continuously acquired by a photoelectric imaging system. The light intensity values of a red channel and a green channel on each pixel of the images are obtained for respectively constituting a red channel image and a green channel image. By virtue of a laser speckle blood flow imaging data analysis method and a dual-wavelength spectroscopic data analysis method, the red channel image and the green channel image are processed, so that two-dimensional spatial distribution and dynamic variation information thereof of a plurality of physiological parameters including blood flow, oxyhemoglobin concentration and reduced hemoglobin concentration of the corresponding biological tissue are obtained. The method and the device disclosed by the invention solve the shortcoming that a multi-wavelength time-sharing imaging based multi-parameter blood flow imaging system has difficulty in achieving the synchronization of accurate time and also avoid the shortcoming that a multi-camera shooting based multi-parameter blood flow imaging system is high in cost due to the use of a plurality of cameras.

Multiple wavelength spectrometers can be tuned to particular wavelengths. A dual wavelength spectrometer can include a spectrometer configured to detect at least some wavelengths that fall within the ultraviolet (UV) spectrum and a spectrometer configured to detect at least some wavelengths that fall within the visible spectrum. In some embodiments, a UV light spectrometer and a visible light spectrometer are disposed adjacent one another on a single substrate. A dual wavelength spectrometer can be used for analyzing bioaerosols, as well as for numerous other applications.

The invention discloses a single-light-source dual-wavelength LIBS (laser-induced breakdown spectroscopy) measurement device and method. The device mainly comprises a pulsed laser device, a frequency multiplying crystal, a light splitter, a first total reflector, a second total reflector, a light shutter, a spectrograph and a synchronous delay controller, wherein laser generated by the pulsed laser device passes through the frequency multiplying crystal, and then is divided into fundamental frequency light and frequency multiplying light, and is irradiated to the light splitter; the frequency multiplying light is reflected by the first total reflector, and is vertically irradiated to the surface of a to-be-detected sample; the fundamental frequency light passes through the light shutter, then is reflected by the second total reflector, and then is irradiated above the surface of the to-be-detected sample by 1-5mm in parallel; spectrum signals generated by a plasma stimulated from the to-be-detected sample are converged to an optical fiber collecting head, and are transmitted to the spectrograph. The single-light-source dual-wavelength LIBS measurement device provided by the invention has the advantages of simple structure, compact volume and low price while achieving dual-pulse LIBS high detection sensitivity, and can be widely applied to the technical field of laser diagnosis and spectrum analysis.

The invention relates to a femtosecond laser-controlled silicon surface nanopillar preparation method based on dual-wavelength electronic dynamic control, and belongs to the technical field of femtosecond laser application. The method comprises the steps that on the basis of local instant electronic exciting dynamic control, the wave length of the fundamental frequency laser is converted into 400 nm from 800 nm through a frequency doubling technology, and the surface micro-nano structural morphology is controlled by adopting a dual-wavelength femtosecond laser, wherein a first beam generates a generic plasma lens structure (PL) on the surface of a material, a second beam generates surface plasma along the edge of the generic PL structure and generates a gradient field distributed along the center of a light spot, and then the material generates the force extruding towards the center under the action of the pulse to form a convex nanopillar structure; preparation of large-area uniform nanopillar arrays is achieved through control over a procedure of a processing platform. Compared with an existing method, the preparation method has the advantages that the nanopillar processing precision and processing efficiency are effectively improved, efficient and precise control over the crystalline silicon surface nano structure is achieved, and the application value on the aspects such as information storage and solar cells is achieved.

The invention provides a bench-type laser precision washing device with dual-wavelength composite energy distribution, comprising a workbench, an X-Y electric module, a turntable component, a laser washing component, and a Z-directional lifting bench; the X-Y electric module is fixedly mounted on the workbench, the turntable component is mounted on the X-Y electric module, the Z-directional lifting bench is mounted on the workbench, and the laser washing component is mounted on a lifting plate of the Z-directional lifting bench; the laser washing component includes a laser, a transmission fiber, a blow nozzle, a laser ranging sensor, a galvanometer scanning system and a dual-wavelength composite reshaping system; a laser beam emitted by the laser is transmitted by the transmission fiber and enters the dual-wavelength composite reshaping system; the dual-wavelength composite reshaping system outputs a dual-wavelength composite reshaped beam that passes through the galvanometer scanning system and is focused on the surface of material. The bench-type laser precision washing device has the advantages that washing uniformity and fineness are improved, damage to material matrix is effectively decreased via circular spacing, and washing quality is greatly improved.

The invention provides a method for preparing a two-dimensional periodic metal particle array structure through dual-wavelength femtosecond lasers. The method and an implementation device for preparing the two-dimensional periodic particle array structure on the surface of metal by focusing two-color femtosecond laser pulses are provided. The method and the implementation device are characterized in that the metal particle structure is distributed in the two-dimensional direction in a periodic submicron dimension mode; two-color femtosecond lasers with different characteristic parameters are collinearly focused and irradiated on a sample after common channel or branch channel time delay through a nonlinear frequency doubling technology, and formed two-dimensional periodic structure patterns can be effectively adjusted and controlled by changing the azimuth angle of frequency doubling crystals and the power ratio of the two-color lasers. The method has the advantages that through the combinational design of different wavelengths and the polarization property of the femtosecond lasers, the submicron dimension two-dimensional periodic metal particle array structure can be conveniently and quickly prepared. The novel method for preparing the structure through the two-color femtosecond lasers has potential and important application value in the field of material micro-nano processing.

This invention discloses dual field view dual-wavelength laser radar scattering meters structure and detection methods, including laser launch unit echo signal receiver modules, the follow-up optical modules, signal detection and acquisition module and control unit; The laser launch unit using Nd: YAG laser, launching 532 nm and 1064 nm wavelength of the laser pulse at the same time and received by the diameters of 400 mm and 200 mm telescope. Two receiving optical telescope module are follow-up optical module. Optical signal from the follow-up optical module are received by the detection and acquisition module and control unit. atmospheric aerosol extinction coefficient of the vertical profile and continuous distribution, and extinction coefficient level of continuous distribution, can be analyzed through the various atmospheric aerosol optical parameters.

A hybrid catheter device for performing cutting action on a region of a tissue, using sequential laser and mechanical cutting processes, and incorporating an acoustic sensor on the end of the device, such that if a pulsed laser beam is used for the laser cutting, the absorption of that beam in the tissue being cut can provide information about the progress of the cut by means of the opto-acoustic effect. Other hybrid catheter devices incorporate blunt protrusions on the end of said device, but having sharp lateral edges, such that rotation of the catheter device generates mechanical cutting action in the tissue. The blunt protrusion ends prevents uncontrolled cutting in the forward motion. Other hybrid catheter devices enable controlled incisions into an organ wall, such as the duodenum, and held in place by means of an inflatable balloon. A dual-wavelength nail fungus treatment hybrid catheter is also shown.

The invention discloses a real-time multi-mode photoacoustic human eye imaging system and an imaging method thereof. The imaging system comprises a laser device, a front optical path, a reflecting mirror, a focusing lens, a light-transmitting acoustic reflection device, a scanning mirror, a water trough, an ultrasonic probe, an ultrasonic transmitter-receiver set, an amplifier and a computer. A light-transmitting acoustic reflection film and the scanning mirror are placed in the water trough. The imaging system has a photoacoustic imaging mode and an ultrasonic imaging mode. Mechanical scanning is replaced through the scanning mirror, imaging time is greatly shortened, and pain of a patient is relieved. Meanwhile, due to the optical and ultrasonic confocal design, an existing pure optical focusing imaging mode or an existing pure ultrasonic focusing imaging mode is changed, sensitivity is improved on the basis that the optical resolution is achieved, and full-eye imaging from the front of the eye to the bottom of the eye can be carried out. Due to dual-wavelength use, the limitation that imaging is only carried out on the eye vascular structure at present is broken through, functional imaging of the degree of blood oxygen saturation can be carried out, and early detection of a part of eye diseases is facilitated.

The invention provides a dual wavelength common-channel quadrature carrier frequency digital holographic detection apparatus and a detection method. A non-polarization splitting prism splits converged dual wavelength incident light into reflected reference light and transmitted object light; the reference light irradiates an aperture reflector and is reflected; the object light is split into dual wavelength object lights when passing through a dichroscope; the dual wavelength object lights separately irradiate a first reflector and a second reflector and are reflected and passes through the dichroscope to merge into a beam of object light; The reflected reference light and object light are combined by a non-polarization splitting prism into a beam of light which passes through a second lens to form a quadrature carrier frequency hologram which is collected by a computer via an image sensor and the phase of the object to be measured is calculated. The detection method ensures the anti-interference ability and wrap-free real-time detection; and the method is simple and is easily implemented without need of any optical members such as polarization elements and space filter arrays, and only the hologram recorded by a black-white image sensor and completion of the dual-wavelength hologram separation by a simple algorithm are needed.

The invention discloses an all-optical wavelength converting device based on non-linear optical waveguide. The device comprises a first optical coupler, an erbium-doped optical fiber amplifier, a polarization controller, a PPLN waveguide, an optical isolator, a second optical coupler and a pump optical wavelength selector, which are connected in sequence by optical paths in clockwise direction to form an annular cavity laser with the built-in PPLN optical waveguide. The first optical coupler and the second optical coupler respectively provide a signal light input port and a converted idle light output port for the external. The non-linear optical waveguide is the PPLN optical waveguide and the pump optical wavelength selector is a dual wavelength selector or a multiple wavelength selector. The pump light produced by signal light and the inner of the annular cavity by lasing carries out non-linear mutual interaction in the PPLN optical waveguide to generate converted idle light, so as to realize wavelength converting. The device can realize tunable wavelength converting of single-channel to dual-channel and single-channel to multi-channel (broadcasting type) and input and output tunable wavelength converting with the advantages of flexible converting function, compact and easily realizable structure and low cost.