327 results about "Laser polarization" patented technology

The present invention includes novel techniques, apparatus, and systems for optical WDM communications. Various wavelocker apparatus and methods are disclosed that measure the frequency offsets between signal lasers and reference lasers. The measured offsets are used to adjust the signal laser frequencies to meet their target frequencies. The absolute accuracy of the reference laser frequency is improved by measuring the absorption of the reference laser by a gas cell with known fixed absorption lines versus the reference laser frequency. Apparatus and methods are disclosed to cover scenarios in which the reference laser polarization is aligned with the signal lasers, as well as those in which the reference laser polarization is not aligned with the signal lasers. The wavelocker apparatus may or may not be located at the same network site as the signal lasers.

The invention belongs to the technical field of optical precision measurement, relating to super-resolution laser polarization differential confocal imaging method and device. The method improves the transverse resolution power by combining a radial polarized light and a pupil filtering technology, improves the axial resolution power by using a differential subtraction detection technology of an axial-offset dual-detector system and remarkably improves the spatial resolution power and tomography ability of the system. The device comprises a laser source as well as a beam expander, a polarization state modulation system, a pupil filter and a spectroscope which are sequentially arranged at a transmitting end of the laser source, an objective and a sample which are arranged in the transmitted light direction of the spectroscope in turn, and a differential confocal system in the opposite direction of the reflected light direction of the spectroscope. The invention combines the radial polarized light resolution technology with the pupil filtering technology and improves the transverse resolution power of the system; moreover, the differential work mode of the invention can remarkably improve the axial imaging ability of the system and is applicable to the high-precision detection and metering of nanometer-level geometrical parameters in the nanometer manufacturing field.

The invention discloses a difference method for improving the sensitivity and the absolute precision of a CPT (Coherent Population Trapping) atom magnetometer. The method comprises the following steps: putting a low-intensity magnetic field probe in a magnetic field to be detected at a constant temperature; adjusting a laser control circuit to keep the laser wavelength stable and keep resonance of the laser wavelength and alkali metal atomic ground state level; vertically putting a half-wave plate and a polarization beam splitter prism in laser, and adjusting the polarization angle of the optical axis of the half-wave plate and the laser; enabling a quarter-wave plate to be vertical to two beams of parallel laser; adjusting the polarization angle of the optical axis of the quarter-wave plate and the laser, wherein the polarization of the parallel laser becomes left-hand circular polarization and right-hand circular polarization respectively; carrying out laser detection on the left-hand circular polarization and the right-hand circular polarization by two photovoltaic conversion devices, and subtracting obtained light intensity values by a subtracter, wherein the magnetic induction intensity B of the magnetic field to be detected is obtained through acquisition and signal processing of data acquisition and processing equipment. The difference method has the advantages of easy operation, high sensitivity and high precision.

The invention discloses a loss testing apparatus for a multi-channel optical device, which comprises an optical source module used for supplying laser of various wavelengths and stable power, an optical amplifying module used for amplifying an optical source for a return loss test and equally dividing the optical source into a plurality of channels, an optical power detecting module used for measuring the optical power and the return loss of an output end of the optical device to be measured, a polarization controller used for changing the polarization state of an input optical source, an optical source monitoring module used for detecting the stability of the optical source and testing the return loss of a public end of the device, an optical switch used for selecting one output in the laser of various wavelengths, a single chip computer and a communication module used for controlling a switching channel of the optical switch, wherein the polarization controller is used for changing the polarization state of the laser, receiving the data measured by the optical power detecting module and the optical source monitoring module and processing the data. By adopting the loss testing apparatus provided by the invention, the testing efficiency of various indexes for the multi-channel optical device can be increased to large extent.

An illuminator that illuminates a projected surface includes a laser light source that emits laser light; a polarization converter disposed downstream of the laser light source, the polarization converter having a first area that converts the polarization direction of incident laser light into a first polarization direction and outputs the resultant laser light and a second area that converts the polarization direction of incident laser light into a second polarization direction and outputs the resultant laser light; and a light diffusion section disposed downstream of the laser light source, the light diffusion section diffusing incident laser light.

The invention discloses a coherent wind measurement laser radar system with adjustable range resolution. In one aspect, the system employs a polarization circular beam splitter 3, locks vertical polarized light in a circular device, and repeatedly passes through AOM to allow emitted laser to generate n upsilon M frequency shift, thereby adjusting laser frequency shift; in another aspect, the system employs EOM 5 to cooperate with the polarization circular beam splitter 3, converts the polarization state of the laser in the circular device reaching preset offset into parallel vibration from vertical polarization, and converts continuous wave laser into pulse width adjustable pulsed light, thereby realizing the adjustment of the range resolution of a coherent wind measurement laser radar. The scheme not only improves the applicability of the coherent wind measurement laser radar on different resolution requirement occasions and under different weather, but also improves the data measurement reliability of the coherent wind measurement laser radar.

The invention relates to a collinear femto-second laser polarized pump detecting system, comprising that a pulse laser is output by a polarized output pulse laser; the laser is rotated in the polarization direction by a wave plate; a light-splitting device divides the laser beam into two beams vertical to each other in the polarization direction; a reflector receives and reflects the laser beams; an acoustooptic modulator modulates the laser beams; an aperture transmits the modulated laser beams; an acoustooptic modulator driver transmits modulation signals for the acoustooptic modulator; an electrically controlled travelling carriage moves forward and backward; an analyzer transmits the laser beams which are vertical to each other in the polarization direction; a photodetector receives the laser transmitted by the analyzer; a magnet fixes an adjusting rack so as to fix a sample; a focusing lens irradiates the laser on the surface of the sample; and an electrically controlled revolving stage fixes the wave plate. The invention combines the two beams of light vertical to each other in the polarization direction by polarized coupling; therefore, the system can ensure spatial coherence of the two beams of light on the sample, thereby avoiding the problem of adjusting direction of light beam; thus, the operation is simpler.

The present invention belongs to the field of laser measurement technology, and features that 632.8 nm He-Ne laser and outer high reflectivity reflector constitute one non-collimated multiple laser feedback system. The outer reflector is fixed onto the tested object, and when the tested object is shifted, the laser strength fluctuation frequency may reach several to decades times that of the traditional feedback mode to result in high order frequency multiplying effect in laser strength fluctuation. The laser strength fluctuation period corresponds to nanometer level change in the distance between the outer reflector and the laser, so that measuring the period number of the laser strength variation can obtain the displacement of the measured object. When the object changes its moving direction, the laser polarization state jumps between two orthogonal directions and this may be used in judging the moving direction of the object.

The invention relates to an application of femto-second laser in the surface treatment of the pure titanium implanting material, belonging to the technical field of application of laser in the material surface treatment. The application method comprises the following steps: in the air, the femto-laser impulse is in normal incidence and focused right on the top of the lump pure titanium implanting material which is ground and dried, a light spot with a radius of 5um is formed at the surface of the pure titanium implanting material, the femto-laser processing parameters are defined as follows: the impulse repeat frequency is 1 kHz, the single impulse power is from 5 to 200 micro joule, the impulse width is 50 femtosecond, the impulse center wavelength is 800 nanometer, the line interval of the laser processing is between 10 to 100 micron, the laser scanning speed is between 0.5 to 1.2 mm/sec, the laser polarization direction is regulated to be parallel to the laser scanning direction, the femto-laser scans the whole surface of the pure titanium implanting material, a titanium based biomedical material with an oxide layer generated on the titanium surface, even roughness, and a pattern of strips, holes, grooves or the combined pattern thereof formed on the pure titanium implanting material is made.

The invention discloses a method and a device for strengthening atom steam optical filtering signals by combined Raman. The method combines two characteristics of atom excited Raman gain and Faraday anomalous dispersion effect of atom steam in a single atom steam bubble. The device for realizing the method comprises a narrow band polarization beam splitter, two holophotes, an atom steam bubble with an external magnetic field with a part of size, an aperture slot with adjustable pore size and a pair of Gran Thomson prisms. In the invention, the atom steam optical filtering signals are strengthened by above 10 times in the atom steam bubble with the external magnetic field with a part of size through vertical direction of weak signal light and pump laser polarization and matching frequency, and scattered light and passband external background light of pumping lasers are inhibited by an optical polarization device, therefore, the device has the advantages of high suppression ratio (-105), adjustable optical filtering wavelength and the like. The invention remarkably enhances the atom steam optical filtering characteristic and the detection sensitivity and has important significance to application in the fields of remote laser communication, free space quantum communication and the like.

The invention discloses a loss analysis device of a passive device, comprising a multi-wavelength light source, an optical switch, a polarization controller (PC), a shunt, a return loss test module, an optical power meter module and a singlechip, wherein the multi-wavelength light source is used for providing multi-wavelength lasers with stable power; the optical switch is used for selecting one of the multi-wavelength lasers for output; the PC is used for changing the polarization state of the lasers; the shunt is provided with a first end, a second end and a third end; the return loss test module is used for testing optical power reflected by the input end of the passive device to be tested; the optical power meter module is used for testing the optical power of the output end of the passive device; and the singlechip is used for controlling the laser output of the multi-wavelength light source, the laser selection of the optical switch and the changes of the PC for the laser polarization state, receiving data tested by the return loss test module and the optical power meter module, and processing the data. The loss analysis device is a multifunctional device which integrates the functions of a stable distributed feedback (DFB) light source, the optical power meter module, a plugging-return loss test set, and a polarization dependent loss (DPL) tester into a whole.

The invention discloses a mode selection coupler based 8-shaped cavity mode locking column vector fiber laser including a pump source, a wavelength division multiplexer, a gain fiber, a single-mode fiber, a first polarization controller, a second polarization controller, a 3dB coupler, an isolator, a coupler and a mode selection coupler. The output terminal of the pump source is connected with a short wavelength input terminal of the wavelength division multiplexer. The output terminal of the wavelength division multiplexer is connected with a 1 port input terminal of the 3dB coupler through the gain fiber, the single-mode fiber and the first polarization controller successively. A 2 port input terminal of the 3dB coupler is connected with a long wavelength port of the wavelength division multiplexer. A 4 port is connected with a 3 port of the 3dB coupler through the isolator, the coupler and the mode selection coupler successively. Therefore, an 8-shaped resonance cavity is formed. The second polarization controller is connected with a less-mode fiber output terminal of the mode selection coupler. The invention has advantages of being narrow in fiber laser output pulses, high in column vector laser polarization purity, small in loss and low in cost.

Provided is a polarization resistance single line polarization interference and single Woodward prism spectral homodyne laser vibrometer, belonging to the laser interference measuring field. An interference portion utilizes a half-wave plate, a quarter-wave plate and an NBS to generate +/-45 DEG linear polarization reference light and linear polarization measuring light orthorhombic in a one way polarization direction and having light paths overlapped; the reference light and measuring light of a detection portion are split and generate four paths of optoelectronic signals with a phase position difference of 90 DEG through a same Woodward prism, thereby restraining outstanding features of non-linear errors from an optical path structure and principle. The vibrometer realizes four channel homodyne orthogonal laser interference measurement, effectively solves the problems that, in the prior art, polarization leakage and polarization aliasing exist in the optical path, output signals exist direct current biased errors and nonopiate errors, and non-linear errors of measuring results are obvious, and possesses significant technical advantages in an ultra-precision vibration measuring field.

The invention belongs to the technical field of laser and relates to a laser device, in particular to a laser device capable of freely switching laser between 1064nm wavelength and 355nm wavelength. The laser device comprises a pumping source (1), an energy transfer fiber (2), a coupling system (3), a laser gain dielectric crystal (5), a Q switch (6), an activizer (7), a polarizing spectroscope (8), a frequency doubling crystal (11) and a sum frequency crystal (12). The activizer (7) is used for controlling rotation of a laser polarization plane, so that the laser penetrates through the polarizing spectroscope (8) or are reflected to select different channels of laser oscillation, thus realizing different wavelength output; and under the control of the activizer (7), the laser can be freely switched in the different output wavelengths.

The invention relates to a unimodal 87 Rb isotopic atomic filter used for laser frequency stabilization and a method for filtering by adopting the atomic filter. The filter consists of components of an external cavity laser 1, an optical isolator 2, a first semipermeable semi-reflective mirror 3, a second semipermeable semi-reflective mirror 4, a first high reflectivity mirror 5, a natural rubidium cell 6 and the like. According to the unimodal 87 Rb isotopic atomic filter used for laser frequency stabilization and the filter method thereof, by using the Faraday anomalous dispersion effect of isotopic 87 Rb ground state atoms in a magnetic field, a uniform magnetic field is generated through a magnetic field source, such as a permanent magnet, and the laser and atoms are interacted, so the laser polarization direction is changed. The laser transmission polarization direction is limited by two polarizing prisms, the light wave with specific frequency is chosen, and the goal of filtering is achieved. A system is enabled to be in a good working condition through a temperature control system. The unimodal atomic filter has the advantages of simple structure, high filtering performance, work stability, long service life and the transmission rate of being more than 78.0%. The unimodal 87 Rb isotopic atomic filter used for laser frequency stabilization and the filter method thereof have important significance in the experiment with interaction between light and atoms.

The invention relates to a method for regulating and controlling a crystalline silicon surface corrugated structure based on a plasmoid lens effect and belongs to the technical field of femtosecond laser application. According to the method, a metal nano-ring structure is processed on based silicon plated with a noble metal film in advance by fundamental frequency femtosecond laser pulse after single frequency multiplication is adopted, a second beam of single traditional fundamental frequency gauss femtosecond laser pulse acts on the nano-ring structure, and processing of a base crystalline silicon surface ring-shaped concentric corrugated structure is realized under the action of the plasmoid lens effect of a noble metal nano-structure. When linear polarization femtosecond laser pulse isadopted, the processed corrugated structure is distributed in a semi-ring shape and a corrugated symmetrical shaft is perpendicular to the laser polarization direction; when circular polarization femtosecond laser pulse is adopted, the processed corrugated structure is in a ring distribution shape in a centrosymmetric way. According to the method, efficient and accurate control of the surface periodical micro-nano structure form is realized, and crucial application value in the aspects of surface wettability and image storage is achieved.

The invention relates to a two-tone femtosecond laser collinear pumping detecting thermal reflection system which comprises a polarization output pulse laser, a wave plate, a beam splitting element, a reflecting mirror, an electro-optical modulator, a frequency doubling crystal, an optical filter, a beam expander, an electronic control displacing platform, a cold-light mirror, a fixing adjusting frame, a focusing lens, a photoelectric detector and a filter amplifier, wherein the polarization output pulse laser is used for outputting a pulse laser; the wave plate is used for causing the laser to rotate along a polarization direction; the laser beam is divided into two mutually vertical beams along the polarization direction by the beam splitting element; the laser beam is received and reflected by the reflecting mirror; the laser beam is modulated by the electro-optical modulator; the frequency doubling crystal is used for causing the laser to generate second harmonics; the laser within an appointed wavelength interval is filtered by the optical filter; the diameter of the laser beam is expanded by the beam expander; the electronic control displacing platform can move back and forth; the laser beams with different wavelengths are combined by the cold-light mirror; a sample is fixed by the fixing adjusting frame; the laser is irradiated on the surface of the sample by the focusing lens; the photoelectric detector is used for receiving the laser passing through the optical filter and generating an electric signal; and the signal of the photoelectric detector is amplified by the filter amplifier. According to the two-tone femtosecond laser collinear pumping detecting thermal reflection system, femtosecond pulse lasers with different wavelengths are applied to pumping light and detecting light; the pumping light after being subjected to frequency doubling is filtered by the optical filter with high selective permeability; the interference of the pumping light to a detecting signal is avoided; and the accurate high-efficient measurement is realized.

The invention provides a device for combining a plurality of beams of pulse beacon sub lasers of low average-power and low repetition-frequency to generate pulse sodium beacon lasers of high average-power and high repetition-frequency. The device comprises a pulse sodium beacon laser system, a polarization combination system, an image transmission system and a time sequence combination synchronous control system. The device is characterized in that the pulse sodium beacon laser system can generate a set of time sequence pulse sodium beacon lasers under the control of the time sequence combination synchronous control system; the beams of pulse sodium beacon lasers of low average-power and low repetition-frequency are combined into a beam of pulse sodium beacon lasers of high average-power and high repetition-frequency through a polarization time sequence combination technology, and meanwhile the wave length and the line width of each beam of pulse sodium beacon sub lasers are enabled to be consistent through utilization of a seed injection technology. Compared with the effect before combination, according to the sodium beacon lasers, the polarization degree of single route of laser is not changed, the beam directivity is not changed, the beam quality is not changed, the wavelength is not changed and the line width is not changed, and performance of the sodium beacon lasers is effectively improved.

The invention discloses an active ring resonator-based single longitudinal mode low noise narrow band column vector fiber laser. The single longitudinal mode low noise narrow band column vector fiber laser comprises a pumping source, a wavelength division multiplexer, a gain fiber, an isolator, a coupler, a seed source, a first optical circulator, a second optical circulator, a single-mode fiber, a few-mode fiber engraved with a grating, a first polarization controller and a second polarization controller which are connected with one another in a closed end-to-end manner through a fiber coupling way to form a ring optical fiber resonator. The components of the single longitudinal mode low noise narrow band column vector fiber laser adopts an all-fiber coupling mode; the structure is compact, the polarization purity of output column vector laser is high, the coherence is well, a single longitudinal mode working manner is realized, and the spectrum stability is high.

The invention relates to a method for electronic dynamic control of crystal silicon surface periodic micro-nano structures based on square hole assistance and belongs to the technical field of femtosecond laser application. The method is based on local transient electronic excitation dynamic control, and femtosecond laser linear polarization is focused through an objective lens and then is focused on the surface of a material through a square hole copper wire mesh to achieve various precise control of different surface periodic micro-nano structures; by controlling laser scanning speed and pulse energy, ablation of strip-shaped surface corrugated structures and multi-point array micro-nano structures is achieved; by controlling the relative positions of the laser polarization direction and the direction (x axis) of the edge of a square hole, direction control of the periodic micro-nano structures can be achieved; by effectively adjusting the included angle between the linear polarization laser direction and the direction (x axis) of the edge of the square hole, selective ablation of the crystal silicon surface periodic micro-nano structures is achieved. Compared with existing methods, the method has the advantages that surface processing precision and efficiency are improved effectively, and efficient and accurate form control of the surface periodic micro-nano structures is achieved.

The invention discloses a novel all-optical type laser light pump magnetometer and a realization method thereof. The method comprises the following steps: putting a weak-magnetic-field probe into a magnetic field to be detected at a constant temperature; regulating two laser device control circuits respectively to ensure that two laser frequencies are subjected to energy level transition resonance with a D1 line and a D2 line of alkali metal atoms; regulating angles of a half-wave plate optical axis, a quarter-wave plate optical axis and respective laser polarization to ensure that two beams of laser form round polarization with the polarization phase difference of 180 degrees; regulating two laser devices, a half-wave plate, a polarization beam splitting prism and a quarter-wave plate to ensure that the two beams of laser are completely overlapped on the weak-magnetic-field probe; detecting the laser frequency and laser subjected to the energy level transition resonance with the D1 line of the alkali metal atoms by a photoelectric converting device; and acquiring and carrying out signal processing on a detected light intensity value through data acquisition and processing equipment to obtain magnetic induction intensity B of a magnetic field to be detected. The novel all-optical type laser light pump magnetometer has the advantages of simplicity in operation and no electromagnetic interferences and can realize all-optical property of the weak-magnetic-field probe.

The invention relates to a method for controlling the shape of a femtosecond laser induction crystalline silicon surface micro-nano structure. According to the method, on the basis of control over the geometrical shape of a single-point femtosecond laser induction crystalline silicon surface periodic micro-nano structure, direct-writing line width is adjusted and regulated through control over the linear polarization direction of the femtosecond laser and the laser direct writing direction, the minimum line width surface periodic micro-nano structure is obtained when the laser direct writing direction and the linear polarization direction are parallel, and the maximum line width surface periodical micro-nano structure is obtained when the laser direct writing direction and the linear polarization direction are perpendicular. The method has the advantages that through simple adjustment based on laser polarization states and application of a femtosecond laser impulse sequence, the geometrical shape of the femtosecond laser induction crystalline silicon surface periodic structure can be accurately controlled, so that accurate controllable parameters are provided for generation of a femtosecond laser direct-writing induction large-area periodic structure, and the method is suitable for manufacturing femtosecond laser direct-writing accurate induction large-area surface periodic structure.