57 results about "Volume bragg grating" patented technology

The invention relates to the technical field of laser, in particular to a dual-wavelength narrow-linewidth laser output device and method.The dual-wavelength narrow-linewidth laser output device comprises a semiconductor laser unit emitting linearly polarized light beams, and a light beam conversion lens is used for achieving conversion of semiconductor laser fast-axis light beams and semiconductor laser slow-axis light beams; the light beam conversion lens is used for collimating and compressing a semiconductor laser fast axis divergence angle, and the slow axis collimating lens is used for collimating and compressing a semiconductor laser slow axis divergence angle; the linearly polarized light beam is divided into a first light beam and a second light beam through the rectangular prism; the first light beam sequentially passes through a first volume Bragg grating, a first reflector, a half-wave plate and a polarization beam combiner; the second light beam sequentially passes through a second volume Bragg grating, a second reflector and a polarization beam combiner; the dual-wavelength narrow-linewidth semiconductor laser can solve the problems of precise regulation and control and power amplification of the central wavelength of the dual-wavelength narrow-linewidth semiconductor laser, has power expansibility, and realizes improvement of laser power by stacking a plurality of laser units in the vertical direction.

The invention provides a photosensitive glass ceramic with lower visible light absorption loss, which comprises the following components in molar percentage: cation components: 50-65% of Si < 4 + >; 25 to 38% of Na < + >; 2-6% of Zn < 2 + >; 3-9% of Al < 3 + >; 0.001 to 0.1% of Ag < + >; 0.001 to 0.08% of Ce < 4 + >; 0.02 to 0.2 percent of Sb < 3 + >; the negative ion component comprises 88 to 98 percent of O < 2->, 0.001 to 0.09 percent of Sn < 4 + > and 88 to 98 percent of Sn < 4 + >; f-: 2 to 10%; and 0.05 to 2 percent of Br <->. Through reasonable component design, the obtained photosensitive microcrystalline glass is low in visible light absorption loss and can be used for preparing glass elements such as volume Bragg gratings with low optical loss and high diffraction efficiency.

The present invention provides a thin-film dual-pulse-width output laser, comprising: a femtosecond laser; a polarization beam splitting module for splitting the laser pulses output by the femtosecond laser into two laser beams; one of the laser beams is sequentially introduced into a first regenerative amplifier through a first reflector, a first thin-film polarizer, a first Faraday rotator, a first half-wave plate and a first polarizer, oscillated and amplified therein, and then output after dispersion compensation by a first dispersion grating; the other laser beam is broadened to 2.7 ps by a second chirped volume Bragg grating, and then sequentially introduced into a second regenerative amplifier through a second reflector, a second thin-film polarizer, a second Faraday rotator, a second half-wave plate and a second polarizer, oscillated and amplified therein, and then output after dispersion compensation by a second dispersion grating. A laser output method is also provided. Dual-pulse-width lasers can be output simultaneously in the above device and method.

Disclosed herein is a waveguide-based display comprising: an optically transparent substrate; an input grating comprising an emptied periodic structure (EPS) supported by the substrate, where the input grating diffracts light into total internal reflection (TIR) within the substrate; a folded grating including an EPS or a volume Bragg grating (VBG), where the folded grating receives the TIR light and expands the TIR light in a first direction; and an output grating including an EPS or a VBG. The output grating receives the expanded light and outputs the light, and the input grating is spatially separated from the folding grating and the output grating.

According to examples, a display system may include a wearable eyewear arrangement that may include a lens assembly having a projector to propagate display light associated with an image. The lens assembly may also include a waveguide configuration for propagating the display light to an eyebox. The waveguide configuration may include a volume Bragg grating (VBG) component for propagating the display light from a projector to an eyebox. The VBG component may include at least one tilt adjusted grating facilitated by adjustment in an original grating vector (k) direction of a grating by a pre-determined value. The tilt adjusted grating may facilitate to mitigate a rainbow effect observable in a gazing direction of the eyebox. The rainbow effect may be mitigated by modification of a rainbow ghost path away from the gazing direction without affecting propagation of the image pertaining to the display light.

A three-dimensional Bragg grating may include a single colloidal crystal that includes a plurality of repeated layers of material having different refractive indexes. A sample cell for producing a volume Bragg grating may include an internal shape that forms at least one capillary cell having a flat surface and rounded edges. A method of producing a three-dimensional Bragg grating may include: suspending insoluble particles in a host fluid to form a suspension; and exposing the suspension to a sustained microgravity environment.

The invention discloses an optical fiber laser external cavity spectrum synthesis crosstalk elimination method, which relates to the technical field of laser, and comprises the following four steps of: firstly, designing and constructing a spectrum synthesis system model by taking a reflection-type volume Bragg grating (R-VBG) as a beam combiner, and blocking a crosstalk path through R-VBG wavelength selective transmission and diffraction and grid line vertical design; calculating an optimal grating parameter by combining R-VBG loss and diffraction efficiency correlation and multi-parameter internal relation; a steady-state rate equation is deduced based on a three-energy-level system, and a pumping threshold power change rule and an output characteristic expression are obtained; and finally analyzing the influence of light beam characteristics and thermal deformation on diffraction efficiency, determining a threshold value and controlling temperature, and verifying the system performance through experiments. The method can fundamentally eliminate crosstalk, guarantee the quality of the light beam, balance the cost and loss, adapt to a multi-channel scene, and have a remarkable application value in a multi-field high-power fiber laser.

The invention may be embodied in other forms than those specifically disclosed herein without departing from itMulti-kW-class blue (400-495 nm) fiber-delivered lasers and module configurations. In embodiments, the lasers propagate laser beams having beam parameter products of <5 mm*mrad, which are used in materials processing, welding and pumping a Raman laser. In an embodiment the laser system is an integration of fiber-coupled modules, which are in turn made up of submodules. An embodiment has sub-modules having a plurality of lensed blue semiconductor gain chips with low reflectivity front facets. These are locked in wavelength with a wavelength spread of <1 nm by using volume Bragg gratings in an external cavity configuration. An embodiment has modules having of a plurality of submodules, which are combined through wavelength multiplexing with a bandwidth of <10 nm, followed by polarization beam combining. The output of each module is fiber-coupled into a low NA fiber. In an embodiment a kW-level blue laser system is realized by fiber bundling and combining multiple modules into a single output fiber.

The invention discloses a second harmonic bandwidth compression device and method based on a chirped body Bragg grating, and relates to the technical field of high-resolution laser spectrum analysis, and the device comprises a beam splitting module, the chirped body Bragg grating, a focusing lens and a BBO crystal. The beam splitting module is used for splitting incident laser into two paths of fundamental frequency light to obtain transmission fundamental frequency light and reflection fundamental frequency light; the chirped volume Bragg grating is used for performing positive chirp on the transmission fundamental frequency light to obtain positive chirp laser; performing negative chirp on the reflected fundamental frequency light to obtain negative chirp laser; the focusing lens is used for shrinking the positive chirp laser and the negative chirp laser to the center of the BBO crystal; and the BBO crystal is used for performing sum frequency on the positive chirp laser and the negative chirp laser and outputting second harmonic laser with narrow linewidth. The chirped volume Bragg grating is introduced to replace a traditional complex optical element combination, the structure of the bandwidth compression system is simplified, dependence on precise optical path calibration is reduced, and therefore the influence of external interference factors is reduced.

The invention provides a narrow-linewidth high-power output external cavity semiconductor laser, and relates to the technical field of laser. The narrow-linewidth high-power output external cavity semiconductor laser comprises a packaging shell, a gain chip, a collimating lens assembly, an etalon assembly, a volume Bragg grating and a laser output assembly, a cavity is formed in the packaging shell, and the gain chip, the collimating lens assembly, the etalon assembly and the volume Bragg grating are all arranged in the cavity. A volume Bragg grating is adopted as a mode selection feedback element, and a single longitudinal mode can be selected in combination with a gain curve; the etalon assembly is arranged on the laser light path between the collimating lens assembly and the volume Bragg grating, the etalon assembly can improve the Q value of the laser resonant cavity and compress the laser line width, the laser line width can reach the kHz magnitude, the output power can reach tens of mW, and the whole laser has the advantages of being compact in structure, high in stability and high in environmental adaptability.

A wavelength tunable light source based on a Volume Bragg Grating (VBG) receives a broadband light beam and outputs a diffracted light beam. The spectral profile of the diffracted light beam includes a selected waveband of the broadband light beam accompanied by out-of-band features spatially dispersed by the VBG. The light source further includes a wavelength tuning mechanism, such as a Theta-2Theta rotation system, comprising a VBG rotation stage operable to rotate the VBG to change the incidence angle by a VBG rotation angle, and a displacement device configured to change a relative alignment between the light input and the light output paths by twice the VBG rotation angle. The light output path has an opening sized to allow at least a portion of the selected waveband through while substantially blocking the out-of-band features.

The invention provides a semiconductor pump laser based on a volume Bragg grating outer cavity, and the laser comprises a laser packaging housing which is internally provided with a cavity; a backlight detector, a gain chip, a collimating lens and a volume Bragg grating are sequentially arranged in the cavity along a laser light path; a heat sink is also arranged in the cavity, and the volume Bragg grating is arranged on the heat sink; the backlight detector is used for monitoring the back light power leaked from the rear cavity surface of the gain chip and converting the back light power into an electric signal, and the electric signal is fed back to the driving circuit, so that the driving circuit adjusts the driving current based on the electric signal to stabilize the output light power of the semiconductor pump laser; the collimating lens is used for compressing and collimating a fast axis divergence angle and a slow axis divergence angle of a light beam output by the semiconductor pump laser; the heat sink is used for regulating and controlling the temperature of the volume Bragg grating so as to restrain grating periodic thermal expansion and cold contraction caused by temperature rise of the volume Bragg grating.

Method for measuring the frequency of a laser (D1) using a device for frequency stabilization of a laser (D1, D2), comprising a beam path for coupling laser radiation emitted by the laser (D1, D2) onto a frequency-selective element (G1), wherein the frequency-selective element (G1) is temperature-controlled, and the frequency-selective element is a volume Bragg grating, VBG, (G1) with a plurality of grating structures (E) and, prior to coupling the laser radiation into the VBG (G1) via an input facet, a portion of the laser radiation is diverted into a reference beam and the portion of the laser radiation coupled into the VBG (G1) forms a measuring beam, characterized by the fact that An error signal is derived from the intensity of the reference beam and the intensity of the measuring beam after passing through the VBG (G1), the temperature of the VBG (G1) is adjusted via a control loop using the error signal such that a Bragg frequency of the VBG (G1) corresponds to the frequency of the laser (D1) up to an optionally selected, signed frequency difference, and the frequency of the laser (D1) is determined from the set temperature of the VBG (G1) using a known mapping.

The invention relates to a dispersive optical arrangement (50, 51) adapted to vary the group velocity dispersion of a pulsed light beam (10). According to the invention, the dispersive optical device comprises a polarizing cube beam splitter (11), a first variable periodic volume Bragg grating (13) and a first quarter-wave plate (12) having flat and parallel faces, one face of the first quarter-wave plate (12) being attached to the input / output face (23) of the first Bragg grating (13), and the other face of the first quarter-wave plate (12) being attached to the input / output face (23) of the first Bragg grating (13). The first variable periodic volume Bragg grating (13) is photoetched in the material along a plane parallel to the input / output face (23) of the first Bragg grating (13). The other surface of the first quarter-wave plate (12) is integrated with one of the two side surfaces (19, 20) of the polarizing cubic beam splitter (11).

The invention relates to the technical field of lasers, in particular to a semiconductor laser which comprises a first laser module, a first light beam conversion lens, a first slow axis conversion lens, a first volume Bragg grating and a half-wave plate which are sequentially arranged along a first light beam path. The second laser module, the second light beam conversion lens, the second slow axis conversion lens and the second volume Bragg grating are sequentially arranged along a second light beam path; the polarization splitting prism is located at the intersection point of the first light beam path and the second light beam path; the third volume Bragg grating is located on the side, away from the half-wave plate, of the polarization splitting prism; wherein the diffraction efficiency of the first volume Bragg grating is lower than that of the third volume Bragg grating, and the central wavelength of the first volume Bragg grating is the same as that of the third volume Bragg grating. According to the invention, the multi-mode resonance effect can be suppressed, the side-mode suppression ratio can be improved, and the spectral purity after the line width is narrowed can be improved.

A beamsplitter may include one or more volume Bragg gratings (VBGs) within a volume of a material having an input face, where each of the VBGs is formed as planes of refractive index variation with periodicity along a grating vector direction at a non-zero angle relative to a normal vector of the input face, and where the material receives input beam through the input face. At least a portion of the input beam may directed into one or more diffracted beams when a Bragg condition is satisfied for any of the one or more VBGs, and at least a portion of the input beam undiffracted by the one or more VBGs may forms an undiffracted beam. Relative powers in the undiffracted beam and any of the one or more diffracted beams may be adjusted through angular and / or spectral tuning.

The application discloses a kind of based on valley power lockout semi-out cavity linear polarization interference light source and its design method.The device includes laser power supply, laser, heating wire, heat preservation glue, beam splitter BS, PD photocell and laser frequency stabilization system;Design method is crucial in that: the laser is three longitudinal mode semi-out cavity linear polarization helium-neon laser, laser built-in Brewster window, and the key parameters of the laser are calculated by longitudinal mode light intensity coupling model, two side modes can be completely suppressed, form the high proportion valley bottom in light intensity harmonic curve, to facilitate frequency stabilization algorithm identification to realize central longitudinal mode frequency locking.The method of the application can make the output power of the laser reach 2.4mW or more, overcome the shortcomings of traditional double longitudinal mode frequency stabilization interference light source power limitation, improve single mode power conversion efficiency, provide a new type of frequency stabilization technology and new type of interference light source for the rapid development of ultra-precision machining and measurement technology and various fields such as single mode conversion complete, high output power, good wavelength stability.

The present invention relates to a device and a method for frequency stabilization of a laser, in particular to a device and a method for frequency stabilization of a laser based on the spectroscopy of a temperature-stabilized volume Bragg grating (VBG). A device according to the invention for frequency stabilization of a laser (D1, D2) comprises a beam path for injecting laser radiation emitted by the laser (D1, D2) into a frequency-selective element, wherein the frequency-selective element is temperature-controlled, wherein the frequency-selective element is a volume Bragg grating, VBG, (G1) with a plurality of grating structures (E) and, prior to injection of the laser radiation into the VBG (G1) via an input facet, a proportion of the laser radiation is branched off into a reference beam and the proportion of the laser radiation injected into the VBG (G1) forms a measurement beam.

An optical communication system is provided with a sequence of diffraction gratings interposed between an external signal pathway and both an internal transmitting unit and an internal receiving unit. A plurality of diffraction gratings arranged into the sequence define a reciprocal optical directional filter. The diffraction gratings, transmitting unit, receiving unit and external signal pathway are arranged such that the transmitted signals from the transmitting unit are transmitted through the sequence of gratings to the external signal pathway based on the wavelength and angle of incidence of the transmitted signals and the received signals from the external signal pathway are transmitted through the sequence of gratings to the receiving unit based on the wavelength and angle of incidence of the received signals. The gratings can be volume Bragg gratings formed within a solid transparent volume interposed between the external signal pathway, the internal transmitting unit and the internal receiving unit.

The application discloses cerium ion doped germanate glass ceramics containing lithium fluoride nanocrystals and a preparation method thereof, and belongs to the inorganic luminescence field. First, GeO2, LiF, Li2CO3, H3BO3, YF3, La2O3 and CeO2 are used as raw materials, and are uniformly mixed according to a certain stoichiometric ratio, and then the raw materials are put into a reducing atmosphere and high-temperature melted to obtain a precursor glass. Then, the precursor glass is heat-treated to obtain the germanate glass ceramics containing lithium fluoride nanocrystals. Under the excitation of ultraviolet light, the precursor glass and the glass ceramics both present blue light emission of 410 nm. The germanate glass ceramics is simple to prepare, and the light emission intensity is significantly improved compared with the precursor glass. The germanate glass ceramics can be used for preparing a volume Bragg grating (VBG) based on a photo-thermal refractive (PTR) glass, and is further applied to laser system design, three-dimensional display and imaging and optical communication and the like.

A high-power laser system includes at least one high-power laser source outputting a substantially single mode (SM) beam. The SM beam is coupled into a reflective volume Bragg grating (RVBG) made of material which absorbs the SM beam to induce a first thermal lens (TL). Upon reflecting, the beam exits the RVBG through the first TL and is coupled into an optical compensator made from material different from that of the first TL and inducing a second TL. The second TL is configured to have a power opposite to that of the first TL matching to that of the first TL to at least partially compensate heat induced thermal degradation of the reflected beam by the first TL.

Disclosed is a self-optimizing beam combining apparatus and method for semiconductor laser beam quality in the technical field of dense spectral beam combining. The apparatus includes a semiconductor laser array, a fast axis collimator array, a slow axis collimator array, a mirror array, a volume Bragg grating array, and an external cavity mirror. A resonant external cavity is formed between a rear facet of each semiconductor laser and the external cavity mirror; after being diffracted by a volume Bragg grating, a portion of laser light transmitted to the external cavity mirror is reflected back onto the volume Bragg grating by the external cavity mirror; the volume Bragg grating utilizes its spectral selection characteristics to diffract a laser mode satisfying a Bragg diffraction condition into a chip of the semiconductor laser, and mode competition characteristics of the semiconductor laser enhance the laser mode to become a dominant lasing mode.

The invention relates to aligning volume Bragg gratings using a laser head. In some implementations, a collimated beam may be provided at a volume Bragg grating (VBG) of a laser module. The collimated light beam may include light generated by a laser chip of the laser head. The free lasing spectrum of the laser chip of the laser head can cover the reflection peak wavelength of the VBG. The scattered light may be received at a spectral monitor. The scattered light may include scattered light from the collimated light beam after passing through the VBG. The orientation of the VBG of the laser module may be adjusted based on the locked lasing spectrum of the scattered light such that the collimated beam is incident perpendicularly to the grating of the VBG.

Disclosed herein is a waveguide based display including: an optically transparent substrate; an input grating including an evacuated periodic structure (EPS) supported by the substrate, wherein the input grating diffracts light into total internal reflection (TIR) within the substrate; a fold grating comprising an EPS or a volume Bragg grating (VBG), wherein the fold grating receives the TIR light and expands the TIR light in a first direction; and an output grating including an EPS or a VBG. The output grating receives the expanded light and outputs the light and the input grating is spatially separated from the fold grating and the output grating.

In a dispersion compensator and method of use thereof a polarized beam splitter (PBS) reflects a light beam having a first instance of S-linear polarization to a first quarter-wave-plate which passes the light beam in a first direction. A first reflector reflects the light beam back through the first quarter-wave-plate in a second, opposite direction, whereupon the light beam now has a P-linear polarization, through the PBS to a second quarter-wave-plate which passes the light beam in a first direction. A second reflector reflects the light beam back through the second quarter-wave-plate in a second, opposite direction, whereupon the light beam now has a second instance of S-linear polarization, which is reflected by the PBS. The first or second reflector is a chirped volume Bragg grating (CVBG) that reflects spectral components of the reflected light beam at different depths of propagation of said spectral components in the CVBG.

A spectrometer may include a rotated volume Bragg grating (r-VBG) within a volume of a material having an input face, where the r-VBG reflects portions of input light propagating through the input face that satisfies a Bragg condition for wavelengths within a spectral band, where a period of the r-VBG along the grating vector is chirped to vary along the grating vector to provide that the Bragg condition is satisfied for different wavelengths at different depths, and where a spectrum of the input light is spatially resolved in the reflected portions of the input light by the r-VBG. The spectrometer may further include a multi-pixel detector configured to receive the reflected portions of the input light from the r-VBG, where the multi-pixel detector is configured to output spectral data indicative of the spectrum of the input light within the spectral band.

The invention relates to an ultraviolet to communication wave band quantum frequency conversion device which comprises a signal light source, a signal light path, a pump light source, a pump light path, a beam combining unit, a PPLN ridge waveguide, a Fabry-Perot cavity and a volume Bragg grating. The pump light source is connected with the second input end of the beam combining unit through the pump light path, the output end of the beam combining unit is connected with the input end of the PPLN ridge waveguide so that frequency down-conversion can be carried out, light after frequency conversion can be obtained, the output end of the PPLN ridge waveguide is connected with the Fabry-Perot cavity and the volume Bragg grating, and finally the light after frequency conversion is output through the optical fiber. Quantum frequency conversion is achieved through difference frequency interaction of signal light and pump light in the PPLN ridge waveguide, noise filtering is carried out in combination with the Fabry-Perot cavity and the volume Bragg grating, and the background noise level is effectively reduced while high overall conversion efficiency is obtained.

A method includes selecting a period for a volume Bragg grating (VBG) such that a spectral selectivity of the VBG is at least as wide as a spectral width of a broadband light beam that is to be spatially transformed, selecting a desired beam transformation for the broadband light beam, passing a first light beam from a recording light source through an optical device to a volume holographic recording medium where the optical device is configured to induce the desired beam transformation, directing a second light beam from the recording light source to the recording medium, and converging the first light beam and the second beam at a recording angle such that a spatial refractive index modulation profile is recorded in the recording medium that provides the VBG with the selected period, and a phase profile is embedded in the VBG that induces the desired beam transformation for each spectral component within a spectral width of the VBG.

The invention provides a SWaP semiconductor laser, and mainly relates to the field of lasers, the SWaP semiconductor laser comprises an optical fiber coupling module, the optical fiber coupling module comprises a light emitting unit, a shaping unit, a beam combining unit, a coupling unit and an optical fiber output unit 9, the shaping unit comprises a fast axis collimating lens 2, a volume Bragg grating 3 and a slow axis beam expanding collimating lens 4, and the fast axis collimating lens 2, the volume Bragg grating 3 and the slow axis beam expanding collimating lens 4 are arranged in sequence; the slow-axis beam-expanding collimating lens 4 is a hyperboloid cylindrical lens, the working distance between a chip and a conventional slow-axis collimating lens can be effectively shortened by 4 mm, unnecessary optical path space waste is avoided, and the size of the module is reduced.