Method of varying neck diameter of output laser beam at fixed distance from laser
SUBSTANCE: method of varying neck diameter of an output laser beam at a fixed distance from the laser is realised by a device having a laser which emits a beam with neck diameter 2hp1 and a confocality parameter zk1, a two-component optical system which forms, in the initial position of components, an output neck with diameter
EFFECT: enabling formation of a laser beam with a variable neck diameter at a fixed distance from the laser.
The invention relates to a laser technique to the field of optical systems, which converts laser radiation, and can be used in engineering, medicine, instrumentation, optical communication and other fields of science and technology, particularly where it is necessary to form the waist of the beam with a variable diameter at a fixed distance from the laser.
The level of technology
There are various methods of forming the laser beam with variable parameters.
There is a method of changing the position of peredachi laser beam, in which the longitudinal movement of the focusing lens by a set of piezoelectric elements, which is implemented in the device . The use of the device in a limited range only change the position of the waist of a beam of constant diameter. Its disadvantage is the inability to change the diameter of the waist of the output beam. This is because the device uses a special case of conversion of the laser beam focusing lens, when at its input quasiparallel beam with very remote strangulation. In this case, there is a very weak dependence of the diameter of the output of the banners from the position of the focusing lens, which allows to consider the diameter of the constriction is almost constant.
Also known the way the move is of the banners of the output laser beam of constant diameter
The disadvantage of this method is the inability to change the diameter of the waist of the output beam.
The closest in technical essence and the achieved result is the way the permanence of the position and diameter of the output spot upon small variations in the diameter of the entrance banners. This method is implemented in the matching of the laser optical system comprising sequentially installed laser emitting a beam with a diameter banners 2hp1and parameter confocality zk1two-component optical system, each component of which (representing a lens or set of lenses) can move along the optical axis .
However, this method does not allow you to change the diameter of the waist of the output beam, which limits its scope.
Disclosure of inventions
The task of the invention is to develop a method that provides a change in the diameter of the output banners at a fixed distance from the laser.
what does is solved by
that way change the diameter of the constriction of the output laser beam at a fixed distance from the laser, which is realized by a device, comprising sequentially installed laser emitting a beam with a diameter banners 2hp1and parameter confocality zk1two-component optical system forming in the initial position of the components of the output waist diameter of
Brief description of drawings
Figure 1 shows the scheme of a two-component laser-optical system;
figure 2 presents a two-component laser-optical system for changing the diameter of the waist of the laser beam at a fixed distance from the laser;
figure 3 presents the law of the moving components of the laser-optical system;
figure 4 presents the law of variation of the diameter of the output of the banners from the magnitude of the displacement of the first component of a two-component laser-optical system.
The implementation of the invention
The invention consists in using two-component laser-optical system, components of which move on the non-linear law, which provides a constant distance from the original banners laser to the output of the banners and the change in the diameter of the output of the banners. The law of transfer of components takes into account the distinctive properties of laser radiation from the classical radiation and the dependence of the conversion of laser radiation optical elements and systems.
Based on the properties of laser beams and simple mathematical relationships between the parameters of the beam at the input and output DOHC nonintel LOS and its design parameters,
the ratio for diameter
The design parameters of the LOS are
Optical device for a continuous change in the diameter of the waist of the laser beam includes sequentially and coaxially located with the laser source, two LOS, the law of movement which takes into account the parameters of the laser beam and LOS and is determined taking into account the relations (1). When dimensioning LOS, providing the required values of
Because when passing through LOS invariant of the laser beam remains
The device includes a laser 1, a radiation beam which h is by the wavelength λ,
shifting 2 diameter 2hp1located at a distance of d0from the output end of the laser parameter confocality zk1the parameter M2LOS consisting of the first 3 and second 4 moving components, which forms the waist 5 of the laser beam with a diameter of
Continuous change in the diameter of the output waist of the laser beam with a fixed position of the output section of the constriction due to the longitudinal displacement of the LOS components is possible only under certain conditions. These conditions establish a definite link design parameters of LOS and beam parameters of the laser source. She, in turn, determines the displacement of the LOS components. Therefore, for the selected laser source with a known radiation parameters to solve this task allows the optical system, with well-defined structural parameters, the components which are moved according to the agreed law.
A feature of the invention is to use the transformation laws of the laser beam optical elements and systems, analytical St. the bond between the parameters of the laser beam and converts it to a two-component optical system and obtaining conditions ensure the immobility of the output banners with variable longitudinal increase in LOS. Received communication allows you to change the diameter of the waist of the output beam at a fixed distance from the waist of the input beam.
In the initial (zero) position, the design parameters LOS: back focal distance of the first
1) is a longitudinal increase in
2) given the length of the system
When these conditions are met, you must also ensure the physical feasibility LOS, when in the initial position of all components of the longitudinal distance is positive: from the input banners to the first surface of the first component
The design parameters of the LOS in the initial position of the components are original data to determine the law of displacement components, which changes the diameter of the waist of the output beam at a fixed distance from the waist of the input beam. For this components you want to move on nonlinear law s2(s1):
where the value of y is the C the solution of the cubic equation
For current provisions of the LOS components of the optical interval Δ(s1)=Δ0-s1+s2and
The displacement of the second component s2is found from the solution of the above equation for a given displacement of the first component, s1. This cubic equation can have one or three real roots. In the case of the three roots is chosen such the root, which corresponds to the lower plumage is edenia second component.
In the intermediate position of the longitudinal components increased LOS and the diameter of the output banners are determined by the expressions:
The differential linear increase of VOC is equal to:
Implement the method as follows (figure 2). The laser beam 1 with hauling 2 diameter 2hp1sequentially converted components 3 and 4 of the optical system which is formed hauling 5 with a diameter of
The preferred option (example) of the invention for changing the diameter of the waist of the beam from 0.32 mm to 0.08 mm at a fixed distance L=452,75 mm from the laser using laser YAG:Nd3+(λ=1.06 µm, M2=1,05, 2hpl=0.3 mm) is shown below.
The design parameters of the two-component VOC in the initial position of the components have the values given in the table.
|The radii of curvature of the refractive surfaces of the components, mm||Air gaps and the thickness of the lens, mm||The refractive index of the medium at the wavelength λ|
|α01,17, L0=452,75 mm|
Figure 3 presents a plot of the displacement components calculated VOC's, and figure 4 is a plot of the changes in the diameter of the output of the shifting movement of the first component.
Sources of information
RF patent 2413265, IPC G02B 27/16 published: 27.02.2011.
RF patent 2411598, IPC G11B 7/125, G02F 1/29, H01S 3/10, published: 10.02.2011.
RF patent 2435182, IPC G02B 27/09 published: 27.11.2011.
Pakhomov I.I., Tsibulya A.B. Calculation of optical systems of laser devices. M.: Radio and communication, 1986. 152 C.
How to change the diameter of the constriction of the output laser beam at a fixed distance from the laser, by the device, comprising sequentially installed laser emitting a beam with a diameter banners 2hp1and parameter confocality zk1two-component optical system forming in the initial position of the components of the output waist diameter of
SUBSTANCE: optoelectronic amplifier has a turned semitransparent mirror, two turned reflecting mirrors, a radiation source, two optoelectronic converters and two correcting lenses. The optical output of the first correcting lens is connected through a first optoelectronic converter to the optical input of the second correcting lens. The device includes a second amplifier, a third correcting lens and a third turned reflecting mirror, having an optical input and an optical output respectively connected through the second turned reflecting mirror, through the third correcting lens to the optical output of the second correcting lens and through the first turned reflecting mirror to the first optical input of the turned semitransparent mirror. The first optical output, second optical input and second optical output of the turned semitransparent mirror are respectively connected to the optical input of the first correcting lens, the optical output of the radiation source and the optical input of the second amplifier.
EFFECT: high light amplification.
SUBSTANCE: beam scanning laser has a laser radiation source, a resonator through one of the optical elements of which a scanning beam comes out, a laser radiation amplifier, light modulators, retarders and polarisation dividers inside the resonator, as well as at least one optical system which returns laser radiation reflected from one of the polarisation dividers into the resonator. The laser radiation source lies outside the resonator; the resonator is based on an annular scheme in which input of radiation from the radiation source and output of the scanning beam is provided through the polarisation dividers which also act as mirrors and the resonator; the optical system gives angular displacement of the laser radiation returned into the resonator, which is reflected from one of the polarisation dividers in the resonator.
EFFECT: high power and repetition frequency of laser beams.
4 cl, 2 dwg
SUBSTANCE: apparatus for differential control of population inversion of laser medium of a pulsed laser based on the kinetics of increase in spontaneous emission power during pumping includes an optoelectronic converter, the input of which is connected to a spontaneous emission power coupler of the laser medium; a controller with an input ADC, for receiving, during intervals between pulses, and time-differentiation of the output signal of the optoelectronic converter, calculating the ratio of two maximum amplitudes, comparing the value of the ratio with a table value and controlling actuating devices using a DAC. The control apparatus also has a first actuating device - a pumping device which varies the pumping level up to switching off in order to protect from optical breakdown and a second actuating device - a master oscillator, which generates an input starting radiation pulse which resets population inversion of the medium to the initial state.
EFFECT: enabling control of population inversion of a laser medium by differential control of a tapped arbitrary part of the spontaneous emission power without the need to calibrate the tapping factor.
2 cl, 6 dwg
SUBSTANCE: Q-switched laser consists of two end mirrors and two auxiliary mirrors. Between the first end mirror of the cavity and the active element there is an acoustooptical modulator, and in front of the second end mirror there is one or more nonlinear crystals or any transparent material having Kerr-type nonlinearity. The first end mirror, modulator, active element and one of the auxiliary mirrors lie in one arm of the optical cavity and the other auxiliary mirror, one or more nonlinear crystals or any transparent material having Kerr-type nonlinearity and the second end mirror lie in the other arm of the cavity. The first end mirror is in form of a concave sphere of radius R1; the centre of the modulator lies at a distance equal to the radius R1 from the reflecting surface of the first end mirror, and a diaphragm is further placed between the second end mirror and the one or more nonlinear crystal or transparent material having Kerr-type nonlinearity. The operating frequency f of the modulator is equal to (or is a multiple of) half the intermode interval 2f of the laser (2f=c/2L, where c is the speed of light, L is the length of the cavity), and the modulator switching frequency determines the pulse repetition frequency Q-switch (for example, selected in a range from 1 to 100 kHz).
EFFECT: improved output characteristics.
2 cl, 2 dwg
SUBSTANCE: laser radiation modulator has a laser, a relief diffraction grating with a rectangular profile, which reflects a beam of the modulated laser radiation, the depth of which is greater than a quarter of the wavelength of the modulated laser radiation, and a platform which is connected to an electromechanical vibrator mounted on a fixed base. The relief diffraction grating is made from plates which are formed into stationary groups and groups of movable plates capable of back-and-forth movement, placed in spaces between plates of the stationary group, the ends of which are shifted with respect to the ends of the stationary group in a direction which is perpendicular to surfaces facing the laser. The stationary group is connected to the base by a precision adjustment mechanism, and the group of movable plates is placed on the platform which is connected by an elastic suspension to the base and the electromechanical vibrator. The ends of plates facing the laser beam have a flat surface which reflects laser radiation.
EFFECT: high accuracy of positioning a laser beam.
SUBSTANCE: pulsed laser radiation source has at least one pulsed laser, an optical means for summation of radiation and a focusing system. The source further includes a driving generator whose output is connected to the input of the pulsed laser, and the output of the pulsed laser is optically connected in series to an optical switch, a matching unit, an optical delay means and the optical means for summation of radiation and then further with the focusing system, wherein the output of the driving generator is connected to the control input of the optical switch.
EFFECT: high output optical power of laser radiation pulses.
SUBSTANCE: device includes an optical amplifier which includes an optical amplifying medium (11) which optically amplifies light to be amplified, and a transparent medium (12), through which the light to be amplified passes multiple times; and an energy source (30) which supplies energy for exciting the optical amplifying medium (11). The set of components, including the optical amplifying medium (11) and the transparent medium (12) of the optical amplifier, are combined. The transparent medium (12) has the shape of a rectangular parallelepiped or a polygonal column having five or more sides, and light (11) incident on the transparent medium (12) is completely reflected by surfaces of the walls of the transparent medium (12), moving and rotating inside the transparent medium (12).
EFFECT: smaller size, high power and stabilisation of the device.
20 cl, 33 dwg
FIELD: radio engineering.
SUBSTANCE: method is implemented in the following way. Owing to selection of curvature radii of completely reflecting and output resonator mirrors and distances between resonator mirrors, laser emission beam parameters are adjusted by setting the specified ratio between width of resonator stability zone and focal power value of thermal lens, which is induced in active element by pumping radiation. Then, laser emission beam is focused on the processed material. When it is necessary to change the material processing mode, pumping power is changed at maintaining the specified ratio between width of resonator stability zone and focal power value of thermal lens. In order to maintain the specified value of the ratio, curvature radius of completely reflecting mirror is changed and it is installed at the specified distance from active element.
EFFECT: improvement of operating characteristics of laser processing of materials with various properties.
2 cl, 4 dwg
SUBSTANCE: apparatus includes, arranged in series on an optical axis, a mutual polarisation rotator which rotates the polarisation plane of transmitted radiation by an angle φ and a compensating optical element placed behind an absorbing optical element. The compensating element is an optical element having, for the same parameters of laser radiation, thermally induced depolarisation γ1 approximately equal to γ0: γ1 (P1, Q1, k1, ξ1, α1, L1, W) ≈ γ0 (P0, Q0, k0, ξ0, α0, L0, W), where P and Q are thermo-optical parameters of the element, k0 is the thermal conductivity coefficient of the element, ξ0 is the optical anisotropy parameter of the material of the element, α0 is the absorption coefficient of the material of the element, L0 is the length of the element, W is the laser radiation power. At least one of said parameters, from which γ1 depends, is not equal to the corresponding parameter γ0, and angle φ of the mutual polarisation rotator and the distinctive parameters of the compensating element are determined by the selection of the material of the compensating element and the condition for minimum total thermally induced depolarisation in the absorbing element-mutual polarisation rotator-compensating element system.
EFFECT: possibility of compensating for thermally induced depolarisation in any predetermined laser absorbing optical element.
4 cl, 3 dwg
SUBSTANCE: source has a laser diode (LD) mounted on a wide optical resonator (30, 82), lying between two reflecting surfaces (92, 48) and a filter (44, 86) for selecting modes on the optical path in the resonator. The wide resonator (82) has the following devices arranged on the optical path: an optical device (94) having a polariser (100) which transits 100% linear polarisation of the beam Fd generated by the laser diode, having an initial polarisation angle θ0 equal to 0°, a device (102) for turning the polarisation plane, which turns the polarisation plane of the beam (Fcl) coming out of the polariser by a given angle θ1, a polarisation divider (104) for dividing the beam (Frt) coming out of the device for turning the polarisation plane, an optical device which prevents the return of the reflected beam (Freturn), specifically the reflected useful beam (Fu) to the laser diode (LD). Said polarisation divider lies in the resonator at such an angle that its transmission axis (tt') is directed at an angle (-θ1) of opposite sign and the same value as the polarisation angle of the beam (Frt) coming out of the device (102) for turning the polarisation plane.
EFFECT: reduced width of the spectral line and reduced load on the laser diode while maintaining power at the output of the source.
11 cl, 5 dwg
SUBSTANCE: collimating optical system has a lens and two rectangular prisms arranged in series on a beam path. The edges of the refracting dihedral angles of the prisms are directed perpendicular to the plane of the semiconductor junction. The refracting angles of the prism are the same and are selected in the range of 20…42°, α is the angle of incidence of radiation beams on the prism and β is the refracting angles of the prism, selected based on the relationship: where n is the refraction index of the material of the prism. The focal distance of the lens F is selected based on the relationship where φ is the required radiation divergence; a|| is the size of the emitting region of the semiconductor laser in a plane which is parallel to the plane of the semiconductor junction.
EFFECT: reduced size of optical-electronic devices using semiconductor laser radiation while preserving quality.
SUBSTANCE: matching laser optical system is configured to ensure constancy of the size and position of the output waist during variation of the size of the input waist and comprises a laser, the beam of which, with a confocal parameter Zk, has an initial waist with radius varying in the range [hp,min; hp,max] with nominal value hp0, as well as an optical system consisting of first and second mobile components configured to form in the plane of the irradiated object, the output waist of the laser beam with constant size hp and at a constant distance L from the initial waist.
EFFECT: ensuring constant size and position of the output waist relative the initial waist.
FIELD: physics, optics.
SUBSTANCE: method involves formation of an initial converging laser beam and converting it to a beam with polarisation mode distributed on the aperture using a birefringent element, polarisation filtering of the beam with a polariser, adjustment of the spatial profile of intensity of the beam by rotating the birefringent element, or the polarisation vector of the initial converging beam, or polariser. The birefringent element is a birefringent plate lying between telescopic lenses and enables creation of a non-identical angle between the axis of the birefringent plane and the wave vector of an extraordinary ray for identical angles of deviation of the rays from the axis of the beam, which enables formation of a parabolic spatial profile of intensity after polarisation filtering, identical in one of the planes along the direction of propagation and all planes parallel to the said plane on the entire aperture of the beam.
EFFECT: formation of a laser beam with a parabolic spatial profile of intensity with controlled level of intensity of radiation at the centre of the parabola, as well as controlled position of the parabola on the aperture of the beam.
SUBSTANCE: device has a laser beam source, a transmitting element in form of a tube placed on the path of beam and filled with air at atmospheric pressure, and a recording unit. On both ends of the tube there are optically transparent end caps which reduce uncertainty of the spatial coordinates of the axis of the beam at the output of the tube. The tube with end caps acts as a high-Q cavity resonator and under the effect of external broad-band (white) noise, a standing wave having natural frequency and overtones is initiated in the tube, under the effect of which equalisation of optical refraction coefficients of air inside the tube takes place.
EFFECT: maximum spatial localisation of the laser beam to enable its use as an extended coordinate axis.
1 dwg, 1 tbl
SUBSTANCE: optical system includes two channels, each of which consists of a collimating lens 1 and a refracting component 2, and a summation component 3, fitted behind refracting components 2 of both channels and having a surface with a polarisation coating. The channels are turned such that, the radiation polarisation planes of the lasers are mutually orthogonal and their optical axes intersect on the surface of the summation component with polarisation coating and coincide behind the summation component. The polarisation coating completely transmits radiation polarised in the plane of incidence on the given surface, and completely reflects radiation polarised in the perpendicular plane. Focal distances of the lenses, size of the illumination body in the semiconductor junction plane and angular divergence of the beam collimated by the lens are linked by expressions given in the formula of invention.
EFFECT: increased power density and uniformity of angular distribution of radiation intensity with minimum energy losses on components of the optical system and minimal overall dimensions.
9 cl, 6 dwg, 4 ex
SUBSTANCE: proposed method aims at producing light homogenisation device comprising at least one substrate (1) that features at least one optically functional surface with large amount of lens elements (2) that, in their turn, feature systematic surface irregularities. At the first stage aforesaid lens elements (2) are formed in at least one optically functional surface of at least one substrate (1). At the second stage at least one substrate (1) is divided into at least two parts (3, 4). Then at least two aforesaid parts of substrate (1) are jointed together again, provided there is a different orientation of at least one of aforesaid parts (4). The said different orientation of one of at least two parts allows preventing addition of light deflections caused by aforesaid systematic surface irregularities after light passage through separate lens elements.
EFFECT: higher efficiency of light homogenisation.
16 cl, 8 dwg
FIELD: physics; optics.
SUBSTANCE: invention is related to method for control of partially coherent or incoherent optical radiation wave or waves field intensity distribution at final distance from its source or in far-field region and device that realises the stated method. At that in realisation of the stated method, optical element is used, which is installed in mentioned field and comprises diffraction grid arranged as periodical by one or two coordinates x, y that are orthogonal in relation to direction of falling optical radiation distribution, with the possibility to separate the mentioned field into partially colliding beams aligned in relation to directions of diffraction order directions.
EFFECT: even distribution of intensity in multimode laser beam with the help of diffraction element.
11 cl, 8 dwg
FIELD: the proposed invention refers to the field of technical physics and may be used in quality of a plane converter of electromagnetic radiation into a coherent form.
SUBSTANCE: the arrangement has a substrate on which there are two adjoining topologies having common axles of fractalization and a center, the modules of each of them are similar to the corresponding modules of the first adjoining topology. At that additionally on the substrate the third adjoining topology whose radius R3 of the basic circumference equals R1√3 is formed.
EFFECT: increases bandwidth of the received coherent radiation and also increases the degree of radiation coherence.
4 cl, 8 dwg
FIELD: technical physics, possible use for expanding arsenal of devices for transformation of electromagnetic field to coherent form.
SUBSTANCE: the device contains semiconductor substrate, on which in slits self-affine topology is formed on basis of fractalizing module, consisting of a set of circles with radius R, where first circle is geometrical locus of positions of centers of other circles of the set with equal distances between adjacent circles, center of first circle coincides with the center of circle with radius equal to 2R and is the center of the whole self-affine topology, and fractalization of module occurs along axes, passing through the center of the first circle and centers of other circles of the set. Self-affine architecture is grounded.
EFFECT: creation of planar source of device for transformation of electromagnetic radiation to coherent form.
FIELD: the invention refers to optical technique.
SUBSTANCE: the lens has in-series installed the inner down the way of radiating of light diode, and the exterior surface. The inner surface of the central zone adjacent to the axle of the lens, has an optical force providing transfer of the image of the radiating site of the light diode on more remote distance from the exterior surface. The exterior surface has a form of a funnel turning with its peak from the radiating site of the light diode. The profile of the exterior surface is such that at first interaction of radiating with the exterior surface full inner reflection takes place and at the second interaction of radiating with the exterior surface refraction of light takes place in the direction primarily perpendicular to the optical axle of the lens.
EFFECT: reduces part of the radiating flow emergent of the forming lens near its axle, increases intensity of emergent beam of light and provision of more uniform distribution of intensity of light falling on the screen.
SUBSTANCE: laser lighting device for lighting band or linear portion S on object B, primarily on sheet material includes source 2,2' of laser radiation, optical system 4 for expanding the beam, spatially expanding fan-shaped laser beam L2 in two mutually perpendicular directions, and also an astigmatic lens 6, upon which fan-shaped laser beam L2 falls, focal distance f2 of which is shorter than distance A from beginning of fan-shaped laser beam L2 and focal plane of which lies on object B or close to it.
EFFECT: generation of a beam on surface, with high intensiveness, with low light losses; human eyes are protected from laser radiation.
8 cl, 3 dwg