Adjustable-beam-wavelength pulsed solid state laser system

FIELD: pulsed solid state lasers; high-power nanosecond radiation pulse generation.

SUBSTANCE: proposed system has two solid state lasers using electrooptically Q-switched cavity and parametric light oscillators. There are master lasers and amplifiers. Two active elements of master lasers having polished side surface are placed in single-lamp light. Two active elements of amplifiers are placed in other single-lamp light. Each amplifier is connected in double-pass ring circuit. The latter has first polarizer, polarization plane 90 deg. shifter, active element, second polarizer, first rotary mirror, telescope, dual-beam refraction plate, and second rotary mirror, all arranged in tandem.

EFFECT: enhanced stability of radiation pulse parameters and operating reliability, reduced mass and size.

1 cl, 1 dwg

 

The present invention relates to a pulsed solid-state lasers with electro-optical q-switched resonator with frequency conversion of the radiation in a parametric light generators and can be used to produce powerful nanosecond pulses of laser radiation, continuously tunable wavelength in the middle (˜1.6 ám) and average (˜3 μm) infrared spectral range in lidar systems environmental gas analysis of the atmosphere.

Among the methods of laser remote gas atmosphere, allowing you to get complete information about the presence of hydrocarbons, primarily methane, extended paths along pipelines or in areas where there are storage facilities, the most promising is the method of differential absorption.

To implement this method requires tunable in wavelength laser system with radiation at a wavelength of λinfalling in a narrow absorption line of the gas being detected, and with radiation at a wavelength of λoutnot falling within the absorption line, but close to λit. Then when reflected from the underlying surface in the event of signal attenuation at a wavelength of λinit is possible to judge the presence of this gas. To detect other gas (ethane, propane, BU the Ana and so on) you want to rebuild wavelengths λ inand λoutin accordance with its absorption spectrum.

Known single-channel laser system on the solid-state laser AHT:Nd with parametric light generators on the basis of the nonlinear element of the crystal LiNbO3tunable wavelength radiation [1]. However, this system cannot work in the composition of the mobile complex, because the tuning of the wavelength of radiation and the measurement of each wavelength requires some time.

To obtain operational information for remote gas analysis of the atmosphere using mobile systems, posted by car or helicopter, from the laser system requires that she worked in a pulsed mode and was dual channel.

Closest to the technical essence of the present invention is a dual-pulse solid-state laser system for automobile and aircraft lidar system for a gas atmosphere consisting of two synchronously emitting pulsed lasers AHT:Nd converting the wavelength of the pump radiation λn=1064 nm in a parametric light generators in LiNbO3detecting the presence of methane at distances up to 500 m [2]. The search methane is at idle wave radiation ASG (λx)in=392,2 nm, falling in line pohlad the deposits of gas. In the second channel pulses of radiation with a wavelength (λx)out=3391,2 nm, not falling within the absorption band of methane and water vapor, are shifted in time relative to the pulses in the first channel by the time interval ˜20 μs. Laser system emits two channels of pulse duration and repetition rate of 25 Hz, which allows motion of the complex to process incoming information.

The most important requirements to the parameters of the laser pulses is the pulse energy at a wavelength of λx(Eλx≥1 MJ), which determines the range of the complex, and the width of the emission spectrum of (Δ1/λx≤3.5 cm-1), which should not exceed the line width in the absorption spectrum of methane.

These requirements in practice define the principle of the dual laser system. Thus, each channel is single-mode sets the laser AHT:Nd, generating radiation with a narrow spectrum width and the diffraction divergence, dwupokojowy amplifier, which increases the energy of the pump pulses λn=1064 nm to a value of ≅100 MJ, and resonator parametric generator light on LiNbO3with the lasing signal waves with λwith=1600 nm and single wave λx≅3300 nm.

The main disadvantage given the Oh system is increased sensitivity of the energy parameters of the pulses of the master laser to the energy of the pump pulses, due to the need of the choice of the working point on the energy of the pump pulses near the generation threshold, as it is near the threshold the spectral width of the pump radiation is the most narrow, and the duration of the pulses is large enough to provide the necessary width of the emission spectrum of ASG (Δ1/λx=3.5 cm-1). Therefore, small variations in the energy of the pump pulses in the direction of decreasing, for example due to natural degradation of the flashlamp during operation, lead to a strong instability of the pulse energy emission λxand even ruin the generation of CBC, which also operates close to its threshold.

At small deviations of the energy of the pump pulses in the direction of increasing, for example due to the instability of the energy of the pump pulses or errors in the choice of the working point, a sharp increase of the pulse energy of the pump radiation Eλnleading to optical breakdown of a surface element of LiNbO3and , therefore, to irreversible degradation of the parameters of the radiation pulses PACS.

Other disadvantages of the known system should include large weight and size, due to the application of the principle of replication "two channel two laser"that has led to the need to use 4 power tubes and 2 cooling unit WWS is Fort worth.

The present invention is to improve the stability of the parameters of the pulses of radiation and increase the reliability in operation of the laser system, as well as reducing its weight and size.

To solve the problem in two-channel solid-state laser system with a tunable wavelength, consisting of two solid-state lasers with parametric light generators, applied lasers, consisting of sets of lasers and amplifiers, and two of the active element specifies lasers with polished lateral surface placed in one illuminator, and two of the active element of the amplifier is placed in the second one illuminator, each amplifier is made for two-pass ring circuit comprising serially arranged first polarizer rotator polarization plane by 90°is an active element, a second polarizer, the first rotary mirror, telescope, birefringent plate and the second rotary mirror.

The application in the master laser active elements with polished lateral surface allowed the stabilization of the energy parameters of pulses defining lasers near threshold when placing active elements in one of the illuminator and the application of the scheme of the two-pass amplifier to lavage type with built-in attenuator on the basis of the birefringent plate and the first polarizer allowed to place the active elements of the amplifier in one one the illuminator.

The drawing shows a diagram of the device.

Two resonator two sets of lasers formed deaf mirrors 1, 2 and a common outlet, a partially transparent mirror 3. The polarizer 4 is a plate with a multilayer dielectric coating, polarizes the radiation in the plane of the drawing. Electro-optical elements of the crystal LibO35, 6 can change the q factor of the resonator when a voltage is applied to the control electrodes. The active elements 7, 8 of the yttrium aluminium garnet with neodymium (YAG:Nd) of cylindrical shape size ⊘3×60 mm is placed in one illuminator 9, with the side surface of the active elements 7, 8 is polished (processed 10 class). For the output mirror 3, there are two amplifier-based active elements of the YAG:Nd a cylindrical shape size ⊘6,3×100 mm, each of which has a two-pass ring circuit. Each amplifier contains a first polarizer 10, the rotator of the plane of polarization by 90° on the basis of the optically active crystalline quartz 11 (12), the active element 13 (14), the second polarizer 15, the first rotary mirror 16 (17), the telescope of the negative lens 18 (19), and a positive lens 20 (21), birefringent plate λ/4 22 (23), the second rotary mirror 24 (25). Two of the active element 13 and 14 placed is in one illuminator 16.

After turning mirrors 27, 28 (29, 30) are parametric light generators, each of which contains a resonator formed by parametric mirror 31 (32), transparent for radiation with λn=1064 nm and deaf for radiation λwith=1600 nm, and parametric mirror 33 (34), transparent for radiation with λn=1064 nm and λx=3300 nm, partially transparent for radiation with λc=1600 nm, and the element of the crystal LibO335 (36) size 12×14×40 mm

To obtain efficient parametric generation of light you must use the crystals LibO3with a high degree of longitudinal and transverse homogeneity. In the process of selecting items for their uniformity is controlled by a special method.

The proposed device operates as follows.

In the pulse-periodic mode during each pumping pulse lamps lights, each of which is a load for the corresponding power supply unit, when closed electro-optical gates of the resonator formed by the polarizer 4, the electro-optical elements 5, 6 and mirrors 1, 2, all the active elements 7, 8, 13, 14, the accumulation of inverse population.

Since the side surface of the active elements of the master laser is polished and, therefore, good for reflecting rays on the angles of total internal reflection, in the active elements after a certain time (˜100 μs) after the start of the pumping pulse generation develops the so-called internal modes. The intensity of the internal modes of the maximum in the volume between the surface of the active element and the virtual surface of the cylinder of the same length as the active element, but the section of smaller diameter d=Dn-1where D is the diameter of the cross-section of the active element, n is the relative refractive index (crystal - coolant).

Therefore, in this peripheral area of the volume element, the gain continues to grow over time. In the Central part of the active element growth gain continues, resulting in the cross section of the element of the so-called active soft diaphragm. Active soft aperture has a high gain in the center section with abrupt, but gradual decline on the boundary of a virtual cylinder with diameter d. This distribution provides the first sets the laser generating transverse fashion TEMooqwhen enabled, the q of the resonator formed by the mirrors 1, 3, by filing a pulse of high voltage to the electrodes of the electro-optic element 5 with the control unit stopper BUZ-1.

By controlling the time of inclusion of q by selecting the delay time of the pulse run the UZ-1 relative to the beginning of the pulse tube pump, you can find the necessary level of energy monopulse single-mode radiation.

When increasing the pump energy by increasing the energy of the pumping pulse En=CU2/2, where C is the capacitance of the discharge capacitor, U - predrazenou voltage on the capacitor, is increase the intensity of internal modes in the active element and, consequently, to increase their influence in the Central region of the active element due to rays that fall in the center of the scattering volume.

As a result, the growth energy of the pump pulses does not increase energy monopulse radiation. Thus, there is the possibility of stabilizing the energy parameters of monopulse radiation level with a wide dynamic range. The level depends on the moment of switching the resonator q factor and can be chosen close to the near threshold values.

When enabled, the resonator q factor of the second master laser using BUZ-2 through time ˜10 μs after switching the resonator q factor of the first reference laser of the second sets the laser also generates monoenoic radiation with a spatial structure corresponding to the mode TEMooqat the energy close to the energy of monopulse radiation of the first laser, since the lifetime of metastable ions Nd3+is 30 μs.

Next, the single-mode emission of two sets of lasers is directed through two channels in two amplifiers, active elements which under the action of one of the flashlamp at which the maximum inverse population at the time, similar to the generation of monopulse radiation sets of lasers.

Passing the first polarizer 10 and the rotator 11 of polarization at 90°the radiation of the first master laser changes the plane of polarization from horizontal to vertical, is amplified in the active element 13 and is reflected from the second polarizer. Then the radiation is directed by the mirror 16 in a telescope with lenses 18, 20 and partially depolarized in the plate λ/4 22. After reflection by mirror 24 radiation on a vertical plane of polarization of the second time passes rotator 11, becoming polarized in the horizontal plane, is amplified in the active element 13, passes through the polarizer 15 and through the mirrors 27, 28 is sent to ASG.

The radiation of the second master laser is amplified in a similar way in the second amplifier and sent to the ASG.

Since the required parameters of the radiation pulses PACS can be obtained when defined with great precision power parameters of pulse duration λn(between threshold PACS and radial strength), the final adjustment of energy pulses with BB; nby using rotation of the birefringent plates 22, 23, which, together with the polarizer 10 play the role of smooth attenuator with attenuation from 1 to 2.

To narrow the generation spectrum of the radiation CBC requires that the divergence of the radiation with λnin each channel was minimal. This condition is achieved by changing milesovka distance corresponding telescope, which compensates the influence of thermal lens in the active element of the amplifier to the curvature of the phase front of the radiation.

The most important features of the proposed device is a two-channel solid-state laser system with a tunable wavelength are:

1) short-term and long-term stability of the energy parameters of the pulses driving the laser in the near threshold energy region of the pulse tube of the pump, thereby creating a compact dual setpoint laser based on one illuminator with single power supply;

2) the possibility of high-precision adjustment of the energy parameters of the pulses and the divergence of the radiation with λnafter amplification in the amplifier based on a compact two-element one illuminator with a single power supply that together with claim 1. improves the reliability of the system;

3) compactness and less weight with the system due to the reduction in two times in comparison with the prototype of the number of emitters, power supplies and cooling systems.

Literature

1. Remieres, "Laser remote sensing", M., "Mir", 1987, s.

2. RF patent №2086959, G 01 N 21/39, 21/61 prototype.

Dual-pulse solid-state laser system with Perestroikas wavelength radiation, consisting of two solid-state lasers with parametric light generators, characterized in that the lasers consist of sets of lasers and amplifiers, and two of the active element specifies lasers with polished lateral surface placed in one illuminator, and two of the active element of the amplifier is placed in the second one illuminator, each amplifier is made for two-pass ring circuit comprising serially arranged first polarizer rotator polarization plane by 90°is an active element, a second polarizer, the first rotary mirror, a telescope, a birefringent plate and second rotary mirror.



 

Same patents:

FIELD: laser engineering; emission-line narrowing devices built around diffraction grating.

SUBSTANCE: emission-line narrowing device has diffraction grating, master working side of diffraction grating, chamber for accommodating at least mentioned diffraction grating, helium source for blasting mentioned chamber, beam expanding device that functions to expand mentioned laser beams, turning gear for guiding mentioned expanded beam to working side of diffraction grating to select desired wavelength range from mentioned expanded beam. Method for regulating laser frequency dispersion involves guiding of gaseous helium flow to working side of diffraction grating; in the process pressure of blast gas is reduced to cut down optical effects of hot gas layer.

EFFECT: minimized thermal distortions in narrow-line lasers generating high-power and high-repetition-rate beams.

15 cl, 12 dwg

FIELD: laser engineering.

SUBSTANCE: proposed device has pumping unit, resonator, semiconductor mirror, output lens, and input lens. Optical output of pumping unit is optically coupled with resonator whose optical output is coupled through semitransparent mirror with optical input of output lens. Newly introduced in device are optically controlled transparent amplifier, additional light source whose frequency exceeds resonator radiation frequency, three reflecting mirrors, and one more semitransparent mirror. Resonator optical output is coupled in addition through semitransparent mirror with first optical input of optically controlled transparent amplifier whose second optical input is coupled through additional semitransparent mirror with output of additional light source and optical output is coupled through three reflecting mirrors, additional semitransparent mirror, and second lens with resonator for its additional pumping.

EFFECT: enhanced power without increasing device mass.

1 cl, 1 dwg

Tunable laser // 2244368

FIELD: laser engineering; tunable lasers.

SUBSTANCE: laser has case accommodating cavity incorporating active medium, output mirror, and spectral-selective element in the form of diffraction grating. Grating set up in bezel is connected through first adjusting mechanism to loose end of moving lever. Other end of the latter is locked in position by means of spherical supports in U-shaped flange connected through second adjusting mechanism to laser case. Loose end of moving lever is kinematically coupled with micrometer screw. Provision for individual and independent adjustment of dispersion plane of diffraction grating and axis of revolution of moving lever, with this position being maintained in the course of operation, ensures steady and reliable functioning of laser under all mechanical and environmental impacts.

EFFECT: enhanced, reliability, reproducibility and precision of wavelength selection.

1 cl, 3 dwg

The invention relates to laser technology and can be used in the development of tunable radiation waveguide lasers used in medicine, monitoring of the atmosphere, optical radars, target devices, and precision materials processing

The invention relates to a managed laser technology and can be used to build managed laser resonators of various types, including those with controlled output power, receive continuous laser pulse-periodic modulation mode in a wide range and with different amplitude and to increase the power output and peak intensity of different lasers

The invention relates to the field of laser technology, specifically, to systems fiber-optic communication

The invention relates to laser optics and can be used when working with solid-state and gas lasers used in laser technology, laser medicine, research

The invention relates to a pulsed solid-state lasers with lasing at two wavelengths and can be used to obtain the powerful pulses of laser radiation in the near infrared range, including safe to the human eye

The invention relates to techniques for frequency stabilization and can be used to generate a timeline

The invention relates to techniques for frequency stabilization and can be used to generate a timeline

Tunable laser // 2244368

FIELD: laser engineering; tunable lasers.

SUBSTANCE: laser has case accommodating cavity incorporating active medium, output mirror, and spectral-selective element in the form of diffraction grating. Grating set up in bezel is connected through first adjusting mechanism to loose end of moving lever. Other end of the latter is locked in position by means of spherical supports in U-shaped flange connected through second adjusting mechanism to laser case. Loose end of moving lever is kinematically coupled with micrometer screw. Provision for individual and independent adjustment of dispersion plane of diffraction grating and axis of revolution of moving lever, with this position being maintained in the course of operation, ensures steady and reliable functioning of laser under all mechanical and environmental impacts.

EFFECT: enhanced, reliability, reproducibility and precision of wavelength selection.

1 cl, 3 dwg

FIELD: laser engineering.

SUBSTANCE: proposed device has pumping unit, resonator, semiconductor mirror, output lens, and input lens. Optical output of pumping unit is optically coupled with resonator whose optical output is coupled through semitransparent mirror with optical input of output lens. Newly introduced in device are optically controlled transparent amplifier, additional light source whose frequency exceeds resonator radiation frequency, three reflecting mirrors, and one more semitransparent mirror. Resonator optical output is coupled in addition through semitransparent mirror with first optical input of optically controlled transparent amplifier whose second optical input is coupled through additional semitransparent mirror with output of additional light source and optical output is coupled through three reflecting mirrors, additional semitransparent mirror, and second lens with resonator for its additional pumping.

EFFECT: enhanced power without increasing device mass.

1 cl, 1 dwg

FIELD: laser engineering; emission-line narrowing devices built around diffraction grating.

SUBSTANCE: emission-line narrowing device has diffraction grating, master working side of diffraction grating, chamber for accommodating at least mentioned diffraction grating, helium source for blasting mentioned chamber, beam expanding device that functions to expand mentioned laser beams, turning gear for guiding mentioned expanded beam to working side of diffraction grating to select desired wavelength range from mentioned expanded beam. Method for regulating laser frequency dispersion involves guiding of gaseous helium flow to working side of diffraction grating; in the process pressure of blast gas is reduced to cut down optical effects of hot gas layer.

EFFECT: minimized thermal distortions in narrow-line lasers generating high-power and high-repetition-rate beams.

15 cl, 12 dwg

FIELD: pulsed solid state lasers; high-power nanosecond radiation pulse generation.

SUBSTANCE: proposed system has two solid state lasers using electrooptically Q-switched cavity and parametric light oscillators. There are master lasers and amplifiers. Two active elements of master lasers having polished side surface are placed in single-lamp light. Two active elements of amplifiers are placed in other single-lamp light. Each amplifier is connected in double-pass ring circuit. The latter has first polarizer, polarization plane 90 deg. shifter, active element, second polarizer, first rotary mirror, telescope, dual-beam refraction plate, and second rotary mirror, all arranged in tandem.

EFFECT: enhanced stability of radiation pulse parameters and operating reliability, reduced mass and size.

1 cl, 1 dwg

FIELD: optoelectronics.

SUBSTANCE: proposed optoelectronic transmitter has laser and optoelectronic converter. Newly introduced in device are electrooptic modulator, three mirrors, and first and second correcting lenses. Optical output of laser is coupled with optical input of optoelectronic converter through electrooptic modulator affording radiation output from optoelectronic converter; it also has three mirrors and first correcting lens ensuring parallelism of radiation flux. Optical output of optoelectronic converter that functions to provide for shaping output radiation at frequency exceeding laser radiation frequency is coupled through second correcting lens with optical input of laser for pumping the latter.

EFFECT: enhanced radiation power raised without using large components.

1 cl, 1 dwg

FIELD: optical instrument engineering.

SUBSTANCE: before conversing parallel laser radiation beam of continuous cross-section to circular-section beam, the central round-shaped part is cut out of parallel laser radiation beam for subsequent delivery to specified circular-section beam convergence point. Device has entrance and exit axions that are optically conjugated. One reflecting conic surface of axion is mounted onto ends of hollow rod connected with other reflecting conic surface of axions through pylons. Cavity of rod is divided by partition provided with nozzles for supplying coolant into mentioned compartments. Reflecting surfaces of axions and partition of rod are made with through axial holes. Diameter of axial hole of reflecting conic surface of axions is commensurable with diameter of spot of focused laser radiation. Laser radiation beams can be focused with higher power of density.

EFFECT: increased power density.

4 cl, 1 dwg

FIELD: producing active elements with internal mirrors for stabilized dual-frequency gas lasers.

SUBSTANCE: optical assemblies are placed prior to and after annealing in magnetic field whose cross component is perpendicular to active element axis amounting to 0 < H ≤ 50 mT. Direction of magnetic-field induced cross component is determined and mark is applied. Assemblies are positioned until marks are aligned. Optical assemblies are soldered when marks are positioned on those corresponding to alignment between directions of cross components of magnetic field.

EFFECT: enhanced stability of laser radiation polarizing properties.

1 cl, 2 dwg

FIELD: laser engineering; destruction and directive change of mountain rock properties.

SUBSTANCE: proposed method includes formation of radiation density distribution over desired generation spectrum by pumping active medium with aid of laser. On one end pressure and acoustic radiation frequency are shaped within desired variation range of magnitude and direction. On other end directive magnetic field is acted upon synchronously with reflecting resonators. The latter periodically convey reflected beam to pumping chambers for enhancing energy density and power of laser beam; Geotechnological laser has pumping device, resonators, dispersion device, and magneto-acoustic space-time modulators. Dispersion devices are made in the form of rotary sound converter units with radiators. Radiation beam amplifying concentrators are coupled with pumping chambers; generation unit is provided with additional pumping chambers. Pumping chambers are mounted in two modules filled with active media. The latter are arranged in direction of optical axes perpendicular to direction of radiation beam linear dispersion. Laser heads of each module are relatively offset in vertical plane. Shielding reflectors are coupled with radiation beam amplifying concentrators.

EFFECT: ability of forming desired energy density, power, and beam intensity for destruction, synthesis, and directed change of mountain rock properties.

2 cl, 4 dwg

FIELD: laser engineering.

SUBSTANCE: proposed solid-state pulsed laser system designed for operation in subnanosecond and nanosecond frequency bands incorporating provision for converting radiation frequency into higher harmonics in visible and ultraviolet spectrum ranges has microchip laser with passive gate of YAG:Cr4+ crystal, two-port amplifier, and nonlinear components for converting radiation frequency into higher harmonics. In addition, it is provided with preamplifier. Introduced into preamplifier optical system on one end of active element are first nontransmitting mirror, input polarizer, electrooptic element, 90-deg. polarization-plane shifter installed on first two-position shifting device, prism, output polarizer, turning mirror, second nontransmitting mirror covered with first section of double-section screen, and third nontransmitting mirror. Electrooptic element is introduced in optical system of two-port amplifier.

EFFECT: ability of generating unidirectional digitally frequency-tuned pulses with smoothly varying power.

1 cl, 1 dwg, 1 tbl

FIELD: laser engineering.

SUBSTANCE: proposed solid-state pulsed laser system designed for operation in subnanosecond and nanosecond frequency bands incorporating provision for converting radiation frequency into higher harmonics in visible and ultraviolet spectrum ranges has microchip laser with passive gate of YAG:Cr4+ crystal, two-port amplifier, and nonlinear components for converting radiation frequency into higher harmonics. In addition, it is provided with preamplifier. Introduced into preamplifier optical system on one end of active element are first nontransmitting mirror, input polarizer, electrooptic element, 90-deg. polarization-plane shifter installed on first two-position shifting device, prism, output polarizer, turning mirror, second nontransmitting mirror covered with first section of double-section screen, and third nontransmitting mirror. Electrooptic element is introduced in optical system of two-port amplifier.

EFFECT: ability of generating unidirectional digitally frequency-tuned pulses with smoothly varying power.

1 cl, 1 dwg, 1 tbl

Up!