WO2021017539A1 - 激光辐射三倍率产生的装置 - Google Patents

激光辐射三倍率产生的装置 Download PDF

Info

Publication number
WO2021017539A1
WO2021017539A1 PCT/CN2020/085824 CN2020085824W WO2021017539A1 WO 2021017539 A1 WO2021017539 A1 WO 2021017539A1 CN 2020085824 W CN2020085824 W CN 2020085824W WO 2021017539 A1 WO2021017539 A1 WO 2021017539A1
Authority
WO
WIPO (PCT)
Prior art keywords
frequency
triple
fundamental wave
crystal
double frequency
Prior art date
Application number
PCT/CN2020/085824
Other languages
English (en)
French (fr)
Inventor
周建平
Original Assignee
南京钻石激光科技有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 南京钻石激光科技有限公司 filed Critical 南京钻石激光科技有限公司
Publication of WO2021017539A1 publication Critical patent/WO2021017539A1/zh

Links

Images

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/35—Non-linear optics
    • G02F1/3501—Constructional details or arrangements of non-linear optical devices, e.g. shape of non-linear crystals
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/35—Non-linear optics
    • G02F1/353—Frequency conversion, i.e. wherein a light beam is generated with frequency components different from those of the incident light beams
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/35—Non-linear optics
    • G02F1/355—Non-linear optics characterised by the materials used
    • G02F1/3551—Crystals
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/35—Non-linear optics
    • G02F1/3501—Constructional details or arrangements of non-linear optical devices, e.g. shape of non-linear crystals
    • G02F1/3509—Shape, e.g. shape of end face
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/35—Non-linear optics
    • G02F1/353—Frequency conversion, i.e. wherein a light beam is generated with frequency components different from those of the incident light beams
    • G02F1/354—Third or higher harmonic generation

Definitions

  • the present invention relates to the field of laser technology, in particular to a device for generating a triple rate of laser radiation. Especially the device and principle of ultraviolet laser radiation generated by the third or fourth harmonic outside the laser beam cavity.
  • the existing known gain media can provide the required laser radiation of various colors at various power levels and operating modes through gas, solid-state materials, electrically pumped semiconductors, and optical pumping.
  • Semiconductors are used as gain media to generate ultraviolet, visible and infrared laser radiation.
  • Gas lasers can produce good ultraviolet (uv), visible light and infrared (ir) light.
  • Electronically or optically pumped semiconductor lasers can generate infrared and near-infrared basic laser sources and their harmonics in the visible frequency range.
  • Direct semiconductor laser radiation can produce red and blue light, and ultraviolet radiation has good electrical conversion efficiency.
  • semiconductor diode lasers cannot be used to directly generate ultraviolet laser beams with high pulse intensity and high beam quality, but are used in various microelectronic semiconductor industrial applications such as circuit board processing or wafer cutting.
  • the design of nanosecond pulsed lasers based on intracavity or out-of-cavity triple frequency has partially solved the needs of industrial processing for nanosecond pulsed lasers.
  • ultrafast pulse lasers are generally not suitable for intracavity tripling schemes. Almost all high-energy picosecond or femtosecond ultrafast pulse ultraviolet conversions are performed outside the cavity.
  • the frequency doubled and tripled crystals generated by the second and third harmonics can be directly used for frequency conversion of the beam output by the infrared laser to generate an ultraviolet beam.
  • the cross-sectional light intensity distribution of the laser beam required for precision processing must meet certain requirements.
  • the ultraviolet output beam generated by the external frequency doubling device requires adjustment of the cross-sectional shape of the spot.
  • the non-linear crystal and the optical components that adjust the ultraviolet beam will be damaged. Therefore, the optical components that generate and adjust the ultraviolet laser beam have a limited service life, and it is difficult to meet the required long-term operation requirements.
  • One solution is to move the triple frequency crystal or other optical components so that the damaged crystal or optical component can be reused in a new undamaged spot position. Even so, generally speaking, the geometric size of the crystal or ultraviolet optical components is limited, and the service life of the entire device is limited.
  • the triple frequency crystal that needs to be coated with three different wavelength antireflection coatings.
  • the beam cross section at the exit interface when the ultraviolet beam exits becomes larger, the light density becomes lower, and the life of the triple frequency crystal is prolonged. Since the fundamental wave in the cavity is incident in front of the Brewster angle crystal of the frequency doubling crystal, the fundamental beam has a roundness determined by the cavity. After the frequency doubling crystal goes back and forth, the generated ultraviolet beam can maintain the basic shape of the fundamental wave. Therefore, this patent is more suitable for intracavity triple frequency.
  • this product does not use pre-adjustment of the fundamental wave and second harmonic beam cross-sectional intensity distribution that generates the third harmonic, but uses additional ultraviolet optical components to adjust the generated ultraviolet spot. .
  • the design of this product is complex and costly. It does not cleverly solve the problem of beam cross-section deformation, but uses multiple ultraviolet optical elements to correct the beam cross-section shape after conversion, thereby increasing the product.
  • the purpose of the present invention is to solve at least one of the technical defects.
  • the purpose of the present invention is to provide a device for generating extra-laser frequency tripling to overcome the complexity or high cost of the existing laser extra-cavity tripping device.
  • This method is also suitable for quadrupling. Frequency generation.
  • the embodiments of the present invention provide a variety of laser radiation triple-rate generation devices, including: a front optical system and a triple-frequency crystal, wherein,
  • An incident surface of a certain optical component in the front optical system is cut into a Brewster incident angle interface, which is used to adjust the light intensity distribution of the input fundamental wave beam and convert the incident fundamental wave beam into a fundamental wave beam.
  • Wave and double frequency harmonics so that the cross-sectional light intensity distribution shape of the converted fundamental wave and double frequency harmonics is adjusted, and the adjusted fundamental wave and double frequency harmonic beams are emitted to the third Frequency doubling crystal
  • the exit surface of the triple frequency crystal is cut into a Brewster exit angle interface, and the input fundamental wave and double frequency harmonics are sum-frequency converted in the triple frequency crystal to generate a triple frequency harmonic beam ,
  • the triple-frequency harmonic beam exits after passing through the Brewster exit angle interface, and is corrected to be required, or is basically consistent with the cross-sectional light intensity distribution shape of the initial input fundamental wave beam, or is required ,
  • the beam of the triple frequency beam is emitted.
  • the cross-sectional light intensity distribution shape of the incident fundamental wave beam is a circle
  • the cross-sectional light intensity distribution shape of the remaining fundamental wave, the second harmonic and the third harmonic in the third frequency crystal It is elliptical
  • the shape of the triple frequency outgoing beam is circular.
  • the front optical system includes at least one double frequency crystal for converting the input fundamental wave beam into double frequency harmonics and remaining fundamental waves, so that the generated remaining fundamental wave and double frequency harmonics are horizontal
  • the light intensity distribution shape of the cross section is adjusted.
  • the front optical system includes: a compensation module, also called a compensation crystal, which receives the fundamental wave and double frequency harmonics, and realizes a spatial walk-off angle or The pulse delays in time are staggered, or both, adjustment or pre-compensation is made to produce high-quality or high-conversion-efficiency third harmonics, so that the beam directions of the fundamental and second harmonics Collinear or better synchronization inside the triple frequency crystal of secondary frequency conversion
  • exit interface of the double frequency crystal adopts a coating that fully transmits the fundamental wave and the double frequency harmonic
  • the incident interface of the triple frequency crystal adopts an antireflection coating for the incident direction of the fundamental wave and the double frequency wave.
  • the fundamental wave and the double frequency harmonic pass through the compensation module to realize the spatial walk-off angle adjustment, so that the beam directions of the fundamental wave and the double frequency harmonic are more collinear.
  • the compensation module adopts one of the following forms:
  • the front optical system includes: a transition medium, a double frequency crystal and a compensation module, wherein:
  • the incident surface of the transition medium is cut into the Brewster incident angle interface, which is used to adjust the light intensity distribution of the input fundamental wave beam, so as to adjust the cross-sectional shape of the fundamental wave generated, and exit to the double frequency Crystal
  • the double frequency crystal converts the fundamental wave emitted by the transition medium into double frequency harmonics, and emits the remaining fundamental and double frequency harmonics to the compensation module;
  • the compensation module receives the incidence of the fundamental wave and the double frequency harmonic, and adjusts the spatial walk-off angle of the fundamental wave and the double frequency harmonic to make the fundamental wave and the double frequency harmonic
  • the light beams of the waves overlap better in space when generating the triple frequency conversion.
  • the double frequency crystal staggers the pulse delay in the generation time of the fundamental wave and the double frequency harmonic, and the compensation crystal realizes the relative delay adjustment in time for the fundamental wave and the double frequency harmonic. , So that the light beams of the fundamental wave and the double frequency harmonics overlap better in time when generating the triple frequency conversion.
  • the front optical system includes: a double frequency crystal, a transition medium and a compensation module, wherein:
  • the double frequency crystal converts the incident fundamental wave beam into a fundamental wave and double frequency harmonics, and emits the fundamental wave and double frequency harmonics to the transition medium;
  • the incident surface of the transition medium is cut into the Brewster incident angle interface, which is used to adjust the light intensity distribution of the input fundamental wave and the second harmonic generated by the fundamental wave, so as to adjust the fundamental wave and the second harmonic generated by the fundamental wave.
  • the cross-sectional shape of the wave is adjusted and emitted to the compensation module;
  • the compensation module receives the incidence of the fundamental wave and the double frequency harmonics, and adjusts the space departure angle or the temporal pulse delay stagger of the fundamental wave and the double frequency harmonics.
  • the front optical system includes part or all of: a frequency triple crystal, a frequency double crystal, and an optical reflective component, and one interface of the frequency triple crystal is cut into a Brewster angle interface, which also serves as the base Wave beam incident surface, where
  • the fundamental wave beam is incident on the Brewster angle interface of the frequency-doubling crystal, and the light intensity distribution of the input fundamental wave beam is adjusted, and then it is emitted to the frequency-doubling crystal;
  • the double frequency crystal converts the fundamental wave adjusted by the triple frequency crystal into double frequency harmonics, and emits the remaining fundamental and double frequency harmonics to the optical reflecting component;
  • the optical reflection component After the optical reflection component reflects and turns the fundamental wave and the double frequency harmonic, it enters the double frequency crystal again, and the double frequency crystal passes through again to remove the remaining fundamental wave and double frequency harmonic Emitted to the triple frequency crystal;
  • the input fundamental wave and double frequency harmonics are sum-frequency converted by the triple frequency crystal in the triple frequency crystal to generate triple frequency harmonics, and the triple frequency harmonics pass through the After the Brewster angle interface of the triple frequency crystal is emitted, it is corrected to be basically the same as the shape of the cross-sectional light intensity distribution of the initial input fundamental wave beam, or the desired triple frequency exit beam.
  • optical reflection component adopts one of the following forms:
  • the front optical system further includes: a compensation crystal, and the compensation module is located between the three-frequency crystal and the two-frequency crystal, and is used for realizing spatial analysis of the fundamental wave and the second-frequency harmonic.
  • the departure angle and time delay of the pulse are staggered and adjusted.
  • the relative position of the light outputting the triple frequency harmonic at the exit point of the triple frequency crystal is adjusted. To the effect of changing points.
  • the relative position of the light outputting the harmonics of the triple frequency at the exit point of the frequency triple crystal is adjusted to play the role of changing points.
  • the relative position of the exit point of the light outputting the triple frequency harmonics on the Brewster corner surface of the triple frequency crystal is adjusted. , Does not cause any change or movement of the output beam, and plays the role of changing points.
  • the relative position of the exit point of the light outputting the triple frequency harmonics on the Brewster angle surface of the triple frequency crystal is adjusted to play the role of point change.
  • the crystal in the front optical system and the frequency-tripping crystal adopt one of the following forms: LBO, LiNOb, LiTb, BBO, LKP, KD*P, ⁇ -BBO, quartz crystal, PPLN, PPTN, PPKT Or other crystals.
  • the triple frequency crystal uses phase matching to generate the double frequency of the double frequency wave
  • the incident double frequency harmonics are converted into the quadruple frequency harmonics, passing through the Brewster angle of the triple frequency crystal
  • the output from the interface is corrected to a quadruple-frequency output beam that is basically consistent with the shape of the cross-sectional light intensity distribution of the initial input fundamental wave beam, or required.
  • the beam quality of the secondary laser frequency conversion outside the cavity can be improved, the need for shaping the shape of the ultraviolet beam is eliminated, the cost is reduced, the life of the triple frequency crystal is prolonged, and the laser generation
  • the third-harmonic nonlinear crystal does not need to be coated on the output surface to achieve nonlinear frequency conversion.
  • the present invention generates triple frequency or other multiple frequency multiples, usually, but not limited to, a triple frequency 355nm ultraviolet laser with a wavelength of 1064nm, or a fourth harmonic generation of 266nm, or other sub-harmonics, deep ultraviolet Light, using simple and reliable multiple frequency double conversion to produce ultraviolet or deep ultraviolet laser beams, to meet the needs of long-life, high-stability and low-cost ultraviolet lasers.
  • a compensation module is added to pre-compensate for the deviation angle or time delay between the second harmonic and the fundamental wave due to the harmonic conversion process Staggering can significantly improve the efficiency of the second frequency conversion to generate the third harmonic (3 ⁇ ) or fourth harmonic (4 ⁇ ) beam;
  • Fig. 1 is a structural diagram of a device for generating a triple rate of laser radiation according to an embodiment of the present invention
  • FIG. 2 is a structural diagram of a device for generating a triple rate of laser radiation using a double frequency crystal and a compensation module according to an embodiment of the present invention
  • Fig. 3 is a structural diagram of a device for generating a triple rate of laser radiation using an optical reflective component according to an embodiment of the present invention
  • Fig. 4 is a structural diagram of a device for generating a triple rate of laser radiation using a transition medium, a double frequency crystal and a compensation crystal according to an embodiment of the present invention.
  • the invention provides a device for generating a triple rate of laser radiation, which is suitable for outside and inside a cavity and can generate a triple frequency laser of an ultraviolet laser beam.
  • the present invention uses a Brewster angle output interface medium frequency conversion device, combined with frequency doubling crystals or other media, to pre-adjust the light intensity shape of the transverse interface of the input beam and the harmonic beam generated in the middle, and may include adjusting the interaction of each
  • the walk-away angle between the beams may include adjusting the time delay, and then perform the UV frequency conversion, passing through a Brewster angle exit surface, so that the cross-sectional intensity distribution of the generated UV output beam can be adjusted and a better conversion efficiency can be achieved .
  • the device for generating laser radiation at a triple rate includes: a front optical system and a triple frequency crystal.
  • the front optical system 1020 is used to adjust the light intensity distribution of the input fundamental wave beam, and convert the fundamental wave beam into fundamental wave and double frequency harmonics, so that the generated fundamental wave and double frequency harmonics are The light intensity distribution shape of the cross-section is adjusted, and the adjusted fundamental wave and double frequency harmonics are emitted to the triple frequency crystal.
  • the front optical system 1020 can use a transparent incident medium, and the incident interface is equal to or approximately equal to the brewster angle of the transparent medium. The angle of incidence is cut as a preferable value.
  • the exit surface of the triple frequency crystal 30 is cut into the Brewster exit angle interface, and the input fundamental wave and double frequency harmonics are sum-frequency converted in the triple frequency crystal to generate triple frequency harmonics and triple frequency harmonics After exiting through the Brewster exit angle interface, it is corrected to be basically the same as the shape of the cross-sectional light intensity distribution of the initial input fundamental wave beam, or as needed, the triple frequency exit beam.
  • the phase matching of the frequency triple crystal 30 is cut in the direction of the angle where the third harmonic is generated, and the interface with at least the third harmonic emitted is the Brewster angle arrangement of the emitted light beam.
  • an appropriate front optical system 1020 is selected to realize the cross-sectional shape of the fundamental wave beam and converted into a double-frequency harmonic beam, so that the input fundamental wave beam 11 passes through the front optical system 1020 to produce a double
  • the final required triple or quadruple harmonic 31 is generated efficiently, and finally leaves the transition device at the approximate Brewster angle exit interface After 400, the triple frequency or quadruple frequency beam 32 exits the interface 400 in the P-polarization state, and the light intensity distribution of its cross section is optimized.
  • the interface 400 does not need to be coated with an antireflection coating, and the loss of the P-polarized triple or quadruple frequency beam is small, and the light intensity decreases after the area of the beam on the interface increases , So that the life of the interface irradiated by the ultraviolet beam is prolonged.
  • the cross-sectional light intensity distribution shape of the fundamental wave beam is circular, and the transverse direction of the fundamental wave, the second harmonic and the third harmonic in the third frequency crystal
  • the cross-sectional light intensity distribution shape is an ellipse, and the shape of the triple-frequency outgoing beam is a circle. That is, the cross-sectional light intensity distribution shape of the fundamental wave beam 11 is a circle, which is a circularly symmetric beam. After passing through the arrangement of the Brewster angle of the front optical system 1020, the shape of the fundamental wave 11 is adjusted so that the remaining fundamental wave 12 is generated.
  • the shape of the and double frequency beam 23 is elliptical, and the remaining fundamental wave 12 and the double frequency beam 23 are then incident on the frequency triple crystal 30, where the interface 300 of the frequency triple crystal 30 is opposite to the remaining fundamental wave 12 and double frequency beam
  • the shape of 23 is not changed, the fundamental wave 12 and the double frequency beam 23 are converted to generate a triple frequency beam 31,
  • the cross-sectional shape of the generated frequency tripled beam 31 and the beam 12 are close. After exiting from the Brewster angle of the interface 400 of the frequency tripled crystal 30, the resulting ultraviolet beam 32 is corrected to the desired circular shape, and the beam 32 can be basically maintained The shape of the fundamental beam 11. After exiting from the exit interface 400, the light intensity distribution of the beam 32 reaches the desired cross-sectional light intensity distribution shape.
  • the device required in this embodiment adjusts the intensity distribution of the incident fundamental wave beam cross-section or the fundamental wave and the generated double-frequency harmonic beam intensity distribution in advance.
  • the required method is relative to the adjustment of the final output.
  • the UV beam is much simpler, practical and low-cost. Since the final output ultraviolet beam does not need to be adjusted by optical components, the possibility of damage to the components by the ultraviolet beam is reduced, which makes the service life of the entire system longer.
  • the present invention includes at least one device (triple frequency crystal 30) that is approximately the Brewster angle exit interface. After the UV beam is emitted, the cross-sectional light intensity distribution of the harmonic output beam that needs to be generated can reach the desired ideal light intensity distribution .
  • the spatial deviation angle of the fundamental wave and the double frequency harmonic or the time difference of the fundamental wave and the double frequency harmonic may be included or not. Misalignment, full or partial compensation or adjustment.
  • the entrance interface 100 of the front optical system 1020 and the exit interface 400 of the frequency triplet crystal are both Brewster interfaces, and an antireflection coating is not necessarily required.
  • the frequency-doubling laser device of this embodiment that can be used outside or inside the cavity uses a transparent medium that is incident at Brewster's angle and adjusts the beam intensity distribution of the input fundamental wave cross-section, and a medium cut at Brewster's angle, so that the Brewster angle
  • the incident or outgoing fundamental wave and third harmonic after the beam outside the cavity passes through the nonlinear conversion crystal and exits the triple frequency crystal for the second time, it cancels all or part of the change in the beam diameter due to Brewster’s incident surface , Adjust or basically maintain the cross-sectional shape or intensity distribution of the original incident fundamental wave, so that the cross-sectional shape of the final frequency tripled beam is basically the same as the original incident fundamental wave shape, or achieve the desired beam shape.
  • the front optical system uses a double frequency crystal 20, and the incident surface of the double frequency crystal 20 is cut into a Brewster incident angle interface, so that the interface 100 does not need to be coated with an anti-reflection coating and will also be incident on the P-polarization. There is no loss when the fundamental wave is incident at Brewster's angle.
  • the double frequency crystal 20 is used to convert the input fundamental wave beam into double frequency harmonics and remaining fundamental waves, so that the cross-sectional light intensity distribution shapes of the remaining fundamental waves and double frequency harmonics generated are adjusted.
  • the fundamental wave and double frequency harmonics are emitted to the triple frequency crystal.
  • the incident angle interface 100 of the frequency-doubled crystal is equal to or approximately equal to the Brewster angle of the crystal. When the Brewster surface is used as the incident surface 100, no antireflection coating is required.
  • the exit interface 200 of the double frequency crystal 20 adopts a coating that fully transmits the fundamental wave and double frequency harmonics. If the fundamental wave and the double-frequency wave can be the same P-polarization, the interface 200 can also be used, but it is not necessary, and is designed to be the Brewster exit angle. It should be noted that if the polarization directions of the fundamental wave and the double frequency wave are different, an antireflection coating is generally required when using the direct incident.
  • the exit surface 400 of the triple frequency crystal 300 is cut into the Brewster exit angle interface, and the input fundamental wave and double frequency harmonics are sum-frequency converted in the triple frequency crystal to generate triple frequency harmonics and triple frequency harmonics.
  • the wave exits after passing through the Brewster exit angle interface, and is corrected to a triple frequency exit beam that is basically consistent with the initial input fundamental wave beam's cross-sectional light intensity distribution shape.
  • the incident interface of the triple frequency crystal adopts a coating that fully transmits the fundamental wave and the double frequency wave, and the antireflection coating is coated on the geometric form facing the incident.
  • the frequency triple crystal 30 is selected as the sum frequency of the fundamental wave and the double frequency beam (frequency addition: ( ⁇ +2 ⁇ )) phase matching, and the generated triple frequency (3 ⁇ ) beam is P when exiting from the interface 400 -Polarization, exit along Brewster's angle.
  • the phase matching of the frequency triplet crystal 30 is cut in the angular direction where the third harmonic is generated, and the interface with at least the third harmonic is the exit beam arranged at the Brewster angle.
  • the exit Brewster interface 400 does not necessarily need to be coated with an antireflection coating.
  • the laser frequency tripling laser device of the present invention is used outside the cavity to generate a related laser beam with a frequency triple (or a quadruple frequency) after the second frequency doubling.
  • the crystals cut along the two Brewster angles are in Brewster.
  • the angle of incidence and exit of the Brewster section at least twice, the effective frequency triple (or quadruple) laser beam is generated, and the outgoing beam caused by the single or odd number of passes through the crystal with the Brewster angle cut surface is subtly corrected
  • the cross-sectional symmetry is significantly changed compared to the original incident beam cross-sectional light intensity distribution.
  • the triple frequency (or quadruple frequency) beam is separated from the fundamental wave and the double frequency wave.
  • This method has full transmission for P-polarized triple frequency (or quadruple frequency) beams and does not require anti-reflection coating.
  • the input fundamental wave beam 11 is a circularly symmetric beam. After passing through such a device, it passes through the Brewster incident interface of the double frequency crystal 20, so that the beam 12 and the beam 23 are adjusted to an elliptical beam shape. In the further sum frequency generation process, the generated triple-frequency beam 31 is elliptical in the crystal 30. After the light beam 31 exits through the Brewster angle that is finally output by the interface 400, it becomes a circularly symmetric light intensity distribution with a circular cross-section of the light beam, rather than an obvious non-circular intensity distribution. Therefore, the subsequent optical system that needs to correct the roundness of the ultraviolet laser beam is omitted.
  • This embodiment first uses the Brewster angle-incident double frequency crystal 20 and the Brewster angle-cut triple frequency crystal 30 for the fundamental beam 11, so that the fundamental wave and third harmonic incident or emitted at the Brewster angle are After the external beam passes through the nonlinear conversion crystal for the second and third frequency and exits the frequency tripler crystal 30, it cancels all or part of the beam diameter change due to Brewster's incident surface, and adjusts or basically maintains the original fundamental wave cross section
  • the shape or intensity distribution makes the cross-sectional shape of the final frequency tripled beam basically the same or approximately the same as the original fundamental wave shape.
  • the present invention can also adjust the original beam cross-sectional shape, such as adjusting to an ellipse whose beam radius in the light incident surface of the exiting Brewster interface is significantly wider than its vertical direction.
  • the cross-sectional light intensity distribution makes the cross-sectional beam size of the finally generated ultraviolet output beam equal in the two orthogonal vertical directions described above, or meet the required spot shape.
  • the device of this embodiment is generally used outside the laser cavity to generate a triple or quadruple laser beam after double frequency doubling, along the last non-normal incident surface that produces harmonic output, usually Near Brewster angle exit surface 400.
  • Near Brewster angle exit surface 400 When exiting, because the p-polarized light emitted near Brewster angle has a larger spot on the exit end surface, the intensity of ultraviolet light on this surface becomes smaller, and this Brewster angle surface 400 faces p -Polarized light has the characteristic of being able to be fully transmitted without the need for antireflection coating, which makes the overall service life of the device longer and the manufacturing cost smaller.
  • the front optical system 1020 can also design a double frequency crystal or a separate crystal medium to adjust the relative departure angle of the generated fundamental wave and double frequency harmonics, so that they can be used for further testing when the sum frequency is generated. ,
  • the collinearity is improved, so that the conversion efficiency is improved.
  • a compensation medium can also be designed to compensate and adjust the time delay stagger between the fundamental wave and the double frequency harmonic, so that they can further produce the sum frequency mixing effect.
  • the time overlap is improved, the conversion efficiency is improved, the difficulty of further correction of the UV beam roundness and the need for high-priced UV optical correction components are omitted, and the adjustment UV that affects the life of the device is also reduced.
  • the optical element of the light beam thus prolongs the life of the entire laser frequency conversion device and reduces the cost of the device.
  • the front optical system may also include, but does not necessarily include, a compensation crystal 40.
  • the incident surface of the double frequency crystal 20 is cut into the Brewster incident angle interface 100, and the input fundamental wave beam is converted into the fundamental wave and double frequency harmonics, so that the cross sections of the fundamental wave 12 and the double frequency harmonic 22 generated
  • the light intensity distribution shape is adjusted; the compensation crystal 40 receives the incidence of the fundamental wave 12 and the double frequency harmonic 22, and compensates or precompensates the spatial walk-off angle of the fundamental wave 12 and the double frequency harmonic 22 to improve the three The light output efficiency of the doubled harmonic 32.
  • the adjustment of the distance between the fundamental wave 12 and the double frequency harmonic 22 in time is to use the difference in group velocity to adjust the distance between the fundamental wave 12 and the double frequency harmonic 22 in time, so that the fundamental wave 12 and The energy propagation of the double frequency harmonic 22 is optimized in time overlapping and is suitable for generating a high-efficiency pulsed ultraviolet beam.
  • a variety of special devices can be derived from the above method to achieve further adjustment of the ultraviolet light intensity distribution without using multiple ultraviolet light resistant optical elements.
  • the beams of the frequency doubling harmonics 22 are collinear in the propagation direction inside the frequency triple crystal to correct the beam direction.
  • the adjustment of the spatial walk-off angle can be achieved by adjusting the different refraction angles of the fundamental wave 12 and the double frequency harmonic 22 by the compensation crystal 40, so that the energy propagation of the fundamental wave 12 and the double frequency harmonic 22 are optimized in space. It is suitable for generating high-efficiency and high-quality UV beams with beam intensity distribution.
  • the compensation module 40 may adopt a birefringent crystal that is transparent to the fundamental wave and the second harmonic.
  • a birefringent crystal that is transparent to the fundamental wave and the second harmonic.
  • LBO, LiNOb, LiTb, KD*P, ⁇ -BBO, LKP, KD*P, ⁇ -BBO, quartz crystal, etc. which are oriented at certain angles.
  • the compensation module 40 takes one of the following forms:
  • the fundamental wave beam 11 has a conventional circularly symmetrical cross-sectional light intensity distribution.
  • the fundamental beam 11 is incident on the Brewster angle interface 100 of the double frequency crystal 20, the cross section changes from a circle to an ellipse, and enters the double frequency crystal crystal 20 after refraction.
  • the crystal 20 passes through, the phase matching is obtained. It is effectively converted into a double frequency laser beam 22 for the first time, and exits the crystal 20 from the interface 200.
  • the cross-sectional size of the beam 11 becomes the fundamental beam 12 because it is incident at the Brewster angle.
  • the beam diameter in one direction of the fundamental beam 12 is larger than the incident surface formed by the original beam 11 on the incident light and the normal of the end face 100 The diameter inside becomes larger.
  • the light beam 11 passes through the crystal 20, it becomes the fundamental wave 12 and the double frequency harmonic 22 and enters the compensation crystal 40.
  • the departure angle of the two beams of the fundamental wave 12 and the double frequency harmonic 22 is or The shift in time is staggered.
  • the angle or temperature or other characteristics of the designed crystal 40 are adjusted to obtain the required space or time or both, so that they enter the triple frequency crystal after passing through the interface 300
  • the third frequency is converted into the third frequency inside the crystal 30, it is more overlapped in space or more synchronized in time or both.
  • the second frequency is converted into the third harmonic in the crystal 30 more effectively, and the third frequency is generated.
  • the cross-sectional shape of the beam is corrected from an ellipse to a circle, and becomes a harmonic beam 32 with a triple frequency.
  • the cross-section of the third harmonic beam 32 has a beam diameter on the paper. It is refracted by the Brewster interface and then reduced, and the angle generated by the dispersion is different from the remaining fundamental beam 16 and the remaining double frequency beam 25.
  • Angle separation after leaving the interface 400, after a certain distance propagation, it can be further effectively separated, and the beam cross section can be restored to the original shape when the fundamental wave was incident or maintain the required truth degree, and also make the third harmonic beam generated 32 is easily separated from the device.
  • the Brewster angles of the interface 100 and the interface 400 are basically the same. Therefore, the light beam 11 can be converted into the triple-frequency harmonic light beam 32 with the original cross section without complicated correction.
  • the materials of the crystal 20 and the crystal 30, and the Brewster angles of the crystal interface 100 and the interface 400 are basically the same, so that the fundamental beam 11 and the triple harmonic 32 have basically the same shape, which meets the needs of subsequent applications.
  • the above-mentioned embodiment provided by the present invention uses the double frequency crystal 20 incident at Brewster angle or other transparent medium that adjusts the beam intensity distribution of the input fundamental wave cross section, and the frequency triple crystal 30 cut at Brewster angle, so that the Brewster angle
  • the fundamental and third harmonics incident or exiting at an angle, the triple frequency beam generated after the beam passes through the nonlinear conversion crystal for the second time is refracted from the triple frequency crystal 30, and cancels all or part of the incident surface caused by Brewster.
  • the change of beam diameter adjusts or basically maintains the cross-sectional shape or intensity distribution of the original fundamental wave, so that the cross-sectional shape of the final frequency tripled beam is basically the same or approximately the same as the original fundamental wave shape.
  • a compensation crystal 40 that can adjust the departure angle or time stagger of the fundamental wave and the second harmonic between the two beam frequency conversion processes.
  • the double frequency crystal 20, the triple frequency crystal 30 and the compensation crystal 40 can be selected, such as LBO, BBO, ⁇ -BBO, quartz crystal, LiNOb, KTP, PPLN, PPKTP, PPTN, etc.
  • Non-linear laser crystals or their combination are cut in different directions to achieve the required angle for phase matching or space or time compensation.
  • the compensation module can be a compensation crystal or other optical components.
  • Figure 3 depicts a design similar to Figure 2, the main difference is that the design of Figure 2 is reversed and passed through the interface cut by Brewster's angle for the second time, so that the original incident beam 11 has a cross-sectional beam shape, and the exit three
  • the frequency-doubled laser beam 32 basically maintains the same or similar shape before outputting.
  • the output beam does not need to be corrected by additional beam cross-sectional beam intensity due to the change in the roundness of the beam cross-section when the beam exits the Brewster angle interface in a single shot during the second frequency doubling.
  • the Brewster angle component that is passed here for the first time can also be a separate optical component with pre-adjusted beam cross-sectional light intensity distribution, separate from the sum frequency crystal generated by the third harmonic.
  • the front optical system includes: a frequency triple crystal 30, a frequency double crystal 20, and an optical reflection component 02.
  • One interface of the frequency triple crystal 30 is cut into a Brewster angle interface 400, which also has a fundamental beam. The entrance surface and the exit surface of the fundamental wave and second harmonic.
  • the fundamental wave beam is incident on the Brewster angle interface 400 of the frequency-doubling crystal 30, and the light intensity distribution of the input fundamental wave beam 111 is adjusted to adjust the cross-sectional shape of the fundamental wave generated, and it is emitted to the frequency-doubling crystal 20.
  • the double frequency crystal 20 converts the fundamental wave sent by the triple frequency crystal 30 into double frequency harmonics, and emits the remaining fundamental wave and double frequency harmonics to the optical reflective part.
  • the optical reflection component 02 reflects the fundamental wave and the double frequency harmonic, it enters the double frequency crystal again, and the double frequency crystal performs the double frequency conversion when the fundamental wave passes through the second time to generate the double frequency harmonic.
  • the remaining fundamental wave and the second harmonic wave are emitted to the other interface 300 of the triple frequency crystal 30.
  • the input fundamental wave and double frequency harmonics are sum-frequency converted by the triple frequency crystal 30 in the triple frequency crystal 30 to generate triple frequency harmonics, and the triple frequency harmonics pass through Brewster of the triple frequency crystal 30 After the corner interface 400 is emitted, it is corrected to a triple-frequency outgoing beam 32 that is basically consistent with the cross-sectional light intensity distribution shape of the initially input fundamental wave beam.
  • the optical reflective component 02 takes one of the following forms:
  • the front optical system can also, but not necessarily, include: a compensation module, or called a compensation crystal, 40.
  • the compensation crystal 40 is located between the three-frequency crystal 30 and the two-frequency crystal 20, and is used to compare the fundamental wave And the double frequency harmonic realizes the deviation of the space departure angle and the time pulse delay departure to compensate.
  • Compensation module which receives the fundamental wave and double frequency harmonics, and realizes the separation angle of the fundamental wave and the double frequency harmonics in space or the pulse delay in time. It is conducive to the adjustment or pre-compensation of the third harmonic with high quality or high conversion efficiency, so that the beam directions of the fundamental wave and the second harmonic are collinear or synchronized within the third harmonic of the second frequency conversion. better.
  • the working principle of this embodiment is as follows: the fundamental wave 111 of the incident beam, assuming a beam intensity distribution with a circular cross-interface shape, enters the Brewster angle interface 400 of the frequency triple crystal 30, and enters at the Brewster angle. After the crystal 30, the beam intensity distribution becomes an elliptical cross-sectional shape in the crystal 30. After passing through the normal incident interface 300 of the crystal 30, the emitted beam 112 is still elliptical, and then passes through the crystal 40 and enters the double frequency crystal 20. Generate a double frequency beam 21. The cross-sectional shape of the double frequency beam 21 is an ellipse.
  • the optical reflection part 02 makes the fundamental wave (frequency ⁇ ) beam 112 and the double frequency (frequency 2 ⁇ ) beam 21 after 180 degrees or approximately 180 degrees of reflection and turning, enter the double frequency crystal 20 and the compensation crystal 40 again, and enter Into the interface 300 of the frequency triple crystal 30.
  • the double frequency crystal 20 produces a double frequency (2 ⁇ ) conversion when the fundamental wave 112 passes twice.
  • Fundamental wave 112 and second harmonic 22 continue to be elliptical cross-section beam 15 and elliptical cross-section second harmonic beam 24 in the case of phase matching of crystal 30, the second harmonic frequency ( ⁇ +2 ⁇ ) occurs
  • Frequency conversion produces a triple frequency (3 ⁇ ) beam 31 with an elliptical cross section.
  • the elliptical light beam 31 After the elliptical light beam 31 passes through the Brewster angle interface 400, it exits at the Brewster angle. After the cross section of the light beam 31 exits the interface 400, the diameter of the beam in the Brewster incident surface is adjusted to have or close to the original The original beam roundness of the fundamental wave is the triple frequency beam 32.
  • the initial fundamental wave 111 is a beam with a circular cross-section.
  • the generated triple-frequency beam 32 will leave with a basic circular cross-sectional beam shape.
  • the triple frequency beam 32 output by this device can basically maintain the original incident fundamental beam cross-sectional shape, except for some changes in the cross-sectional beam shape due to the phase matching of the nonlinear conversion during the frequency doubling process.
  • the generated triple-frequency output beam 32 can achieve the roundness required by the design without the need to adjust the beam cross-sectional shape.
  • the design of this scheme is ingenious and simple, and the manufacturing cost is low. Since no additional optical components are needed to further adjust the cross-section of the triple frequency beam, the structure is simple and the stability is high. Due to the use of the Brewster angle incident crystal, the cross-section of the fundamental, double and triple frequency beams inside and on the crystal becomes larger, and the life of the triple frequency crystal becomes longer. The service life of the entire device is extended.
  • the front optical system includes: a transition medium 10, a double frequency crystal 20 and a compensation crystal 40.
  • the transition medium 10 presets the input fundamental wave cross-sectional shape, as long as it is a transparent medium.
  • the incident surface of the transition medium 10 is cut into the Brewster incident angle interface, which is used to adjust the light intensity distribution of the input fundamental wave beam and exit to the double frequency crystal 20; the double frequency crystal 20 will be the fundamental wave emitted by the transition medium 10 Converted into double frequency harmonics, and emit the remaining fundamental and double frequency harmonics to the compensation crystal 40; the compensation module 40 receives the incident of the fundamental and double frequency harmonics, and realizes the fundamental and double frequency harmonics
  • the departure angle in space or the pulse delay departure and stagger in time are preset and compensated.
  • the compensation module 40 compensates the fundamental wave and the double frequency harmonics for the spatial walk-off angle or the pulse delay walk-off stagger, so that the beams of the fundamental wave and the double frequency harmonics overlap better in space or time. .
  • the transition medium has at least one interface cut with Brewster's angle to adjust the beam spot shape of the incident beam cross-section, so that the adjusted fundamental wave beam has the shape of the final spot that is conducive to generating the required output beam and is required for sum frequency conversion , The second harmonic beam and the remaining fundamental beam.
  • the sequence of the positions of the double frequency crystal 20 and the transition medium 10 can be exchanged. That is, the front optical system includes: a double frequency crystal 20, a transition medium 10, and a compensation crystal 40. That is, the incident surface of the transition medium 10 is cut into the Brewster incident angle interface, which is used to adjust the light intensity distribution of the input fundamental wave and the second harmonic wave, and exit to the compensation crystal 40; the compensation crystal 40 receives the fundamental wave and the second harmonic. The incidence of double-frequency harmonics compensates for the deviation of the fundamental wave and the double-frequency harmonics in space or time pulse delay.
  • the front optical system of the present invention includes: a triple frequency crystal, a double frequency crystal, and an optical reflection component.
  • One interface of the triple frequency crystal is cut into a Brewster angle interface, which also serves as the first incident surface of the fundamental beam .
  • the fundamental wave beam is incident on the Brewster angle interface of the frequency-doubling crystal, the cross-sectional light intensity distribution of the input fundamental wave beam is adjusted, and it is emitted to the frequency-doubling crystal.
  • the double frequency crystal converts the fundamental wave adjusted by the triple frequency crystal into a double frequency harmonic, and emits the remaining fundamental and double frequency harmonics to the optical reflective part.
  • the optical reflection component reflects the fundamental wave and the double frequency harmonics, and then enters the double frequency crystal again.
  • the double frequency conversion is performed to generate the double frequency harmonics, and the remaining fundamental wave and The double frequency harmonics are emitted to the triple frequency crystal.
  • the input fundamental wave and double frequency harmonics are sum-frequency converted in the triple frequency crystal by the triple frequency crystal to produce triple frequency harmonics.
  • the output is corrected to a triple-frequency output beam that is basically the same as the shape of the cross-sectional light intensity distribution of the initial input fundamental wave beam or the desired shape.
  • this embodiment uses an optically transparent transition medium 10 with a refractive index similar to or the same as that of the medium 30, and an interface of the medium is made as a Brewster angle incident surface, so that the cross section of the incident beam is
  • the third harmonic generated through the triple frequency crystal 30 exits, the cross-sectional light intensity distribution shape of the output beam of the triple frequency crystal basically maintains the cross-sectional light intensity distribution shape of the input beam feature.
  • the incident wave cross-section light intensity distribution shape is a circularly symmetrical fundamental wave beam 11
  • the fundamental wave beam 11 cross-sectional intensity distribution shape becomes Beam 12 of elliptical cross section.
  • the light beam 12 enters the double frequency crystal 20, and when the light beam 12 passes through the double frequency crystal 20 for harmonic conversion, a second harmonic (double frequency) light beam 22 similar to the cross-sectional shape of the light beam 12 is generated.
  • the deviation angle or time delay between each other causes the light beam 23 to enter the second conversion to generate the triple frequency (
  • the sum-frequency) crystal 30 generates a more effective sum-frequency beam 31.
  • the shape of the cross-sectional light intensity distribution of the generated triple-frequency beam 31 is also an elliptical shape, and roughly has the elliptical shape of the fundamental wave 12 adjusted by the interface 100.
  • the light beam 31 with an elliptical cross-section passes through the interface 400.
  • the light beam 31 can be emitted at the interface 400 at the Brewster angle after passing through the Brewster angle interface.
  • the cross-section of is adjusted by the interface 400 to a triple frequency beam 32.
  • the cross-sectional light intensity distribution of the triple frequency beam 32 can be basically consistent with the roundness characteristics of the original incident beam 11.
  • the present invention can obtain the required cross-sectional light intensity distribution of the triple frequency output beam by adjusting the symmetry of the cross-sectional light intensity distribution of the input fundamental wave.
  • the use of the invention can avoid the need to adjust the beam shape of the beam with the triple frequency, usually ultraviolet wavelength, the complicated optical device that needs to adjust the beam shape, and the difficulty of overcoming the short life of such optical device after being irradiated by ultraviolet light.
  • the obtained triple-frequency ultraviolet light output device does not need to be coated with an anti-reflection coating for the third harmonic on the output surface, and has the advantages of simple device, low cost, stable performance, long life and the like.
  • the light spot for outputting the third harmonics is adjusted by moving the double frequency crystal in parallel or adjusting the beam intensity distribution of the input fundamental wave cross section.
  • the position of the exit point of the triple frequency crystal plays a role of changing points.
  • the relative position of the light outputting the triple frequency harmonics at the exit point of the triple frequency crystal is adjusted to play the role of point change.
  • the position of the exit point of the light outputting the triple frequency harmonics on the Brewster angle surface of the triple frequency crystal is adjusted to play the role of changing points.
  • the relative position of the exit point of the light outputting harmonics of the triple frequency on the Brewster angle surface of the triple frequency crystal is adjusted without causing any change in the output beam Or move to change points.
  • the relative position of the exit point of the light outputting the triple frequency harmonics on the Brewster angle of the triple frequency crystal is adjusted to play the role of point change.
  • the crystal in the front optical system and the triple frequency crystal adopt one of the following forms: LBO, LiNOb, LiTb, BBO, LKP, KD*P, ⁇ -BBO, quartz crystal , PPLN, PPTN, PPKT or other nonlinear crystals.
  • the Brewster incident or exit angle of these crystals is between or about 30-70°.
  • a quadruple frequency crystal can be used to replace a triple frequency crystal, and when the second frequency of the double frequency wave is generated, the incident double frequency harmonics are converted into the quadruple frequency harmonics.
  • the output from the Brewster angle interface of the crystal is corrected to a quadruple-frequency outgoing beam that is basically consistent with the shape of the cross-sectional light intensity distribution of the initial input fundamental beam or other shapes required.
  • the present invention can also be used to generate the fourth harmonic of the fundamental wave.
  • the incident double frequency harmonics are converted into the quadruple frequency harmonics, and they are emitted through the Brewster angle interface of the quadruple frequency crystal. It is corrected to a quadruple frequency outgoing beam that is basically consistent with the cross-sectional distribution shape of the fundamental beam that was initially input. That is, in the above process of generating a quadruple frequency beam, if the crystal 30 is a phase-matched second frequency doubler that generates a double frequency wave, that is, a quadruple frequency wave, the fourth harmonic of the fundamental wave can also be effectively generated.
  • the cross section of the fourth harmonic is also adjusted or corrected to the required beam quality. If the frequency quadruple beam has a P-polarization state, it will be completely transmitted when it exits the interface 400, and the method is equally effective. If the quadruple beam is not in the P-polarization state, the non-antireflection coated interface 400 will lose it.
  • the device for generating the triple rate of laser radiation can achieve beam quality improvement, cost reduction and final conversion of the laser frequency conversion outside the cavity, and the life of the final converted crystal is prolonged.
  • the nonlinear crystal may not need to be coated on the output surface, Ingenious design and selection of nonlinear optical frequency conversion.
  • the present invention is to generate triple frequency or other multiple frequency multiples, usually a triple frequency 355nm ultraviolet laser with a wavelength of 1064nm, or a fourth frequency multiple to generate 266nm deep ultraviolet light, and adopts simple and reliable multiple frequency conversion production
  • the solution of ultraviolet or deep ultraviolet laser beam meets the design needs of long-life, high-stability and low-cost ultraviolet lasers.
  • the invention cleverly creates the beam quality requirements for realizing the final laser frequency conversion outside the cavity by pre-setting the beam intensity distribution shape of the fundamental wave and the second harmonic before conversion, the cost is reduced, the life of the conversion crystal is prolonged, and the manufacturing is simple.
  • a compensation crystal is added to pre-compensate for the deviation angle or time between the second harmonic and the fundamental wave due to the second harmonic conversion process.
  • the delay staggered can significantly improve the efficiency of the third harmonic (3 ⁇ ) beam with the second sum frequency ( ⁇ +2 ⁇ );

Landscapes

  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)

Abstract

一种激光辐射三倍率产生的装置，包括：前部光学系统（1020）对输入的基波光束（11）的光强分布进行调整，将入射基波光束（11）转换为基波（12）和二倍频谐波（23），也使得所转换的二倍频谐波（23）的横截面光强分布形状得到调整，调整后的基波（12）和二倍频谐波（23）光束出射至三倍频晶体（30）；三倍频晶体（30）的光束出射面切割为布鲁斯特角出射界面（400），将基波（12）和二倍频谐波（23）在三倍频晶体（30）内发生和频转换，产生三倍频谐波光束（31），经过布鲁斯特角出射界面（400）后出射，转换为所需要的、或与初始输入的基波光束（11）的横截面光强分布形状基本相同的三倍频光束（32）出射。通过预先设置转换前的基波（12）和二次谐波（23）的光束强度分布形状实现腔外最终激光频率转换的光束质量要求，成本降低和转换晶体寿命延长，制作简单。

Description

激光辐射三倍率产生的装置 技术领域
本发明涉及激光技术领域，特别涉及一种激光辐射三倍率产生的装置。特别是激光光束腔外三次或四次谐波产生紫外激光辐射的装置和原理。
背景技术
近年来，特定频率激光器件的应用越来越多，紫外相干光的产生的研究和应用越来越普遍。一些应用，需要大功率或高能量，高光束质量的相干紫外光。然而，大功率或高能量的相干紫外光的产生的一种有效途径，是通过对红外相干光束的二次和三次谐波转换过程。这方面的探索和研究，可以在许多发表的刊物文献和专利或产品设计中看到。例如，Koechner所著的Solid State Laser Engineering，fourth ed.，Springer Series in Optics Sciences V.1(1996)，和专利US5408481，5384803，5295143，5047668，5034951，4510402，3873825，US5，850，407等。
对于这些应用，现有的已知增益介质可以通过气体、solid-state材料、电泵浦半导体和光泵浦，在各种功率水平和操作模式下提供所需的各种色彩激光辐射。半导体作为增益介质，用于产生紫外线、可见光和红外激光辐射。气体激光器可以产生良好的紫外线(uv)，可见光和红外线(ir)光。电子或光泵浦的半导体激光器可以在可见光频率范围内产生红外和近红外基本激光光源及其谐波。直接半导体激光辐射能产生红光和蓝光，紫外辐射具有良好的电转换效率。然而，半导体二极管激光器是不可用于直接产生高脉冲强度和高光束质量的紫外激光束，而用于线路板加工或晶圆切割等多种微电子半导体工业应用。基于腔内或腔外的三倍频的纳秒脉冲激光器设计，部分地解决了工业加工对纳秒脉冲激光器的需求。然而，随着微电子工业的不断发展，精细加工的要求越来越高，对超快脉冲激光加工的需求很大。超快脉冲激光器一般不适宜用腔内三倍频方案，几乎所有的大能量皮秒或飞秒超快脉冲紫外转换，均采用腔外的方式。这种脉冲光束腔外转换时，可直接用二次和三次谐波产生的二倍频和三倍频晶体对红外激光器输出的光束进行频率转换、产生紫外光束。精密加工所需要的激光光束，其横截面光强分布要达到一定的要求。一般腔外倍频装置产生的紫外输出光束，需要进行光斑横截面形状的调整。
由于高能量或高功率的紫外输出激光束，对于其产生的非线性晶体和调整紫外光束的光学部件会有损伤。因此，产生和调整紫外激光束的光学元器件的使用寿命有限，很难达到所需的长时间运行的要求。一种解决的办法是通过移动三倍频晶体或其他光学元件，使得被损坏的晶体或光学部件重新使用新的未损坏的光点位置。即使如此，一般来说，无论是晶体或紫外光学部件的几何大小都是有限，整个装置的使用寿命受限。
针纳秒脉冲紫外激光器输出紫外光寿命的延长，William Grossman等人在1997年发明了一种方法，发明者在美国专利US5，850，407里描述了一种从基波和二次倍频中通过三倍频转换的晶体布鲁斯特角出射时，色散引起的折射角度的不同，可以分离出三倍频光束的方法。这种方法是用一个单端布鲁斯特入射角切割的三倍频晶体，利用三倍频晶体在布鲁斯特角折射时角度偏离的色散性分开腔内产生的三倍频紫外光束，三倍频晶体的出射光束界面不需要镀膜，并且返回剩余的基波能量被再次振荡转换使用。避免了三倍频晶体需要镀三个不同波长的增透膜的复杂性和高成本。此外，腔内使用布鲁斯特角度入射的晶体时，紫外光束出射时在出射界面的光束截面变大，光密度变低，三倍频晶体寿命延长。由于腔内基波入射到倍频晶体的布鲁斯特角晶体前，基波光束具有由腔体决定的圆度，来回倍频晶体后，所产生的紫外光束，可以保持基波的基本形状。因此，此专利比较适用于腔内三倍频。如果用在腔外三倍频过程中，此专利描述的方法，将会将剩余的基波直接返回到基波产生的激光源。这样，激光源会非常不稳定，或者被剩余的强光打坏。因此，至今为止还没有任何发表的文献或产品，直接使用此专利所描述的方法到腔外三倍频中。此专利所有权的Lightwave Electronics公司在2000年后开发的另外一款皮秒紫外激光器，X-Cyte，产品系列中，使用了直接单次通过布鲁斯特角度切割的产生三倍频(和频)晶体的一个方案.但是，此产品并没有使用预先调整产生三次谐波的基波和二次谐波光束横截面强度分布，而是使用了额外的紫外光学部件对所产生的紫外光斑进行转换后的调整。此产品的设计方案复杂，成本高，没有巧妙地解决光束横截面变形的难题，而是使用了多个紫外光学元件进行转换后的光束横截面形状矫正，从而产品造加高。
发明内容
本发明的目的旨在至少解决所述技术缺陷之一。
为此，本发明的目的在于提出一种激光腔外三倍频产生的装置，用以 克服现有激光腔外三倍频装置的复杂性或高成本的缺陷，此方法也同样适用于四倍频的产生。
为了实现上述目的，本发明的实施例提供多种激光辐射三倍率产生的装置，包括：前部光学系统和三倍频晶体，其中，
所述前部光学系统中的某个光学部件的一个入射面切割为布鲁斯特入射角界面，用于对输入的基波光束的光强分布进行调整，并将所述入射基波光束转换为基波和二倍频谐波，以使得所转换的产生的基波和二倍频谐波的横截面光强分布形状得到调整，调整后的基波和二倍频谐波光束出射至所述三倍频晶体；
所述三倍频晶体的出射面切割为布鲁斯特出射角界面，将输入的所述基波和二倍频谐波在所述三倍频晶体内发生和频转换，产生三倍频谐波光束，所述三倍频谐波光束经过布鲁斯特出射角界面后出射，校正为所需的、或者是与初始输入的基波光束的横截面光强分布形状基本一致的、或着是所需要的、三倍频光束形状的光束出射。
进一步，所述入射基波光束的横截面光强分布形状为圆形，剩余的基波、二倍频谐波和所述三倍频晶体内的三倍频谐波的横截面光强分布形状为椭圆形，所述三倍频出射光束的形状为圆形。
进一步，所述前部光学系统包括至少一个二倍频晶体，用于将输入的基波光束转换为二倍频谐波和剩余基波，使得产生的剩余基波和二倍频谐波的横截面光强分布形状得到调整。
进一步，所述前部光学系统包括：补偿模块、也称为补偿晶体，接收所述基波和二倍频谐波，对所述基波和二倍频谐波实现空间上的走离角或时间上的脉冲延迟走离错开、或二者均有、进行有利于产生高品质或高转换效率的三次谐波的调整或预先补偿，以使得所述基波和二倍频谐波的光束方向在二次频率转换的三倍频晶体内部共线或同步得更好
进一步，所述二倍频晶体的出射界面采用对所述基波和二倍频谐波全透射的镀膜；
所述三倍频晶体的入射界面采用对所述基波和二倍频波入射方向镀增透膜。
进一步，所述基波和二倍频谐波通过所述补偿模块，实现空间上的走离角调整，使得所述基波和二倍频谐波的光束方向更加共线。
进一步，所述补偿模块采用以下形式之一：
(1)一块或多块晶体的组合；
(2)一个或多个成对的普通棱镜或布鲁斯特角度的棱镜；
(3)一个或多个具有延迟反射的啁啾镜；
(4)一个或多个透镜组合。
进一步，所述前部光学系统包括：过渡介质、二倍频晶体和补偿模块，其中，
所述过渡介质的入射面切割为布鲁斯特入射角界面，用于对输入的基波光束的光强分布进行调整，以对产生的基波的横截面形状进行调整，出射至所述二倍频晶体；
所述二倍频晶体将由所述过渡介质发射的基波转换为二倍频谐波，将剩余的基波和二倍频谐波出射至所述补偿模块；
所述补偿模块接收所述基波和二倍频谐波的入射，对所述基波和二倍频谐波实现空间上的走离角的调整，以使得所述基波和二倍频谐波的光束，在产生三倍频转换时，在空间上重叠更好。
进一步，所述二倍频晶体对所述基波和二倍频谐波产生时间上的脉冲延迟错开，所述补偿晶体对所述基波和二倍频谐波，实现时间上的相对延迟调整，以使得所述基波和二倍频谐波的光束，在产生三倍频转换时，在时间上重叠更好。
进一步，所述前部光学系统包括：二倍频晶体、过渡介质和补偿模块，其中，
所述二倍频晶体将入射的基波光束转换为基波和二倍频谐波，将所述基波和二倍频谐波出射至所述过渡介质；
所述过渡介质的入射面切割为布鲁斯特入射角界面，用于对输入的基波和基波产生的二倍频谐波的光强分布进行调整，以对产生的基波和二倍频谐波的横截面形状进行调整，出射至所述补偿模块；
所述补偿模块接收所述基波和二倍频谐波的入射，对所述基波和二倍频谐波实现空间上的走离角或时间上的脉冲延迟错开进行调整。
进一步，所述前部光学系统包括部分或全部的：三倍频晶体、二倍频晶体和光学反射部件，所述三倍频晶体的一个界面切割为布鲁斯特角界面，兼具作为所述基波光束入射面，其中，
所述基波光束入射至所述三倍频晶体的布鲁斯特角界面，对输入的基波光束的光强分布进行调整，出射至所述二倍频晶体；
所述二倍频晶体将由所述三倍频晶体调整的基波转换为二倍频谐波，将剩余的基波和二倍频谐波出射至所述光学反射部件；
所述光学反射部件将所述基波和二倍频谐波反射转折后，再次进入所述二倍频晶体，由所述二倍频晶体再次通过，将剩余的基波和二倍频谐波出射至所述三倍频晶体；
由所述三倍频晶体将输入的所述基波和二倍频谐波在所述三倍频晶体内发生和频转换，产生三倍频谐波，所述三倍频谐波经过所述三倍频晶体的布鲁斯特角界面后出射，校正为与初始输入的基波光束的横截面光强分布形状基本一致、或所需要、的三倍频出射光束。
进一步，所述光学反射部件采用以下形式之一：
(1)反射镜面；
(2)一组一个或多个镜面组成的集合部件；
(3)一个锥形反射镜；
(4)一个相位共轭反射镜片。
进一步，所述前部光学系统还包括：补偿晶体，所述补偿模块位于三倍频晶体和所述二倍频晶体之间，用于对经过所述基波和二倍频谐波实现空间上的走离角和时间上的脉冲延迟走离错开进行调整。
进一步，通过平行移动所述二倍频晶体或调整输入基波横截面光束强度分布的其他透明介质，以调整输出所述三倍频谐波的光在三倍频晶体出射点的相对位置，起到换点的作用。
进一步，通过平行移动所述三倍频晶体，调整输出所述三倍频谐波的光在三倍频晶体出射点的相对位置，起到换点的作用。
进一步，通过沿着所述三倍频晶体的布鲁斯特面平行移动所述三倍频晶体，调整输出所述三倍频谐波的光在三倍频晶体布鲁斯特角面上出射点的相对位置，不引起输出光束的任何变化或移动，起到换点的作用。
进一步，通过平移或转动所述补偿模块补偿晶体，调整输出所述三倍频谐波的光在三倍频晶体布鲁斯特角面上出射点的相对位置，起到换点的作用。
进一步，所述前部光学系统中的晶体和所述三倍频晶体采用以下形式之一：LBO，LiNOb，LiTb，BBO，LKP，KD*P，α-BBO，石英晶体，PPLN，PPTN，PPKT或其他晶体。
进一步，所述三倍频晶体采用相位匹配产生二倍频波的二次倍频时，将入射的二倍频谐波转换为四倍频谐波，经过所述三倍频晶体的布鲁斯特角界面出射，校正为与初始输入的基波光束的横截面光强分布形状基本一致、或所需要、的四倍频出射光束。
根据本发明实施例的激光辐射三倍率产生的装置，可以实现腔外二次激 光频率转换的光束质量改善，省去对紫外光束形状整形的需要，成本降低，三倍频晶体寿命延长，激光产生三次谐波的非线性晶体不需要在输出面镀膜，实现非线性频率转换。本发明在产生三倍频或其他多次倍频，通常，但不限于，为1064nm波长的三倍频355nm的紫外激光，或四次倍频产生266nm的、或其他次谐波的、深紫外光，采用简单而可靠的多次倍频转换生产紫外或深紫外激光光束的方案，满足长寿命、高稳定性和低成本的紫外激光器的需要。
本发明实施例的激光辐射三倍率产生的装置，具有以下有益效果：
1)使用了布鲁斯特角度出射的三倍频晶体形状，使得光束在出射点处的光束直径变大，光强度变小，晶体受紫外光照射后的寿命变长；
2)使用了经过布鲁斯特角度切割的布鲁斯特角出射或入射，在进行三倍频转换过程中，可以比较容易地调整所产生的三倍频紫外光束横截面强度分布。基本保持基波光束的横截面形状，无需进行复杂的紫外三倍频光束横截面光束强度分布形状的调整，减少了对多个紫外光学部件的需要，降低了成本，提高了产品的可靠性和稳定性；
3)在第一次倍频和第二次和频过程中间，加入补偿模块，预先补偿二次谐波和基波之间的由于谐波转换过程中产生的走离角或时间上的延时错开，能够明显提高第二次频率转换，产生三次谐波的三倍频(3ω)或四次谐波(4ω)光束，的效率；
4)使用布鲁斯特角度的倍频晶体，使得布鲁斯特角度切割截面不需要光学镀膜，使得具有布鲁斯特角度的晶体制造简单，而且成本低。
本发明附加的方面和优点将在下面的描述中部分给出，部分将从下面的描述中变得明显，或通过本发明的实践了解到。
附图说明
本发明的上述和/或附加的方面和优点从结合下面附图对实施例的描述中将变得明显和容易理解，其中：
图1为根据本发明实施例的激光辐射三倍率产生的装置的结构图；
图2为根据本发明实施例的采用二倍频晶体和补偿模块的激光辐射三倍率产生的装置的结构图；
图3为根据本发明实施例的采用光学反射部件的激光辐射三倍率产生的装置的结构图；
图4为根据本发明实施例的采用过渡介质、二倍频晶体和补偿晶体的激光辐射三倍率产生的装置的结构图。
具体实施方式
下面详细描述本发明的实施例，实施例的示例在附图中示出，其中自始至终相同或类似的标号表示相同或类似的元件或具有相同或类似功能的元件。下面通过参考附图描述的实施例是示例性的，旨在用于解释本发明，而不能理解为对本发明的限制。
本发明提供一种激光辐射三倍率产生的装置，适用于腔外和腔内，可以产生紫外激光光束的三倍频激光。本发明通过一个布鲁斯特角出射界面的介质的频率转换装置，联合倍频晶体或其他介质，预先调整输入光束和中间产生的谐波光束的横界面光强形状、并可能包括调整相互作用的各光束之间的走离角度、并可能包括调整时间延迟，再进行紫外频率转换，经过一个布鲁斯特角出射面，使得所产生的紫外输出光束横截面光强分布得到调整和达到较佳的转换效率。
【第一实施例】
如图1所示，本发明实施例的激光辐射三倍率产生的装置，包括：前部光学系统和三倍频晶体。
前部光学系统1020，用于对输入的基波光束的光强分布进行调整，并将基波光束转换为基波和二倍频谐波，以使得产生的基波和二倍频谐波的横截面光强分布形状得到调整，调整后的基波和二倍频谐波出射至三倍频晶体。该前部光学系统1020可以采用透明的入射介质，其入射界面等于或近似等于此透明介质布鲁斯特角度入射角切割为较佳的选值。
三倍频晶体30的出射面切割为布鲁斯特出射角界面，将输入的基波和二倍频谐波在三倍频晶体内发生和频转换，产生三倍频谐波，三倍频谐波经过布鲁斯特出射角界面后出射，校正为与初始输入的基波光束的横截面光强分布形状基本一致的，或所需要的，三倍频出射光束。该三倍频晶体30相位匹配在产生三次谐波的角度方向切割，并且具有至少出射三次谐波的界面是布鲁斯特角度安排出射光束。
具体来说，选择适当的前部光学系统1020，实现基波光束和转换成二倍频谐波光束的横截面形状，使得输入的基波光束11经过前部光学系统1020后所产生的二倍频谐波23和剩余基波12的横截面光强分布得到调整后，高效率地产生最终所需的三倍频或四倍频谐波31，在最终离开转换装置的近似布鲁斯特角度出射界面400后，三倍频或四倍频光束32以P-偏振状态出射离开界面400，并且其横截面的光强分布，得到优化。由于出射面近似在布 鲁斯特角度，界面400不需要镀增透膜涂层并对P-偏振的三倍频或四倍频光束损失很小，并且光束在界面上面积增大后，光照强度减弱，使得界面受紫外光束照射的寿命得到延长。
在本发明的实施例中，一种常用情形是，基波光束的横截面光强分布形状为圆形，基波、二倍频谐波和三倍频晶体内的三倍频谐波的横截面光强分布形状为椭圆形，三倍频出射光束的形状为圆形。即，基波光束11的横截面光强分布形状为圆形，为圆对称光束，经过前部光学系统1020的布鲁斯特角度入射的安排，调整基波11的形状，使得产生的剩余基波12和二倍频光束23的形状为椭圆形，剩余基波12和二倍频光束23再入射到三倍频晶体30，其中三倍频晶体30的界面300对剩余基波12和二倍频光束23的形状不进行改变，对基波12和二倍频光束23进行转换生成三倍频光束31，
产生的三倍频光束31和光束12的横截面形状接近，从三倍频晶体30的界面400的布鲁斯特角度出射后，产生的最终紫外光束32校正到期望的圆形，光束32可以基本保持基波光束11的形状。在出界面400出射后，光束32的光强分布达到所需的横截面光强分布形状。
本实施例所需的装置，由于是预先对入射的基波光束横截面光强分布或是基波和产生的二倍频谐波光束强度分布进行调整，所需的办法相对于调整最终输出的紫外光束要简单许多，实用且造价低。由于最终输出的紫外光束不需要利用光学部件进行调整，紫外光束对部件损伤的可能性降低，使得整个系统的使用寿命变长。本发明包含至少一个近似为布鲁斯特角度出射界面的装置(三倍频晶体30)，紫外光束出射后，所需要产生的谐波输出光束的横截面光强分布可以达到所需要的理想光强度分布。
需要说明的是，本实施例通过适当选择前部光学系统1020，可以包括或不包括基波和二倍频谐波的空间走离角度的、或基波和二倍频谐波在时间上的走离错开的、全部或部分补偿或调整。
其中，前部光学系统1020的入射界面100和三倍频晶体的出射界面400均为布鲁斯特界面，不一定需要镀增透膜。
本实施例的可用于腔外或腔内的三倍频激光装置，使用布鲁斯特角度入射的调整输入基波横截面光束强度分布的透明介质，和布鲁斯特角度切割的介质，使得以布鲁斯特角度入射或出射的基波和三次谐波，在腔外光束经过非线性转换晶体二次的三倍频出射离开三倍频晶体后，抵消全部或部分因为布鲁斯特入射面里的光束直径的变化，调整或基本保持原入射基波的横截面形状或强度分布，使得最终出射的三倍频光束横截面形状和原来入射基波形 状基本一致，或达到预期的光束形状。
【第二实施例】
在本实施例中，前部光学系统采用二倍频晶体20，二倍频晶体20的入射面切割为布鲁斯特入射角界面，使得界面100不需要镀增透膜也会对P-偏振入射的基波在布鲁斯特角度入射时无损失。
二倍频晶体20用于将输入的基波光束转换为二倍频谐波和剩余基波，使得产生的剩余基波和二倍频谐波的横截面光强分布形状得到调整，调整后的基波和二倍频谐波出射至三倍频晶体。二倍频晶体的入射角界面100等于或近似等于此晶体的布鲁斯特角度入射角切割，其布鲁斯特面作为入射面100时，不需要镀增透膜。
二倍频晶体20的出射界面200采用对基波和二倍频谐波全透射的镀膜。如果基波和二次倍频波可以为同一种P-偏振，界面200也可以，但不一定要，设计成布鲁斯特出射角度。需要说明的是，如果基波和二倍频波的偏振方向不同，一般使用正对入射时需要镀增透膜。
三倍频晶体300的出射面400切割为布鲁斯特出射角界面，将输入的基波和二倍频谐波在三倍频晶体内发生和频转换，产生三倍频谐波，三倍频谐波经过布鲁斯特出射角界面后出射，校正为与初始输入的基波光束的横截面光强分布形状基本一致的三倍频出射光束。在本实施例中，三倍频晶体的入射界面采用对基波和二倍频波全透射的镀膜，在正对入射几何形态镀增透膜。三倍频晶体30选择为基波和二倍频光束的和频(频率相加：(ω+2ω))相位匹配，并使得所产生的三倍频(3ω)光束在界面400出射时为P-偏振、沿着布鲁斯特角度出射。
三倍频晶体30相位匹配在产生三次谐波的角度方向切割，并且具有至少出射三次谐波的界面是布鲁斯特角度安排出射光束，出射布鲁斯特界面400并不一定需要镀增透膜。
本发明的激光三倍频激光装置用于在腔外，让需要二次倍频后产生三倍频(或四倍频)的相关激光束，沿着二个布鲁斯特角切割的晶体在布鲁斯特角度入射和出射的布鲁斯特截面至少二次，进行有效三倍频(或四倍频)激光束产生，巧妙地纠正单次或奇数次通过具有布鲁斯特角切割面的晶体时，引起的出射光束横截面对称性相比较于原来入射光束横截面光强分布的明显改变。利用激光束在腔外的布鲁斯特界面的折射角度随波长的改变(角度色散)，从基波和二倍频波中分离出三倍频(或四倍频)光束。这种方法，对于P-偏振的三倍频(或四倍频)光束，具有全透射而且不需要镀增透膜。
具体来说，输入基波光束11为圆对称光束，经过这样的装置后，通过二倍频晶体20的布鲁斯特入射界面，使得光束12和光束23调整为椭圆形的光束形状。在进一步的和频产生过程中，所产生的三倍频光束31，在晶体30里面为椭圆形状。光束31经过界面400最终输出的布鲁斯特角度出射后，变成光束横截面为圆形的圆对称光强分布，而不是明显的非圆形强度分布。从而，省去需要校正紫外激光光束圆度的后续光学系统。
本实施例首先对基波光束11使用布鲁斯特角度入射的二倍频晶体20，和布鲁斯特角度切割的三倍频晶体30，使得以布鲁斯特角度入射或出射的基波和三次谐波，在腔外光束经过非线性转换晶体二次和三倍频出射离开三倍频晶体30后，抵消全部或部分因为布鲁斯特入射面里的光束直径的变化，调整或基本保持原基波的横截面形状或强度分布，使得最终出射的三倍频光束横截面形状和原来基波形状基本一致或近似一致。本发明通过光学球面和柱面透镜组合，对原先的光束横截面形状也可以进行调整，譬如调整为在出射的布鲁斯特界面的光线入射面里的光束半径比它的垂直方向上明显宽的椭圆横截面光强分布，使得最终所产生的紫外输出光束的横截面光束大小在上面所述的二个正交垂直方向上的大小相等，或满足所需要的光斑形状。
本实施例的装置一般用于在激光腔外，让需要二次倍频后产生三倍频或四倍频的激光束，沿着最后一个产生谐波输出的一个非正入射的面，通常为近布鲁斯特角度出射面400、出射时，由于近布鲁斯特角度出射的p-偏振光在出射端面的光斑变大，此面所承受的紫外光强度变小，并且此布鲁斯特角面400对p-偏振的光具有无需镀增透膜就能够全透射的特点，使得装置的整体使用寿命变长，制造成本变小。
另外，前部光学系统1020还可以设计二倍频晶体或单独的晶体介质，对所产生的基波和二倍频谐波的相对走离角度进行调整，使得它们在进一步测试产生和频作用时，共线度得到改善，使得转换效率得到提高。在超短脉冲光束进行频率转换过程中，还可以设计一种补偿介质，用以对基波和二倍频谐波之间的时间延迟错开进行补偿和调整，使得它们在进一步产生和频混合作用时，时间重叠度得到改善，使得转换效率得到提高，省略了对紫外光束圆度需要进一步校正而带来的困难和所需的高价格的紫外光学校正元件，也减少了影响装置寿命的调整紫外光束的光学元件，从而，延长了整个激光频率转换装置的寿命，并降低了装置的造价。
针对上述提供空间和时间上走离，在上述二倍频晶体20的基础上，前部光学系统还可以包括、但不是必须包括、补偿晶体40。
二倍频晶体20的入射面切割为布鲁斯特入射角界面100，将输入的基波光束转换为基波和二倍频谐波，使得产生的基波12和二倍频谐波22的横截面光强分布形状得到调整；补偿晶体40接收基波12和二倍频谐波22的入射，对基波12和二倍频谐波22实现空间上的走离角进行补偿或预先补偿，提高三倍频谐波32的出光效率。
基波12和二倍频谐波22在时间上的走离的调整，利用其群速度的不同，对基波12和二倍频谐波22在时间上走离进行调整，使得基波12和二倍频谐波22的能量传播在时间上重叠得到优化而适合产生高效率的脉冲紫外光束。
上述方式可以衍生出多种特殊的装置，来实现无需使用多个耐紫外光的光学元件对紫外光强度分布进行进一步的调整。
一种装置，选值补偿晶体的设计，使得基波12和二倍频谐波22产生后，光束经过补偿晶体40，实现空间上的走离角的补偿或预先补偿，使得基波12和二倍频谐波22的光束在三倍频晶体内部传播方向共线，以校正光束方向。空间走离角度的调整，可以通过补偿晶体40对基波12和二倍频谐波22折射角度不同的调整，使得基波12和二倍频谐波22的能量传播在空间上重叠得到优化而适合产生高效率和高品质的光束强度分布的紫外光束。
在本发明的实施例中，补偿模块40可以采用对基波和二次谐波透明的双折射晶体。如切割取向在一些特定的角度的LBO，LiNOb，LiTb，KD*P，α-BBO BBO，LKP，KD*P，α-BBO，石英晶体等。
补偿模块40采用以下形式之一：
(1)一块或多块晶体的组合；
(2)一个或多个普通棱镜或布鲁斯特角度的棱镜；
(3)一个或多个具有延迟反射的啁啾镜；
(4)一个或多个透镜或反射镜的组合。
如图2所示的图，工作原理描述如下：基波光束11具有常规的圆对称的横截面光强度分布。基波光束11在入射到二倍频晶体20的布鲁斯特角界面100后，横截面由圆形转换为椭圆形，经过折射后进入二倍频晶体晶体20，在晶体20通过时，得到相位匹配而有效地第一次转换成二倍频激光光束22，而从界面200出射离开晶体20。光束11的横截面大小，由于以布鲁斯特角度入射，变成基波光束12，基波光束12的一个方向里的光束直径比原光束11在入射光线和端面100的法线所组成的入射面里的直径变大。光束11经过晶体20后，变成基波12和二倍频谐波22入射到补偿晶体40，经过补偿晶体40后，基波12和二倍频谐波22的二束光的走离角或者在时间上的走离 错开，由设计的晶体40的角度或温度或其他特性的调整而得到所需要的空间或时间或二者都有的适当调整，使得它们在经过界面300进入三倍频晶体晶体30内部第二次转换出三倍频时在空间上更加重叠或时间上更加同步或二者均有，在晶体30内部更加有效地进行第二次频率转换成三次谐波，产生三倍频光束31。光束31经过布鲁斯特角界面400后，光束的横截面形状由椭圆形校正为圆形，变成三倍频谐波光束32。三倍频谐波光束32的横截面在纸面里的光束直径，被布鲁斯特界面折射后缩小，并由于色散产生的角度，与剩余基波光束16和剩余二倍频光束25以不同的出射角度分离，离开界面400，经过一定距离传播后，可以被进一步有效分离，并使得光束横截面大致恢复到原先基波入射时的形状或保持所需要的真度，也使得产生的三次谐波光束32被容易地分离出装置。
其中，界面100和界面400的布鲁斯特角度基本一致。因此，光束11不需要经过复杂的校正，就可以实现转换为横截面为原形的三倍频谐波光束32。
这种方式主要具有以下四个优点：
(1)三倍频光束在界面400斜面上的截面宽，使得因为光束32照射的三倍频晶体寿命长，不需要经过后续校正，即可达到期望形状；
(2)界面400不需要额外镀膜，大大降低了成本；
(3)三倍频光束32、剩余基波光束16和剩余二倍频光束25以不同的出射角度分离，离开界面400，在空间自动实现分离；
(4)选用晶体20和晶体30的材料、晶体界面100和界面400的布鲁斯特角度基本一致，使得基波光束11和三倍频谐波32形状基本一致，满足后续应用的需要。
本发明提供的上述实施例，使用布鲁斯特角度入射的二倍频晶体20或调整输入基波横截面光束强度分布的其他透明介质，和布鲁斯特角度切割的三倍频晶体30，使得以布鲁斯特角度入射或出射的基波和三次谐波，在腔外光束经过非线性转换晶体二次后产生的三倍频光束折射离开三倍频晶体30后，抵消全部或部分因为布鲁斯特入射面里的光束直径的变化，调整或基本保持原基波的横截面形状或强度分布，使得最终出射的三倍频光束横截面形状和原来基波形状基本一致或近似一致。并且，也可以额外在两次光束频率转换过程之间安排、或不安排、一个可以调节基波和二次谐波的走离角或时间错开的补偿晶体40。
在本发明的实施例中，二倍频晶体20、三倍频晶体30和补偿晶体40可以选择，如LBO，BBO，α-BBO，石英晶体，LiNOb，KTP，PPLN，PPKTP， PPTN等多种非线性激光晶体或者他们的组合，切割在不同的方向，实现相位匹配或空间或时间补偿所需的角度。补偿模块可以是补偿晶体或其他光学部件等。
【第三实施例】
图3描述了一种类似于图2的设计，主要不同是将图2的设计，通过反向第二次通过布鲁斯特角切割的界面，使得原先入射光束11的横截面光束形状，出射的三倍频激光束32基本保持一样的或相近的形状，再输出。这样输出光束不需要因为第二次倍频时，由单次出射布鲁斯特角界面时的光束横截面圆度变化而需要进行额外的光束横截面光束强度进行矫正。需要指出的是，这里首次通过的布鲁斯特角度部件，也可以是一个单独的、具有预先调整光束横截面光强分布的光学部件，与三次谐波产生的和频晶体分开。
在本实施例中，前部光学系统包括：三倍频晶体30、二倍频晶体20和光学反射部件02，三倍频晶体30的一个界面切割为布鲁斯特角界面400，兼具基波光束入射面以及基波和二次谐波的出射面.
基波光束入射至三倍频晶体30的布鲁斯特角界面400，对输入的基波光束111的光强分布进行调整，以对产生的基波的横截面形状进行调整，出射至二倍频晶体20。二倍频晶体20将由三倍频晶体30发送的基波转换为二倍频谐波，将剩余的基波和二倍频谐波出射至光学反射部件。光学反射部件02将基波和二倍频谐波反射转折后，再次进入二倍频晶体，由二倍频晶体在基波二次通过时进行二倍频转换以产生二倍频谐波，将剩余的基波和二倍频谐波出射至三倍频晶体30的另一界面300。由三倍频晶体30将输入的基波和二倍频谐波在三倍频晶体30内发生和频转换，产生三倍频谐波，三倍频谐波经过三倍频晶体30的布鲁斯特角界面400后出射，校正为与初始输入的基波光束的横截面光强分布形状基本一致的三倍频出射光束32。
在本发明的实施例中，光学反射部件02采用以下形式之一：
(1)反射镜面；
(2)一组多个反射镜面组成的集合部件；
(3)一个锥形反射镜；
(4)一个相位共轭反射镜片。
进一步，前部光学系统还可以、但不是必须、包括：补偿模块、或称为补偿晶体、40，补偿晶体40位于三倍频晶体30和二倍频晶体20之间，用于对经过基波和二倍频谐波实现空间上的走离角和时间上的脉冲延迟走离错开进行补偿。
补偿模块，接收所述基波和二倍频谐波，对所述基波和二倍频谐波实现空间上的走离角或时间上的脉冲延迟走离错开、或二者均有、进行有利于产生高品质或高转换效率的三次谐波的调整或预先补偿，以使得所述基波和二倍频谐波的光束方向在二次频率转换的三倍频晶体内部共线或同步得更好。
参考图3，本实施例的工作原理如下：入射光束基波111，假设具有圆形的横界面形状的光束强度分布，进入三倍频晶体30的布鲁斯特角度界面400，以布鲁斯特角入射进入晶体30后，在晶体30里面变成椭圆形横截面形状的光束强度分布，通过晶体30的正入射界面300后出射的光束112依然是椭圆形状，再经过晶体40，进入二倍频晶体20，产生二倍频光束21。其中，二倍频光束21的横截面形状为椭圆形。
光学反射部件02使得基波(频率为ω)的光束112和二倍频(频率为2ω)光束21经过180度或近似180度反射转折后，再次进入二倍频晶体20和补偿晶体40，入射到三倍频晶体30的界面300内。二倍频晶体20在基波112二次通过时，产生二倍频(2ω)转换。基波112和二次谐波22，继续以椭圆形横截面光束15和椭圆形横截面二次谐波光束24在晶体30的相位匹配情况下，发生和频(ω+2ω)的第二次频率转换，产生椭圆形横截面的三倍频(3ω)光束光束31。椭圆形的光束31经过布鲁斯特角界面400后，由于以布鲁斯特角度出射，光束31的横截面出射离开界面400后，在布鲁斯特入射面内的光束直径发生调整，变成具有或接近具有原基波的原始光束圆度的三倍频光束32。
这样，初始基波111为圆形横截面的光束，经过二个布鲁斯特角入射和出射的截面后，所产生的三倍频光束32会以基本的圆形横截面光束形状离开。这种装置输出的三倍频光束32，除了因为倍频过程中，横截面的光束形状因非线性转换的相位匹配形成的一些变化外，能够基本保持原来入射的基波光束的横截面的形状，在基波111所需要的一定的形状输入后，所产生的三倍频输出光束32，可以达到设计所需的圆度而不再需要进行光束横截面形状的调整。因为对基波的光束形状调整相对于对三倍频的紫外光束调整来得容易很多，这种方案的设计巧妙简单，制造成本低。由于无需使用额外光学部件对三倍频光束横截面进行进一步调整，结构简单，稳定性高。由于使用了布鲁斯特角度入射的晶体，在晶体内部和表面的基波、二倍频和三倍频光束照射的横截面变大，三倍频晶体寿命变长。整个装置使用寿命延长。
【第四实施例】
具体的，参考图4，前部光学系统包括：过渡介质10、二倍频晶体20和 补偿晶体40。其中，过渡介质10来预先设置输入的基波横截面形状，只要为透明介质即可。
过渡介质10的入射面切割为布鲁斯特入射角界面，用于对输入的基波光束的光强分布进行调整，出射至二倍频晶体20；二倍频晶体20将由过渡介质10发射的基波转换为二倍频谐波，将剩余的基波和二倍频谐波出射至补偿晶体40；补偿模块40接收基波和二倍频谐波的入射，对基波和二倍频谐波实现空间上的走离角或时间上的脉冲延迟走离错开进行预先设置和补偿。补偿模块40对基波和二倍频谐波实现空间上的走离角或脉冲延迟走离错开进行补偿后，以使得基波和二倍频谐波的光束方在空间或时间上重叠更好。
过渡介质具有至少一个界面为布鲁斯特角度切割，对入射的光束横截面光斑形状进行调整，使得所调整的基波光束具有有利于产生所需要的输出光束最终光斑形状的、和频转换所需的、二次谐波光束和剩余基波光束。
需要说明的是，二倍频晶体20和过渡介质10的位置顺序可以调换。即，前部光学系统包括：二倍频晶体20、过渡介质10和补偿晶体40。即，过渡介质10的入射面切割为布鲁斯特入射角界面，用于对输入的基波和二倍频谐波的光强分布进行调整，出射至补偿晶体40；补偿晶体40接收基波和二倍频谐波的入射，对基波和二倍频谐波实现空间上的走离角或时间上的脉冲延迟错开进行补偿。
此外，本发明的前部光学系统包括：三倍频晶体、二倍频晶体和光学反射部件，三倍频晶体的一个界面切割为布鲁斯特角界面，兼作为基波光束第一次的入射面。基波光束入射至三倍频晶体的布鲁斯特角界面，对输入的基波光束的横截面光强分布进行调整，出射至二倍频晶体。二倍频晶体将由三倍频晶体调整的基波转换为二倍频谐波，将剩余的基波和二倍频谐波出射至光学反射部件。光学反射部件将基波和二倍频谐波反射转折后，再次进入二倍频晶体，由二倍频晶体再次通过时进行二倍频转换以产生二倍频谐波，将剩余的基波和二倍频谐波出射至三倍频晶体。由三倍频晶体将输入的基波和二倍频谐波在三倍频晶体内发生和频转换，产生三倍频谐波，三倍频谐波经过三倍频晶体的布鲁斯特角界面后出射，校正为与初始输入的基波光束的横截面光强分布形状基本一致或所需形状的三倍频出射光束。
如图4所示，本实施例采用一种折射率和介质30相近或一样的光学透明的过渡介质10，并将介质的一个界面制作为布鲁斯特角度的入射面，使得入射光束的横截面在进入二次频率转换晶体30时，所产生的三次谐波，经过三倍频晶体30出射时，三倍频晶体的输出光束的横截面光强分布形状基本保持 输入光束的横截面光强分布形状特征。
在本实施例的装置，假设入射波截面光强分布形状为圆对称的基波光束11，以近似或等于布鲁斯特入射角折射进入过渡介质10后，基波光束11横截面强度分布形状变成椭圆形截面的光束12。光束12进入二倍频晶体20，光束12经过二倍频晶体20进行谐波转换时，产生类似光束12横截面形状的二次谐波(二倍频)光束22。光束12和二倍频谐波光束22通过设计的补偿晶体40时，相互间的走离角或时间错开延迟，受到补偿晶体40的恰当调整后，使得光束23进入二次转换产生三倍频(和频)晶体30产生更加有效的和频光束31，产生的三倍频光束31的横截面光强分布的形状也是椭圆形状，并大致具有经过界面100调整的基波12的椭圆形状。椭圆形横截面的光束31经过界面400，当界面布鲁斯特角度斜面和光束31的长短轴方向配合一致时，可以使得光束31在经过布鲁斯特角界面以布鲁斯特角度在界面400出射后，光束31的横截面，被界面400调整为三倍频光束32。三倍频光束32的横截面光强分布可以达到和原始的入射光束11的圆度特征基本一致。
由此，本发明可以通过调整输入基波的横截面光强分布的对称性，得到所需的三倍频输出光束的横截面光强分布。采用本发明可以避免对三倍频，通常为紫外波长的光束，需要进行光束形状调整的复杂光学装置和需要克服此类光学装置受紫外光照射后的短寿命的困难。通过这个发明的方法，所得到的三倍频紫外输出光的装置，输出面无需镀对三次谐波的增透膜，装置简单，成本低，性能稳定，寿命长等优点。
需要说明的是，在本发明的上述所有实施例中，通过平行移动所述二倍频晶体或调整输入基波横截面光束强度分布的其他介质，以调整输出所述三倍频谐波的光斑在三倍频晶体出射点的位置，起到换点的作用。
通过适当平行移动三倍频晶体，调整输出三倍频谐波的光在三倍频晶体出射点的相对位置，起到换点的作用。
通过平移或转动所述补偿晶体或过度介质，调整输出所述三倍频谐波的光在三倍频晶体布鲁斯特角面上出射点的位置，起到换点的作用。
通过沿着三倍频晶体的布鲁斯特面平行移动三倍频晶体，调整输出三倍频谐波的光在三倍频晶体布鲁斯特角面上出射点的相对位置，不引起输出光束的任何变化或移动，起到换点的作用。
通过适当平移或转动补偿晶体，调整输出三倍频谐波的光在三倍频晶体布鲁斯特角面上出射点的相对位置，起到换点的作用。
在本发明的上述所有实施例中，前部光学系统中的晶体和所述三倍频晶 体采用以下形式之一：LBO，LiNOb，LiTb，BBO，LKP，KD*P，α-BBO，石英晶体，PPLN，PPTN，PPKT或其他非线性晶体。这些晶体的布鲁斯特入射或出射角度在30-70°之间或左右。
在本发明中，可以四倍频晶体替代三倍频晶体，产生二倍频波的二次倍频时，将入射的二倍频谐波转换为四倍频谐波，经过所述四倍频晶体的布鲁斯特角界面出射，校正为与初始输入的基波光束的横截面光强分布形状基本一致或所需要其他形状的四倍频出射光束。
此外，本发明也可以用于产生基波的四次谐波。具体的，三倍频晶体采用相位匹配产生二倍频波的二次倍频时，将入射的二倍频谐波转换为四倍频谐波，经过四倍频晶体的布鲁斯特角界面出射，校正为与初始输入的基波光束的横截面分布形状基本一致的四倍频出射光束。即，以上产生四倍频光束的过程，如果晶体30是一个相位匹配产生二倍频波的二次倍频，即四倍频波，也可以有效地产生基波的四次谐波。在这种情况下，四次谐波的横截面也得到调整或纠正为所需的光束质量。如果四倍频光束具有P-偏振态，其出射界面400时，也是会全透射，方法同样有效。如果四倍频光束不是P-偏振态，非镀增透膜的界面400对它会有损失。
根据本发明实施例的激光辐射三倍率产生的装置，是可以实现腔外二次激光频率转换的光束质量改善、成本降低和最终转换的晶体寿命延长、非线性晶体可能不需要在输出面镀膜、非线性光频率转换的巧妙设计和选择。本发明为产生三倍频或其他多次倍频，通常为1064nm波长的三倍频355nm的紫外激光，或四次倍频产生266nm的深紫外光，采用简单而可靠的多次倍频转换生产紫外或深紫外激光光束的方案，满足长寿命、高稳定性和低成本的紫外激光器的设计需要。本发巧妙的明创造了通过预先设置转换前的基波和二次谐波的光束强度分布形状达到实现腔外最终激光频率转换的光束质量要求，成本降低和转换晶体寿命延长，制作简单。
本发明实施例的激光辐射三倍率产生的装置，具有以下有益效果：
1)使用了布鲁斯特角度出射的三倍频晶体形状，使得光束在出射点处的光束直径变大，光强度变小，晶体受紫外光照射后的寿命变长；
2)使用了二次或偶数次经过布鲁斯特角度切割的布鲁斯特角出射或入射，在进行三倍频转换过程中，可以较容易地调整所产生的三倍频紫外光束横截面强度分布。基本保持基波光束的横截面形状，无需进行复杂的紫外三倍频光束横截面强度分布的调整，减少了对多个紫外光学部件的需要和可能的损坏，降低了成本，提高了产品的可靠性和稳定性；
3)在第一次倍频和第二次倍频过程中间，加入补偿晶体，预先补偿二次谐波和基波之间的由于二次谐波转换过程中产生的走离角或时间上的延时错开，能够明显提高第二次和频(ω+2ω)产生三次谐波的三倍频(3ω)光束的效率；
4)使用布鲁斯特角度的倍频晶体，使得布鲁斯特角度切割截面不需要光学镀膜，使得具有布鲁斯特角度的晶体制造简单，而且成本低。
在本说明书的描述中，参考术语“一个实施例”、“一些实施例”、“示例”、“具体示例”、或“一些示例”等的描述意指结合该实施例或示例描述的具体特征、结构、材料或者特点包含于本发明的至少一个实施例或示例中。在本说明书中，对上述术语的示意性表述不一定指的是相同的实施例或示例。而且，描述的具体特征、结构、材料或者特点可以在任何的一个或多个实施例或示例中以合适的方式结合。
尽管上面已经示出和描述了本发明的实施例，可以理解的是，上述实施例是示例性的，不能理解为对本发明的限制，本领域的普通技术人员在不脱离本发明的原理和宗旨的情况下在本发明的范围内可以对上述实施例进行变化、修改、替换和变型。本发明的范围由所附权利要求及其等同限定。

Claims (10)

  1. 一种激光辐射三倍率产生的装置，其特征在于，包括：前部光学系统和三倍频晶体，其中，
    所述前部光学系统，用于对输入的基波光束的光强分布进行调整，并将所述入射基波光束转换为基波和二倍频谐波，也使得所转换的二倍频谐波的横截面光强分布形状得到调整，调整后的基波和二倍频谐波光束出射至所述三倍频晶体；
    所述三倍频晶体的光束出射面切割为布鲁斯特角出射界面，将输入的所述基波和二倍频谐波在所述三倍频晶体内发生和频转换，产生三倍频谐波光束，所述三倍频谐波光束经过布鲁斯特角出射界面后出射，转换为所需的、或者是与初始输入的基波光束的横截面光强分布形状基本相同的三倍频光束出射。
  2. 如权利要求1所述的激光辐射三倍率产生的装置，其特征在于，所述前部光学系统包括至少一个二倍频晶体，用于将输入的基波光束转换为二倍频谐波和剩余基波，使得产生的剩余基波和二倍频谐波的横截面光强分布形状得到调整。
  3. 如权利要求1所述的激光辐射三倍率产生的装置，其特征在于，所述入射基波光束的横截面光强分布形状为圆形，剩余的基波、二倍频谐波和所述三倍频晶体内的三倍频谐波的横截面光强分布形状为椭圆形，所述三倍频出射光束的形状为圆形。
  4. 如权利要求1所述的激光辐射三倍率产生的装置，其特征在于，所述前部光学系统包括：补偿模块，
    所述补偿模块，接收所述基波和二倍频谐波，对所述基波和二倍频谐波实现空间上的走离角或时间上的脉冲延迟走离错开、或二者均有、进行有利于产生高品质或高转换效率的三次谐波的调整或预先补偿，以使得所述基波和二倍频谐波的光束方向在二次频率转换的三倍频晶体内部共线或同步得更好。
  5. 如权利要求4所述的激光辐射三倍率产生的装置，其特征在于，所述补偿模块包括但不限于，采用以下形式之一：
    (1)一块或多块晶体的组合；
    (2)一个或多个普通棱镜或布鲁斯特角度的棱镜；
    (3)一个或多个具有延迟反射的啁啾镜；
    (4)一个或多个透镜或反射镜的组合。
  6. 如权利要求1所述的激光辐射三倍率产生的装置，其特征在于，所述前部光学系统包括部分或全部的：过渡介质、二倍频晶体和补偿模块，其中，
    所述过渡介质的至少一个界面切割为布鲁斯特入射角界面，用于对输入的基波光束的光强分布进行调整，出射到所述二倍频晶体上；
    所述二倍频晶体将由所述过渡介质调整后的基波部分地转换为二倍频谐波和剩余的基波，将剩余的基波和二倍频谐波出射至所述补偿模块或直接到三倍频晶体；
    所述补偿模块接收所述基波和二倍频谐波的入射，对所述基波和二倍频谐波实现空间上的走离角或时间上的脉冲延迟走离错开的预先补偿。
  7. 如权利要求6所述的激光辐射三倍率产生的装置，其特征在于，所述过渡介质具有至少一个界面为布鲁斯特角度切割，对入射的光束横截面光斑形状进行调整，使得所调整的基波光束具有有利于产生所需要的输出光束最终光斑形状的、和频转换所需的、二次谐波光束和剩余基波光束。
  8. 如权利要求1所述的激光辐射三倍率产生的装置，其特征在于，所述前部光学系统包括：二倍频晶体、过渡介质，其中，
    所述二倍频晶体将入射的基波光束转换为基波和二倍频谐波；
    所述过渡介质的入射面切割为布鲁斯特入射角界面，对产生的基波和二倍频谐波的光强分布进行调整。
  9. 如权利要求1所述的激光辐射三倍率产生的装置，其特征在于，所述前部光学系统包括：三倍频晶体、二倍频晶体和光学反射部件，所述三倍频晶体的一个界面切割为布鲁斯特角界面，兼作为所述基波光束第一次的入射面，其中，
    所述基波光束入射至所述三倍频晶体的布鲁斯特角界面，对输入的基波光束的横截面光强分布进行调整，出射至所述二倍频晶体；
    所述二倍频晶体将由所述三倍频晶体调整的基波转换为二倍频谐波，将剩余的基波和二倍频谐波出射至所述光学反射部件；
    所述光学反射部件将所述基波和二倍频谐波反射转折后，再次进入所述二倍频晶体，由所述二倍频晶体再次通过时进行二倍频转换以产生二倍频谐波，将剩余的基波和二倍频谐波出射至所述三倍频晶体；
    由所述三倍频晶体将输入的所述基波和二倍频谐波在所述三倍频晶体内发生和频转换，产生三倍频谐波，所述三倍频谐波经过所述三倍频晶体的布鲁斯特角界面后出射，矫正为与初始输入的基波光束的横截面光强分布形状 基本一致或所需形状的三倍频出射光束。
  10. 如权利要求1所述的激光辐射三倍率产生的装置，其特征在于，所述光学反射部件采用以下形式之一：
    (1)反射镜面；
    (2)一组多个反射镜面组成的集合部件；
    (3)一个锥形反射镜；
    (4)一个相位共轭反射镜片。
PCT/CN2020/085824 2019-07-26 2020-04-21 激光辐射三倍率产生的装置 WO2021017539A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201910684187.4A CN110286542A (zh) 2019-07-26 2019-07-26 激光辐射三倍率产生的装置
CN201910684187.4 2019-07-26

Publications (1)

Publication Number Publication Date
WO2021017539A1 true WO2021017539A1 (zh) 2021-02-04

Family

ID=68022803

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2020/085824 WO2021017539A1 (zh) 2019-07-26 2020-04-21 激光辐射三倍率产生的装置

Country Status (2)

Country Link
CN (1) CN110286542A (zh)
WO (1) WO2021017539A1 (zh)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116698375A (zh) * 2023-08-02 2023-09-05 中国工程物理研究院激光聚变研究中心 一种全激光功率段谐波转换效率曲线的获取方法

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110286542A (zh) * 2019-07-26 2019-09-27 南京钻石激光科技有限公司 激光辐射三倍率产生的装置
CN113708200A (zh) * 2020-06-18 2021-11-26 北京科益虹源光电技术有限公司 一种266nm深紫外激光发生装置
CN111880299B (zh) * 2020-06-22 2022-08-02 中国科学院苏州生物医学工程技术研究所 一种基于位相共轭反射镜的大视场数字扫描光片照明系统
CN112421361A (zh) * 2020-11-26 2021-02-26 中国林业科学研究院木材工业研究所 一种用于木材加工的紫外超快激光器

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5850407A (en) * 1997-11-25 1998-12-15 Lightwave Electronics Corporation Third-harmonic generator with uncoated brewster-cut dispersive output facet
CN101103501A (zh) * 2004-11-30 2008-01-09 电子科学工业公司 用于耐久高功率激光波长变换的非线性晶体改进
JP5159815B2 (ja) * 2010-03-19 2013-03-13 三菱電機株式会社 波長変換レーザ装置
CN105210245A (zh) * 2013-03-14 2015-12-30 Ipg光子公司 具有圆形输出光束的高效单通型谐波发生器
CN106410583A (zh) * 2016-06-17 2017-02-15 北京国科世纪激光技术有限公司 腔内倍频增强型激光器
CN206022873U (zh) * 2016-08-29 2017-03-15 福州紫凤光电科技有限公司 一种离散角补偿三倍频紫外激光器
CN110286542A (zh) * 2019-07-26 2019-09-27 南京钻石激光科技有限公司 激光辐射三倍率产生的装置

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6697391B2 (en) * 2002-03-28 2004-02-24 Lightwave Electronics Intracavity resonantly enhanced fourth-harmonic generation using uncoated brewster surfaces
CN1162945C (zh) * 2002-08-13 2004-08-18 深圳市大族激光科技股份有限公司 一种三次谐波激光产生方法
JP4636020B2 (ja) * 2004-05-26 2011-02-23 株式会社ニコン 波長変換光学系、レーザ光源、露光装置、マスク検査装置、及び高分子結晶の加工装置
CN100499297C (zh) * 2006-07-31 2009-06-10 深圳市大族激光科技股份有限公司 三次谐波激光的产生方法
US9709873B2 (en) * 2013-12-19 2017-07-18 Danmarks Tekniske Universitet Laser apparatus with cascade of nonlinear frequency mixers
CN208707065U (zh) * 2018-08-06 2019-04-05 福建科彤光电技术有限公司 一种紫外激光倍频器
CN208797344U (zh) * 2018-08-13 2019-04-26 苏州帕沃激光科技有限公司 一种磁驱悬浮颗粒紫外激光器
CN210465939U (zh) * 2019-07-26 2020-05-05 南京钻石激光科技有限公司 激光辐射三倍率产生的装置

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5850407A (en) * 1997-11-25 1998-12-15 Lightwave Electronics Corporation Third-harmonic generator with uncoated brewster-cut dispersive output facet
CN101103501A (zh) * 2004-11-30 2008-01-09 电子科学工业公司 用于耐久高功率激光波长变换的非线性晶体改进
JP5159815B2 (ja) * 2010-03-19 2013-03-13 三菱電機株式会社 波長変換レーザ装置
CN105210245A (zh) * 2013-03-14 2015-12-30 Ipg光子公司 具有圆形输出光束的高效单通型谐波发生器
CN106410583A (zh) * 2016-06-17 2017-02-15 北京国科世纪激光技术有限公司 腔内倍频增强型激光器
CN206022873U (zh) * 2016-08-29 2017-03-15 福州紫凤光电科技有限公司 一种离散角补偿三倍频紫外激光器
CN110286542A (zh) * 2019-07-26 2019-09-27 南京钻石激光科技有限公司 激光辐射三倍率产生的装置

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116698375A (zh) * 2023-08-02 2023-09-05 中国工程物理研究院激光聚变研究中心 一种全激光功率段谐波转换效率曲线的获取方法
CN116698375B (zh) * 2023-08-02 2023-10-17 中国工程物理研究院激光聚变研究中心 一种全激光功率段谐波转换效率曲线的获取方法

Also Published As

Publication number Publication date
CN110286542A (zh) 2019-09-27

Similar Documents

Publication Publication Date Title
WO2021017539A1 (zh) 激光辐射三倍率产生的装置
US5909456A (en) Laser beam generator
KR102344775B1 (ko) 제3 고조파 생성을 위한 고효율 레이저 시스템
JP6478804B2 (ja) カスケード光高調波発生
US11796889B2 (en) Frequency conversion arrangement for optimising properties of a harmonic of a laser
CN111106521A (zh) 一种和频装置和激光器
CN210465939U (zh) 激光辐射三倍率产生的装置
US9425581B2 (en) Anisotropic beam pumping of a Kerr lens modelocked laser
CN110556699B (zh) 纳秒激光器泵浦的高能量高光束质量可调谐光参量振荡器
CN210379758U (zh) 一种声光调q紫外激光器
CN110277726B (zh) 一种声光调q紫外激光器
US9568803B2 (en) Cascaded optical harmonic generation
CN108107642B (zh) 一种固体和频钠导星光谱连续激光输出装置及输出方法
CN101345389A (zh) 全固态五波长同时输出的激光装置及五波长激光产生方法
CN107465104A (zh) 一种电光调q的角锥谐振腔
CN114649728A (zh) 一种飞秒三倍频脉冲激光发生装置及方法
CN217789031U (zh) 一种激光装置
US20130208741A1 (en) Laser architectures
CN218275499U (zh) 高功率纳秒腔外五倍频激光器
CN112490836B (zh) 一种基于环形非稳腔的气体拉曼激光器
EP3255489B1 (en) Cascaded optical harmonic generation
CN108051973B (zh) 一种固体和频钠导星放大自发辐射光源及和频光输出方法
CN115084980A (zh) 高功率纳秒腔外五倍频激光器
CN116826494A (zh) 一种基于组合晶体的双波长涡旋激光器
CN110676682A (zh) 一种用于提高三次谐波产生效率的激光设备

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20848477

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 20848477

Country of ref document: EP

Kind code of ref document: A1

122 Ep: pct application non-entry in european phase

Ref document number: 20848477

Country of ref document: EP

Kind code of ref document: A1

122 Ep: pct application non-entry in european phase

Ref document number: 20848477

Country of ref document: EP

Kind code of ref document: A1

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 112(1) EPC (EPO FORM 1205A DATED 14/11/2022)

122 Ep: pct application non-entry in european phase

Ref document number: 20848477

Country of ref document: EP

Kind code of ref document: A1