CN105428980A - Design method of end-pumped resistance-trimming laser - Google Patents
Design method of end-pumped resistance-trimming laser Download PDFInfo
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- CN105428980A CN105428980A CN201511025191.8A CN201511025191A CN105428980A CN 105428980 A CN105428980 A CN 105428980A CN 201511025191 A CN201511025191 A CN 201511025191A CN 105428980 A CN105428980 A CN 105428980A
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- resistance trimming
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
- H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
- H01S3/094038—End pumping
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
- H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
- H01S3/094049—Guiding of the pump light
- H01S3/094053—Fibre coupled pump, e.g. delivering pump light using a fibre or a fibre bundle
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- Electromagnetism (AREA)
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- Plasma & Fusion (AREA)
- Optics & Photonics (AREA)
- Lasers (AREA)
Abstract
The invention belongs to the laser technical field and relates to a design method of an end-pumped resistance-trimming laser. The design method of the invention includes the following steps of: S1, pulse width control: the optical path length of the optical cavity of the laser is designed to 350mm; S2, optical fiber coupling module selection: laser upper-energy level particle number layout is provided; S3, optical fiber coupling: 1:1 imaging is adopted to make imaging performed in a Nd:YAG crystal, so that pumping can be carried out; S4, laser crystal selection: a single-ended bonding Nd:YAG crystal is adopted, and the bonding surface of the Nd:YAG crystal is a pumping light incident surface; and S5, the design of an optical resonant cavity: the front cavity mirror and the rear cavity mirror of the optical resonant cavity are of convex mirror structures. According to the design method of the end-pumped resistance-trimming laser of the invention, optical design schemes are set, and the bonding crystal is adopted, and therefore, end-surface thermal effects can be decreased, and the quality of light beams can be improved.
Description
Technical field
The present invention relates to field of laser device technology, particularly a kind of method for designing of end pumping resistance trimming laser.
Background technology
Thin film circuit widely uses in electronic equipment, and most basic element in this electronic equipment, plays vital effect to the popularization of electronic circuit.Control to be actually the basis realizing fine Electronic processing to the resistance of thin film circuit, and laser resistance adjuster exactly can realize the accurate control to resistance in thin film circuit.
Resistance trimming laser can pass through short-pulse laser scan incision resistance substrate, make resistance slurry layer Stimulated Light heating and gasifying, form the cut of certain depth, thus change the conductive section sum conductive lengths of resistive element, reach and the resistance lower than target resistance is trimmed in the deviation range that resistance allows.
The design of resistance trimming laser is widely used in thin, thick film hybrid integrated circuit, electronic devices and components, car electrics, transducer, the application of plate resistor.
Summary of the invention
The present invention is intended to the defect overcoming prior art, provides a kind of method for designing of end pumping resistance trimming laser.
For achieving the above object, the present invention is by the following technical solutions:
S1, pulse width control: the optical path length of design laser optical cavity is 350mm; S2, fiber coupling module are chosen: provide upper laser level population layout; S3, coupling fiber part: adopt 1:1 to be imaged onto Nd:YAG crystal and carry out pumping; S4, laser crystal are chosen: the Nd:YAG crystal adopting a single-ended bonding, and bonding face is pump beam incidence surface; The design of S5, optical resonator; Former and later two chamber mirrors are adopted to be the structure of convex mirror.
In some embodiments, in step S1, the centre position of laser optical cavity arranges mirror of turning back.
In some embodiments, described fiber coupling module is chosen to comprise further and is adopted relevant FAP800-40W fiber coupling module.
In some embodiments, described fiber coupling module is SMA head; Pump wavelength is 808nm.
In some embodiments, described laser crystal Selecting All Parameters is length 2+18 (mm), diameter of phi 2mm, concentration 0.4%.
In some embodiments, the curvature of described two convex mirrors is R=-5000mm, and wherein, described two convex mirror one is speculum, and another is the outgoing mirror of T=20%.
Beneficial effect of the present invention is: by arranging optical design scheme, uses bonded crystals, reduces end face thermal effect and improves beam quality.
Accompanying drawing explanation
Fig. 1 changes schematic diagram for laser facula radius according to the present invention with thermal focal.
Embodiment
In order to make object of the present invention, technical scheme and advantage clearly understand, below in conjunction with drawings and the specific embodiments, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, and be not construed as limiting the invention.
Shown in composition graphs 1, the invention provides a kind of method for designing of end pumping resistance trimming laser, comprising:
S1, pulse width control: laser design of the present invention requires that bright dipping pulsewidth is 35ns10kHz for when peak power 8W, and the optical path length adopting design optics cavity is 350mm.
Due to acousto-optic Q crystal, Nd:YAG crystal etc. in optics cavity, actual geometric distance is shorter than optical path length, and its geometric distance is 316mm.
Because overall light path is long, further, the centre position of laser optical cavity arranges mirror of turning back, thus laser is done compacter.
S2, fiber coupling module are chosen: provide upper laser level population layout, thus produce the laser of transition.
Normally used fiber coupling module is the fiber coupling module of Dilas, but it has long optical fiber pigtail usually, and when optical fiber pigtail is shorter than 10m, shake optical fiber has considerable influence to laser power.For improving power stability, reduce the impact that optical fiber pigtail produces power fluctuation, relevant FAP800-40W module is selected in design, and this fiber coupling module optical fiber is SMA head; Pump wavelength is 808nm, does not have the impact of optical fiber pigtail on power.
S3, coupling fiber part: adopt 1:1 to be imaged onto Nd:YAG crystal and carry out pumping.
Wherein, the wire core diameter of relevant FAP800-40W module is 800um, and the ideal image be imaged onto in Nd:YAG crystal is 800um, and owing to having the situations such as astigmatism, imaging facula is slightly larger than desirable hot spot.Now, pump light hot spot is also allow basic mode carry out starting of oscillation slightly larger than laser facula, suppresses the generation of high-rder mode.
S4, laser crystal are chosen:
Wherein, laser crystal is lasing carrier, and the pumping of ground state particle to excitation state, is produced laser by stimulated radiation transition by absorption of crystal pump light.Laser crystal due to quantum defect effect, makes a part of pump energy be converted into heat in the lasing process of absorptive pumping light.When laser normally works time, there is certain temperature gradient in laser crystal, due to temperature gradient existence thus create thermal lensing effect.Under the design of laser of the present invention makes laser stabilization be operated in different pumping by the design of lumen type.For the difference of laser crystal pump mode, laser can be divided into side pump and end pump, and the optical quality of usual end-pumped laser can be more excellent.
End-pumped laser injects very high energy in the one or both sides of laser crystal, and due to the absorption of crystal, the radial direction in laser crystal inside is all different with tangential direction Temperature Distribution, thus can produce effect of end surface, is equivalent to plane rod end face shape and changes; Effect of end surface is equivalent to primary plane face type to become parabola, thus produces huge astigmatism to hot spot.
For solving effect of end surface, at the base material of the crystal front end face bonding active ions that do not adulterate.Be the laser of design high light beam quality, selection laser crystal is the Nd:YAG crystal of a single-ended bonding, and bonding face is pump beam incidence surface simultaneously.
Adopt bonded crystals, solve the heat dissipation problem of pumping end surface, reduce effect of end surface and stress effect; Reduce overall thermal focal, improve overall laser light power.
Wherein, this laser crystal parameter is YAG+Nd:YAG, length 2+18 (mm), diameter of phi 2mm, concentration 0.4%.The diameter of this laser crystal is Φ 2mm, on the one hand, crystal aperture is produced from aperture limit mould, can partly filter high-order film; On the other hand, little diameter is more conducive to the heat radiation of laser crystal.
The design of S5, optical resonator: adopt former and later two chamber mirrors to be the structure of convex mirror.
Chamber due to entirety is long long, for increasing corresponding Fresnel scattering process, improves peak power, laser crystal is positioned over the centre position of laser cavity, laser crystal pumping can be made to enter more power, reach less thermal focal, thus make laser reach the object of high power running.
Because laser of the present invention is high light beam quality laser, theoretical according to fresnel diffraction, only have when chamber mirror is convex mirror time, the diffraction effect produced the high-rder mode beyond TEM00 mould is maximum, adopts former and later two chamber mirrors to be the structure of convex mirror.
Wherein, the curvature of two convex mirrors is R=-5000mm, and one of them is speculum, and another is the outgoing mirror of T=20%.
When Effect of Back-Cavity Mirror and output coupling mirror are all convex mirror, the operation interval of laser is not linear.Another of laser of the present invention requires as linear work, take into account low-power resistance trimming and high power resistance trimming works simultaneously, so this kind of laser employs a kind of method increasing laser threshold make laser namely in the work of unsteady cavity internal linear, extraordinary model selection function can be had again.
Be specially, laser transverse mode meets two distribution equations in optics cavity, is respectively Hermite-Gaussian and Laguerre Gauss.Produce the difference that the different reason of above-mentioned two kinds of Gaussian form is diffactive lens plate shape, the equation describing laser transverse mode distribution is expression way difference, can be similar to think that two kinds of forms are consistent when calculating laser high-rder mode spot diameter.
High light beam quality laser is want the hot spot of laser emitting to be fundamental transverse mode TEM00 mould, and when desirable TEM00 mould time, beam quality is M
2=1, when high-power operation time, have some high-rder modes and exist, these high-rder modes can occupy certain component in this laser power, when component value is too high time, and optical quality severe exacerbation.
Under normal circumstances, M is worked as
2be basic mode laser during <1.5, make a M
2the laser of <1.1 compares M
2the laser harshness of=1.5 is many.Now, there is provided beam quality will limit vibrating in mode except TEM00, when calculating with Hermite-Gaussian, the higher order mode of single order larger than TEM00 mould is TEM01 (or TEM10), and the spot radius of TEM01 is TEM00 spot radius
doubly.
Wherein, formula 1 is multimode light distribution formula, and formula 2 is the transmissivity formula after increasing diaphragm.High light beam quality laser can place diaphragm in laser cavity, and basic mode laser is passed through with less energy loss, and allows high-rder mode laser lose with larger energy loss, namely less numerical aperture can increase the beam quality of laser.Above needing application when designing diaphragm size, two formula calculate.
For basic mode laser, usually only consider that TEM01 mould is on the impact of basic mode, as long as increase the loss of TEM01 mould, high-rder mode just can not starting of oscillation.Selecting hole position size is 1.5 times of basic mode light beam herein, can increase the transmitance of basic mode so as far as possible, and reduce the transmitance of high-rder mode.
When diaphragm is basic mode 1.5 times, the one way transmitance of basic mode is 99.5% according to formula 2, then corresponding after periodic duty cavity loss is 1%, and this loss can produce Laser output, but reduces maximum power.
When diaphragm is basic mode 1.5 times, the one way transmitance of TEM01 mould is 71% according to formula 2, then corresponding after periodic duty cavity loss is 50.4%, is now high energy loss, when pump power is lower time, and TEM01 not starting of oscillation substantially substantially; When pump power is very high, has less TEM01 power in laser power and carry out starting of oscillation, as long as ensure that the proportion in aggregate power range shared by TEM01 is very little, beam quality factor M can be made
2close to 1.
The like, when diaphragm is basic mode 1.5 times, TEM11 mould is more difficult to starting of oscillation.Place two Φ 0.9 diaphragms in front Effect of Back-Cavity Mirror position in the present invention, better beam quality can be reached.The cavity loss increasing laser is actually after increasing diaphragm, because cavity effects is biconvex unsteady cavity, this laser just can not carry out work in a linear fashion, and increase the senior mould that namely aperture has filtered laser, turn increase the operation threshold of laser, when within the scope of the steady district that laser work threshold value just falls laser works time, laser just can linear work.
As shown in Figure 1, for laser facula radius changes schematic diagram with thermal focal, arrow locations is increase the threshold position after aperture, as can be seen from the figure from threshold value to maximum value position, laser can linear work.
Except increase aperture can improve except beam quality, also has a method improving beam quality for place polarizer in the optical path.Think to only have two pattern-TEM00 and TEM01 when placing the light after aperture in laser cavity, wherein the polarization state of TEM01 is just in time contrary with the polarization state of TEM00, in laser cavity, place polarizer can distinguish two polarization states, beam quality can be improved further.
The present invention improves the method for the beam quality of laser from multiple angle, and one, use bonded crystals, reduce end face thermal effect and improve beam quality; Two, the crystal bar of Φ 2mm is used to carry out from aperture modeling; Three, use in the both sides of chamber mirror two convex mirrors to carry out diffraction modeling and improve beam quality; Four, increase by two apertures and filter senior mould; Five, place polarizer in chamber, by the mode of polarization, basic mode is screened.By multiple effective optical instrument, beam quality is controlled to M when 8W10kHz
2<1.1, has reached very high beam quality.This external 5W power M once
2<1.05, substantially close to the basic mode limit.
The raising of stability.The raising of laser stability mainly controls the temperature with temperature control point, the place in the design with temperature controlling point is fiber coupling module and Nd:YAG crystal, so use TEC to add the combination of thermistor for accurately controlling the temperature of respective point in the position of key point, wherein temperature control precision is 0.2 DEG C, can ensure overall power short-term stability like this.The stability of laser, except wanting control temperature, also needs the deformation quantity controlling whole cavity, and the cavity of use needs to carry out actual effect process fully, can ensure the long-time stability of overall power like this; In addition all stand for optical lens are adopted as stainless steel structure, also can ensure the long-time stability of optics.
Gao Zhongying scope: the present invention adopts 41M acousto-optic Q to open the light, in conjunction with the performance of Nd:YAG crystal, overall repetition scope is 1kHz ~ 30kHz, and high repetition can improve process velocity.
Body laser design of the present invention can design and can meet the use of high accuracy resistance trimming, this laser: one, beam quality (the low-power M of superelevation
2≈ 1, high power <1.1); Two, light power linear work (0W ~ 8W continuously adjustabe); Three, high power stability (overall power stability RMS<0.5%, pulse stability PP<3%); Four, Gao Zhongying work (1kHz ~ 30kHz).
The present invention is catch light beam quality, high impulse stability, Gao Zhongying scope, linear tunable resistance trimming laser.This laser design adopts end pumping Nd:YAG crystal, and utilize acousto-optic Q modulation principle to produce Gao Zhongying, pulsewidth 35ns can produce enough heats and gasify, and working region is linearly tunable from threshold value simultaneously, and light power is 8W10kHz.
In optical design, high optical quality and the highest light power are conflicting things, need to do one between and accept or reject and balance, and this kind of laser still can arrive beam quality M under peak power
2the result of <1.1, when power is low, beam quality is close to 1, and this is high light beam quality design result.
Both increase TEC temperature regulating device in the position of all temperature influences on engineering, make laser works in stable temperature, reduce environment to the impact of Primary Component temperature drift.
The above the specific embodiment of the present invention, does not form limiting the scope of the present invention.Any various other done by technical conceive of the present invention change and distortion accordingly, all should be included in the protection range of the claims in the present invention.
Claims (7)
1. a method for designing for end pumping resistance trimming laser, is characterized in that, comprising:
S1, pulse width control: the optical path length of design laser optical cavity is 350mm;
S2, fiber coupling module are chosen: provide upper laser level population layout;
S3, coupling fiber part: adopt 1:1 to be imaged onto Nd:YAG crystal and carry out pumping;
S4, laser crystal are chosen: the Nd:YAG crystal adopting a single-ended bonding, and bonding face is pump beam incidence surface;
The design of S5, optical resonator: adopt former and later two chamber mirrors to be the structure of convex mirror.
2. the method for designing of a kind of end pumping resistance trimming laser as claimed in claim 1, is characterized in that, in step S1, the centre position of laser optical cavity arranges mirror of turning back.
3. the method for designing of a kind of end pumping resistance trimming laser as claimed in claim 1, is characterized in that, described fiber coupling module is chosen to comprise further and adopted relevant FAP800-40W fiber coupling module.
4. the method for designing of a kind of end pumping resistance trimming laser as claimed in claim 3, it is characterized in that, described fiber coupling module is SMA head; Pump wavelength is 808nm.
5. the method for designing of a kind of end pumping resistance trimming laser as claimed in claim 1, is characterized in that, described laser crystal Selecting All Parameters is length 2+18 (mm), diameter of phi 2mm, concentration 0.4%.
6. the method for designing of a kind of end pumping resistance trimming laser as claimed in claim 1, is characterized in that, the curvature of described two convex mirrors is R=-5000mm, and wherein, described two convex mirror one is speculum, and another is the outgoing mirror of T=20%.
7. the method for designing of a kind of end pumping resistance trimming laser as claimed in claim 1, is characterized in that, two Φ 0.9 diaphragms placed respectively by former and later two chamber mirrors described.
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| CN201511025191.8A CN105428980A (en) | 2015-12-30 | 2015-12-30 | Design method of end-pumped resistance-trimming laser |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1069360A (en) * | 1991-08-15 | 1993-02-24 | 中国科学院上海光学精密机械研究所 | Multifunctional laser resistance trimming machine |
| CN1317856A (en) * | 2001-02-09 | 2001-10-17 | 周寿桓 | Excited coupling resonance-cavity laser |
| US20030118073A1 (en) * | 2001-12-21 | 2003-06-26 | Fsona Communications Corporation | Compact optical amplifier, a system incorporating the same, and an optical amplification method |
| CN1645691A (en) * | 2005-02-02 | 2005-07-27 | 中国科学院物理研究所 | Active and passive Q-adjusted single longitudinal mode laser |
| US20080082089A1 (en) * | 2006-09-29 | 2008-04-03 | Candela Corporation | Treatment of Skin by a Solid-State Laser |
| CN102544988A (en) * | 2011-02-25 | 2012-07-04 | 北京国科世纪激光技术有限公司 | Laser cavity mirror clamping mechanism, laser resonant cavity and laser |
| CN104158082A (en) * | 2014-09-03 | 2014-11-19 | 四川卓众科技有限公司 | Method and solid laser device for outputting macro-energy single longitudinal mode short-pulse lasers |
-
2015
- 2015-12-30 CN CN201511025191.8A patent/CN105428980A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1069360A (en) * | 1991-08-15 | 1993-02-24 | 中国科学院上海光学精密机械研究所 | Multifunctional laser resistance trimming machine |
| CN1317856A (en) * | 2001-02-09 | 2001-10-17 | 周寿桓 | Excited coupling resonance-cavity laser |
| US20030118073A1 (en) * | 2001-12-21 | 2003-06-26 | Fsona Communications Corporation | Compact optical amplifier, a system incorporating the same, and an optical amplification method |
| CN1645691A (en) * | 2005-02-02 | 2005-07-27 | 中国科学院物理研究所 | Active and passive Q-adjusted single longitudinal mode laser |
| US20080082089A1 (en) * | 2006-09-29 | 2008-04-03 | Candela Corporation | Treatment of Skin by a Solid-State Laser |
| CN102544988A (en) * | 2011-02-25 | 2012-07-04 | 北京国科世纪激光技术有限公司 | Laser cavity mirror clamping mechanism, laser resonant cavity and laser |
| CN104158082A (en) * | 2014-09-03 | 2014-11-19 | 四川卓众科技有限公司 | Method and solid laser device for outputting macro-energy single longitudinal mode short-pulse lasers |
Non-Patent Citations (1)
| Title |
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| W.克希耐尔 著: "《固体激光工程》", 31 May 2001 * |
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