CN1140945C - Non-resonance cavity light parametric oscillator - Google Patents

Abstract

The present invention provides a non-resonance cavity type light parameter oscillator which is composed of a light splitting mirror, an input mirror, two crystals and a rotary table, wherein the input mirror is arranged behind the light splitting mirror, the two crystals and an output mirror are arranged behind the input mirror in sequence, and the crystals are put on the rotary table. Tunable lasers with single wavelengths are respectively output in front and back directions of the present invention; the positions of two cavity mirrors are exchanged to exchange output wavelengths, and the tuning range is large. The present invention has wide application prospects.

Description

Non-resonance cavity light parametric oscillator

The present invention proposes a kind of non-resonance cavity light parametric oscillator.

Optical parametric oscillator (OPO) can produce from ultraviolet to the far infrared coherent radiation as a kind of important tunable wave length LASER Light Source.Have purposes widely, be applied to differential absorption lidar atmospheric sounding pollutant levels on civilian, natural gas and petroleum pipeline leak detection, relevant contactless Flame Temperature Distribution of anti-Stokes and gas componant are measured; Can be used as analysis, the diagnostic instrments of research fields such as laser spectroscopy, laser life science in addition.Optical parametric oscillator is according to nonlinear optics difference frequency principle, and by a branch of light laser irradiation nonlinear crystal, the radiant light that produces two wavelength in the crystal comes and goes the vibration back and forms laser output in resonant cavity.OPO is by the crystal corner or regulate crystal temperature effect and realize wavelength tuning, and whether easy to use how to design tuning system becomes wavelength control precision and major issue.Usually the resonant cavity outgoing mirror is 50%-90% to the reflectivity of resonance wave, and two wavelength lasers of the length of output (ideler frequency ripple and signal wave) need to filter one of them wavelength in use.The method that filters can be added polarization splitting prism and total reflection diaphragm behind outgoing mirror, need a few cover diaphragms to change when wide-band tuning, can increase the complexity of cost and use like this.

Purpose of the present invention is done paired shortwave respectively with two chamber sheets of OPO resonant cavity and is all-trans and long wave is all-trans according to the mutual transfer characteristic of nonlinear optics frequency, thereby has exempted the outgoing mirror of 50%-90% reflectivity.

Structure of the present invention is: in the back of spectroscope 1 input mirror 2 is housed, input mirror 2 left sides are coated with the anti-reflection film at the pump light wavelength, the relatively short wavelength film that is all-trans in two kinds of wavelength in the right-hand member of the input mirror 2 plating oscillator, by front and back first crystal 4 and second crystal 5 are housed in proper order in input mirror 2 back, first crystal 4 and second crystal 5 keep sustained height, first crystal 4 and second crystal 5 are placed on first turntable 6 respectively, on second turntable 7, in the second crystal 5 back outgoing mirror 3 is housed, first crystal 4 and the second crystal 5 reverse rotation, rubber friction wheel 8 left ends are enclosed within on first turntable 6, the right-hand member of rubber friction wheel 8 is enclosed within on second turntable 7, the relatively long wavelength film that is all-trans in two kinds of wavelength in the outgoing mirror 3 left ends platings oscillator, first crystal 4 and second crystal 5 are nonlinear optical crystal.Its operation principle is: flashlight and ideler frequency light resonance not in the chamber, replacement be that the energy of signal light field and ideler frequency light field exchanges mutually the feedback that was provided by output coupling mirror originally is provided in the chamber.The parameteric light of two wavelength all has higher transmission loss, thereby flashlight and the ideler frequency Bob value to pumping wave is very little again with frequently, two light wave amplitudes that same direction is propagated in the chamber differ bigger, a little less than the competition between the mould of chamber, thereby efficient will be higher than the input and output mirror simultaneously to two double resonance optical parametric oscillators that the parameteric light wave height is anti-with stability.The single flashlight of its output or ideler frequency light energy will be higher than the energy of other coupling output.Running of the present invention is as follows: input mirror of the present invention and outgoing mirror constitute a laserresonator, produce the laser of two wavelength in this resonant cavity, and wherein input mirror is all-trans to short-wave laser, and outgoing mirror is all-trans to long wave laser.After forming stable oscillation stationary vibration, short-wave laser is exported from outgoing mirror, and long wave laser is output mirroring and exports from input mirror.Yttrium neodymium garnet laser produces a branch of wavelength 532nm laser and reflexes in the resonant cavity through one 45 ° of spectroscopes, input mirror 2 left sides platings 532nm anti-reflection film, the right side plating shortwave film that is all-trans, and bandwidth range is 0.76-0.88 μ m.The transmissivity of 2 couples of 532nm of input mirror surpasses 98%, thereby most of energy enters and participate in pumping in the resonant cavity, helps the raising of conversion efficiency.Outgoing mirror also is the two sides plated film, and wherein be all-trans to long wave 1.35-1.57 μ m in the left side, to the transmissivity of short wavelength's signal wave greater than 80%; The right side plating 532nm film (reflectivity is greater than 99%) that is all-trans, one of them effect is the filtering pump light, another effect is that backward pumping produces the backhaul gain.For effectively reducing the starting of oscillation threshold value of resonant cavity, place the ktp crystal of two end face plating anti-reflection films in the resonant cavity, the crystallographic axis of two crystal is positioned at the resonator axis both sides, reverse rotation separately in the tuning process, the beam direction that compensation causes owing to the crystal corner departs from.Bicrystal has not only increased actual gain length, but also has reduced the requirement to the pump light beam quality.The angle of pumping light and chamber axle is 1-5 °, and the purpose of doing like this is that the back reflected laser that prevents each minute surface and crystal end-face enters in the pump laser, damages optical element.The crystal turntable drives mutually by rubber hoop mill sassafras, and one of them turntable is by step motor drive.1.8 ° of stepping motor step angles, each step is by 8 segmentations in motor drive circuit; Decelerator adopts the turbine worm structure, and speed reducing ratio is 200: 1.The real crystal turret systems rotates a week, and need send umber of pulse to stepping motor is 320000, and it is 0.0011 ° that per step of turntable rotates, and is equivalent to 4 rads.Stepping motor is walked to move a step, the wavelength change 0.15cm of resonant cavity output ^-1

Advantage of the present invention: 1. front and back are to the tunable laser of exporting single wavelength respectively, and two chamber mirror location swaps then output wavelength exchange.2. tuning range is big, short-wave laser tuning range 0.698-1.026 μ m (forward direction output, the long dotted line of ash is represented), long wave laser tunable range 1.105-2.23 μ m (output backward, grey short dash line is represented).3. owing to its low-loss, high gain characteristics, a cover diaphragm can realize that all band is tuning.

Fig. 1 is a principle of the invention structure chart.

Embodiment:

30 millimeters in spectroscope of the present invention, input mirror, outgoing mirror diameter, 3 millimeters of thickness.Crystalline size is 10 * 12 * 15mm ³, the crystal main shaft is positioned at the x-z plane, with the angle of logical optical axis be 62.7 °.

Claims (1)

1, a kind of non-resonance cavity light parametric oscillator, it is characterized in that: mainly by spectroscope [1], input mirror [2], outgoing mirror [3] and first crystal [4], second crystal [5] and first turntable [6], second turntable [7] is formed, wherein input mirror [2] is housed in the back of spectroscope [1], input mirror [2] left side is coated with the anti-reflection film at the pump light wavelength, the relatively short wavelength film that is all-trans in two kinds of wavelength in the right-hand member of input mirror [2] the plating oscillator, by front and back first crystal [4] and second crystal [5] are housed in proper order in input mirror [2] back, first crystal [4] and second crystal [5] keep sustained height, first crystal [4] and second crystal [5] are placed on first turntable [6] respectively, on second turntable [7], in second crystal [5] back outgoing mirror [3] is housed, first crystal [4] and second crystal [5] reverse rotation, rubber friction wheel [8] left end is enclosed within on first turntable [6], the right-hand member of rubber friction wheel [8] is enclosed within on second turntable [7], the relatively long wavelength film that is all-trans in two kinds of wavelength in outgoing mirror [3] the left end plating oscillator, first crystal [4] and second crystal [5] are nonlinear optical crystal.

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