CN1421966A - 1.3mum waveband superpulse Nd-doped crystal laser - Google Patents

Abstract

The 1.3 micron band superpulse Nd-doped crystal laser has one of the laser crystals Nd:YAG, Nd:YVO4, Nd:YAP, Nd:YLF and Nd:BEL as laser activated medium; Kr lamp, and Xe lamp or diode laser as pump source. In pulse operation mode, the device outputs 1.3 micron band superpulse fundamental wave or coherent radiation produced by the optical frequency variable crystal set inside or outside the cavity. Inside the resonant cavity, is inserted acousto-optical modulator or electro-optical modulator assemblb with clipping effect and 5-20 KHz modulation. The laser of the present invention can produce high-peak power pulse. Compared with available CO2 laser for orthopaedic purpose, the laser of the present invention may have ever sharp edge, less scar formed and less heat damage, and has ever wide clinical application foreground.

Description

1.3 the super pulse Nd-doped crystal laser of mu m waveband

The super pulse Nd-doped crystal laser of 1.3 mu m wavebands of the present invention belongs to optoelectronic areas.The coherent radiation of its first-harmonic and additive mixing thereof can be applicable to many aspects such as laser medicine, laser processing, laser communications, astronomy.

The super pulse laser of time integer refers to rising edge and a few Millisecond pulses at zero point of trailing edge steep (about μ s magnitude) variation or the laser of pulse envelope of time.At gas CO ₂The report of the super pulse of free integer is (referring to the super pulse CO of COHERENT high energy in the laser ₂Shaping laser---http://www.cohr.com); And in Solid State Laser, particularly do not see the super pulse report of time shaping as yet at 1.3 micron wavebands.

Gas CO ₂Super pulse laser is a kind of novel beauty treatment, the plastic surgery operations laser that comes out in the nineties latter stage, and it is one of the most high-tech crystallization in the present laser medicine field, is CO ₂Regeneration product in the laser.The cutting of conventional laser medical treatment machine is unfavorable, doctor's operating handle is bad because of having avoided, follow the fatal shortcoming of eschar on the otch of when injected organism tissue, and it has " laser scalpel " characteristic truly to a certain extent.Yet also there is fatal shortcoming in itself: the CO of 10.6 μ m ₂Laser can't be used optical fiber light-guiding, can't enter esophagus, tracheae, abdominal cavity etc. a large amount of in peep operation, thereby can only be confined to the operation of shallow table at present.

1.0 the laser hemostasis of mu m waveband is good, the cutting is poor, the laser of 10.6 mu m wavebands is poor to tissue well cutting, hemostasis, and the water in organizing is to the absorption coefficient of the 1.3 μ m CO between 10.6 μ m ₂Between the Nd:YAG laser of laser and 1.06 μ m, so 1.3 μ m are cutting at present and the best wave band that stops blooding and take into account.The 1.3414 μ m Nd:YAP continuous lasers medical treatment machine of available fiber leaded light has certain competitiveness and (reports referring to foreign progress on laser medicine, " 1.3 mum wavelength Nd:YAP lasers are expected to improve medical function ", laser and optoelectronics progress, 1998, the 6th phase, 40 pages).But discovery still has shortcoming from clinical, occurs eschar, the edge of a knife surface of a wound broad of certain limit during as cutting, can't do delicate procedure.Its quasi continuous operation mode also still is not enough to resist mutually with Ho:YAG laser.

Laser tissue experiment showed, and will make the body tissue instant vaporization, just must reach a critical power, energy scale.And traditional continuous or quasi-continuous lasing can only be under very low energy output level, and time that this just obviously very big delay is performed the operation just can reach this critical standard.The principle of laser cutting tissue is: contained moisture in the vaporization tissue.When the tissue that will be acted on when enough laser energies absorbs, it will be with intracellular moisture vaporization, and take away the smog of vaporization simultaneously, and the steam in the smog can siphon away most laser heat energy, remaining heat can make the active region surrounding tissue produce heat injury.Laser beam is a continuation to tissue heating, so the time more for a long time, to the thermal diffusion of surrounding tissue and cause the situation of heat injury more serious.If too much laser energy has been consumed in this heat conduction, or laser energy is when not enough, and laser is only at heat tissue gradually rather than make its vaporization immediately, and this slow thermalization phenomenon makes tissue drying up to coking, and can cause the fire damage of surrounding tissue.After eschar formed, laser energy will be sent to organized the needed time longer, and eschar can be heated surrounding tissue because of absorbing laser energy more.Therefore, the key point that reduce heat injury is to make the enough energy of each laser pulse output, and the destination organization of vaporizing immediately passes to tissue on every side thereby reduce heat.Thereby each laser pulse time is extremely short, promptly make the no time enough of heat be transmitted to surrounding tissue in less than the slow Henan of the heat time, and LASER HEAT only is vaporized smog and takes away.This new-type high-peak power short pulse technology promptly is super pulse (Ultrapulse).

The objective of the invention is to disclose a kind of can be with gas CO ₂" the super pulse solid laser of 1.3 micron wavebands of time shaping " that the advantage of super pulse laser and 1.3414 μ mNd:YAP continuous wave lasers organically combines, it can be used in the medical treatment in other words, can be little with optical fiber light-guiding, cutting no eschar, the edge of a knife surface of a wound, take into account hemostasis, then necessarily have application promise in clinical practice.

Realize that technical scheme of the present invention can be illustrated by accompanying drawing: Fig. 1 has provided super pulse laser and the comparison of quasi-continuous lasing on time response.The laser cavity structure that is adopted is seen Fig. 2, and we propose at Nd:YAG, Nd:YAP, Nd:YVO ₄, Nd:YLF these can produce and produce the super pulse of new time shaping that needs in 1.3 microns the solid laser crystal (1).Plating at speculum (2) face has higher transmittance to 1.3 mu m waveband total reflections, 1.0 mu m wavebands, outgoing mirror (3) is coated with to be had higher transmittance and 1.3 mu m wavebands the best is exported degree of coupling parameter 1.0 mu m wavebands, insert simultaneously acousto-optic modulator or the electro-optical modulator assembly (4) with slicing effect in resonant cavity, (5) are lamp (krypton lamp or xenon lamp) or with the pumping system of semiconductor laser.The chamber interpolation is gone into acousto-optic modulator to carrying out head and the tail slicing for pumping source or with the semiconductor laser for the pulse under the pumping source pumping at lamp (krypton lamp or xenon lamp), if in pulse, add the modulation (as shown in Figure 3) of 5-20 KHz, the pulse envelope of high several magnitudes of peak power, novel high-peak power pulse that this duty ratio is littler, the subpulse width only has hundreds of nanosecond and the super pulse CO of high energy will be produced ₂Shaping laser has difference, makes that Qi Daofeng is more sharp, eschar is littler, fire damage is lighter.

The present invention compares the useful effect that is had with background technology: it is compared with traditional quasi-continuous lasing, has that pulsewidth is short, peak power is high, a pulse rising and trailing edge is precipitous, do not have head and the tail is lower than energy under the eschar threshold value; Avoid traditional quasi-continuous lasing to cause laser surgey edge of a knife broad, be not suitable for the shortcoming of delicate procedure.Therefore, novel " the super pulse solid laser of 1.3 micron wavebands of time shaping " has bigger application prospect.

Now accompanying drawing is done the drawing explanation: Fig. 1 is super pulse laser and the comparison diagram of quasi-continuous lasing on time response; Fig. 2 is a laser cavity structure schematic diagram of the present invention; Fig. 3 is that the pulse of Fig. 1 adds formed pulse envelope after the modulation of 5-20 KHz; Fig. 4 is the pie graph of the super pulse crystal laser of the 1.3 micron wavebands example of lamp pumping time shaping of the present invention; Fig. 5 is the pie graph of the super pulse crystal laser of the 1.3 micron wavebands example of the laser diode side pumped time shaping of the present invention.

Further describe embodiments of the invention below in conjunction with accompanying drawing:

Embodiment one:

(1) is the Nd:YAG crystal among Fig. 4, (6) be pumping with krypton lamp or xenon lamp, (7) be the optical filtering pipe of elimination pumping lamp ultra-violet radiation, (11) hard-pressed bale formula ellipse or round laser pump cavity, be full of the medium cooling fluid in the chamber, cooling work material and pumping lamp, (3) be the outgoing mirror of laser, 1.0 mu m wavebands there is higher transmittance and 1.3 mu m wavebands the best is exported degree of coupling parameter, thereby make the loss difference of two kinds of wavelength lasers, to reach the laser that suppresses 1.0 mu m wavebands, only export the laser of 1.3 mu m wavebands.Here our the output degree of coupling that adopts is: the transmissivity to 1.319 μ m is 2.5%, is 80% to the transmissivity of 1.064 μ m; (8) be self-loopa cooling device, (9) are power supply, can export the pulse power of energy adjustable, and (2) are 99.8%, are 90% dielectric mirror to the transmissivity of 1.064 μ m the reflectivity of 1.319 μ m, (4) fused quartz crystal acousto-optic modulator.During work, if insert the nonlinear optics frequency-changer crystal in the chamber or outside the chamber, and the degree of coupling of corresponding adjustment resonator mirror, can obtain the coherent radiation output of higher conversion efficiency easily.

Embodiment two:

Among Fig. 5 (1) be the Nd:YAG crystal, with a plurality of LD (12) side-pumping, with the pump light vertical direction on heat sink (not the drawing among the figure) of semiconductor cooler refrigeration, extract the heat that the operation material operation process produces; (3) be the outgoing mirror of laser, 1.0 mu m wavebands had higher transmittance and export degree of coupling parameter to 1.3 mu m wavebands are best, thereby make the loss difference of two kinds of wavelength lasers,, only export the laser of 1.3 mu m wavebands to reach the laser that suppresses 1.0 mu m wavebands.Here our the output degree of coupling that adopts is: the transmissivity to 1.319 μ m is 2.5%, is 80% to the transmissivity of 1.064 μ m; (2) reflectivity of 1.319 μ m is 99.8%, is 90% dielectric mirror to the transmissivity of 1.064 μ m that (4) are fused quartz crystal acousto-optic modulator, (13) are the drive sources of LD semiconductor laser, and (14) are fused quartz crystal acousto-optic modulator driving power.Acousto-optic modulator works in several KHz to tens KHz, produces that peak power reaches kilowatt, the laser pulse envelope of the about a few percent of duty, and the width of envelope is several microseconds at zero point.

Claims (2)

1. the super pulse Nd-doped crystal laser of mu m waveband is with Nd:YAG, Nd:YVO ₄, a kind of laser crystal among Nd:YAP, Nd:YLF, the Nd:BEL is laser-activated medium, be pumping source or be under the pumping source at xenon lamp with the semiconductor laser, under pulsed mode, the super pulse 1.3 mu m waveband first-harmonics of this device output, concrete wavelength is as follows: to the Nd:YAG crystal is 1319nm or 1338nm; To Nd:YVO ₄Crystal is 1342nm; To the Nd:YAP crystal is 1341.4nm; To the Nd:YLF crystal is 1313nm; To the Nd:BEL crystal is 1351nm, it is characterized in that, the super pulse Nd-doped crystal laser of described 1.3 mu m wavebands has following structure: the mirror surface in the oscillator stage resonant cavity plates has higher transmittance to 1.3 mu m waveband total reflections, 1.0 mu m wavebands, outgoing mirror is coated with to be had higher transmittance and 1.3 mu m wavebands the best is exported degree of coupling parameter 1.0 mu m wavebands, insert the acousto-optic modulator or the electro-optical modulator assembly of 1.3 mu m wavebands simultaneously in resonant cavity, producing only has the rising edge of microsecond level and several millisecond laser pulses at steep zero point of trailing edge.

2. the super pulse Nd-doped crystal laser of 1.3 mu m wavebands as claimed in claim 1, it is characterized in that: described acousto-optic modulator or electro-optical modulator assembly work in several KHz to tens KHz, high several magnitudes of generation peak power, the laser pulse envelope that duty ratio is littler.

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