CN101237117A - Solid laser of LD pumping - Google Patents

Abstract

The invention discloses a solid laser for an LD pump, comprising an LD pump light source, a pump coupling lens and a laser cavity resonator having a laser crystal or optical elements except the laser crystal, wherein, the laser incoming surface of the laser cavity resonator is plated by a laser cavity front mirror film, the interface before the pump light enters the laser crystal is plated by a reflection reducing coating of the pump light, the laser outgoing surface of the laser cavity resonator is plated by a laser cavity rear mirror film, the interface after the pump light outgoes from the laser crystal is plated by a high-reflection coating of the pump light. By adopting the proposal, the pump light can be absorbed fully in double pass by plating special films on the laser cavity resonator interface, thereby reducing the threshold value and raising the transfer efficiency.

Description

A kind of solid state laser of LD pumping

Technical field the present invention relates to laser field, relates in particular to a kind of solid state laser of LD pumping.

Technical background is in the application of green (light) laser, in the laser display as construction account, Laser Point, microminiaturization, all need the laser that facular model is good, efficient is high, power consumption is little and cost is low, especially in laser display is used, power consumption, threshold value requirement to laser are high especially, simultaneously its size are also had strict restriction.The angle of divergence of common LD difference on both direction is big especially, in order to optimize the pump light pattern, raises the efficiency, reduces power consumption usually, need be to the pump light shaping, and this has just caused the shortcoming that the laser volume is big, price is high.The microchip frequency double laser of present ubiquitous employing LD pumping, its LD output is only without shaping, in order to increase the absorption of laser crystal to pump light, usually pass through to increase the thickness of laser crystal or improve doping content, but there are some tangible problems like this, extend such as laser crystal, pump light is after focusing in the laser crystal, in fact because the pump light angle of divergence is big, pump light can be dispersed very soon, hot spot becomes very big in the laser crystal rear end, and corresponding pump light density is very little, has not had too big effect; In addition, after crystal lengthening and the raising doping content, can cause usually absorbing and strengthen, promptly cavity loss increases, and so can reduce laser output power.And most laser crystals can produce quenching effect or absorption loss increase because concentration is high, so the concentration of laser crystal can not be De Taigao.

The summary of the invention goal of the invention provides the solid state laser of the LD pumping that a kind of facular model is good, efficient is high, power consumption is little and cost is low, especially the microchip solid state laser of LD pumping.

The present invention is by the following technical solutions: solid state laser comprises LD pump light source, pumping coupled lens, laserresonator, laserresonator comprises laser crystal, perhaps also comprise the optical element except that laser crystal, wherein the laser entrance face of laserresonator is coated with laser cavity front cavity mirror film system, the anti-reflection film of plating pump light on the interface before pump light enters laser crystal, the laser-emitting face of laserresonator is coated with laser cavity Effect of Back-Cavity Mirror film system, the highly reflecting films of plating pump light on the interface after pump light penetrates laser crystal.

The above-mentioned optical element except that laser crystal refers to nonlinear crystal, modulation device, modeling device or more than one elements combination wherein.

The present invention adopts above scheme, by the laserresonator interface being plated specific film system, realizes the round trip of pump light is fully absorbed, and has reduced threshold value, has improved conversion efficiency; Especially for the lower non-central wavelength band of gain coefficient, increase absorption effectively and reach oscillation threshold, fully widened the bandwidth utilized of pump light; Simultaneously, the repeatedly reflection of pump power light that fills the air also helps the absorption thermal effect of laser crystal to be tending towards to a certain extent evenly making pump light effectively be absorbed conversion at laser crystal, improves the laser cavity whole efficiency thus.Be specially adapted to the LD pump light and do not have the microchip frequency double laser of shaping.

Description of drawings now is further elaborated the present invention in conjunction with the accompanying drawings:

Fig. 1 is the optical structure chart schematic diagram of one of solid state laser of the present invention;

Fig. 2 is two an optical structure chart schematic diagram of solid state laser of the present invention;

Fig. 3 is three an optical structure chart schematic diagram of solid state laser of the present invention.

Embodiment sees also shown in Figure 1, the present invention includes LD pump light source 1, pumping coupled lens 2, laserresonator 3, laserresonator 3 can adopt discrete laser cavity or micro-piece type laser cavity, laserresonator 3 comprises laser crystal 31, doping content that laser crystal 31 is chosen and length, make its secondary that helps pump light absorb, form stable thermal lens; Wherein to be coated with laser cavity front cavity mirror film be 4 to the pump light plane of incidence of laser crystal 31, and it comprises the anti-reflection film of pump light, and it is 5 that the laser-emitting face of laser crystal 31 is coated with laser cavity Effect of Back-Cavity Mirror film, and it comprises the highly reflecting films 8 of pump light; Incide for the first time the pump light 6 of 31 li of laser crystals; Entered the pump light 7 of laser crystal 31 for the second time by highly reflecting films 8 reflections.When needing the laser of different wave length output, the material that laser crystal 31 is selected for use is just different, is Nd:YVO4 as laser crystal 31, and can be used for the LD pumping wavelength is the 1064nm laser of 808nm.

If the length of laser crystal 31 is l, its absorption coefficient to pump light is α, the average divergence angle of pump light is θ, because in general, the facular model of the LD of higher-wattage all is the high-order transverse mode, calculates for simplifying, and supposes that its energy is for evenly distributing, laser cavity front cavity mirror film is that the transmissivity of the anti-reflection film of pump light in 4 is made as 100%, and laser cavity Effect of Back-Cavity Mirror film is that the reflectivity of the high-reflecting film of pump light in 5 is R.As a kind of special case of simplification, it is that pumping light power is made as I on 4 the face that the focus point S that supposes pump light is laser cavity front cavity mirror film at the front end face of laser crystal 31 just.The average power density of pump light should be in above-mentioned laser crystal 31:

$I_{\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="S2008100706940E00011.png,S2008100706940E00021.png"\; state="\{\{state\}\}">p</figure-callout>}2}=\frac{1-e^{-\mathrm{\&alpha;}*2l}}{\mathrm{\&pi;}*{(\mathrm{\&theta;}*l)}^2}+\frac{3*(1-e^{-\mathrm{\&alpha;}*l})}{\mathrm{\&pi;}*{(\mathrm{\&theta;}*l)}^2}=I_{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100706940E00011.png,S2008100706940E00021.png"\; state="\{\{state\}\}">p</figure-callout>}1}+{\mathrm{\&Delta;I}}_p$

And habitually in the past for once under the absorbing state, in order to allow pump light absorb thoroughly, also in order to allow under the both of these case crystal absorption length relative, better relatively, establishing crystal length is 2l, and the average power density of pump light should be in laser crystal:

$I_{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008100706940E00011.png,S2008100706940E00021.png"\; state="\{\{state\}\}">p</figure-callout>}1}=\frac{1-e^{-\mathrm{\&alpha;}*2l}}{\mathrm{\&pi;}*{\left(\frac{\mathrm{\&theta;}*2l}{2}\right)}^2}=\frac{1-e^{-\mathrm{\&alpha;}*2l}}{\mathrm{\&pi;}*{(\mathrm{\&theta;}*l)}^2}$

Because Δ I _p＞0, so the average power density of pump light helps fully improving the effective rate of utilization of pump light greater than usual in the laser crystal of the present invention 31.

See also shown in Figure 2, the present invention includes LD pump light source 1, pumping coupled lens 2, laserresonator 3, laserresonator 3 comprises laser crystal 31, doping content that laser crystal 31 is chosen and length, make its secondary that helps pump light absorb, form stable thermal lens; Also comprise the optical element 32 except that laser crystal 31, wherein to be coated with laser cavity front cavity mirror film be 4 to the pump light plane of incidence of laserresonator 3, the anti-reflection film of plating pump light on the arbitrary interface before pump light enters laser crystal 31, it is 5 that the laser-emitting face of laserresonator 3 is coated with laser cavity Effect of Back-Cavity Mirror film, can plate the highly reflecting films 8 of pump light on the arbitrary interface after pump light penetrates laser crystal 31; Incide for the first time the pump light 6 of 31 li of laser crystals; Entered the pump light 7 of laser crystal 31 for the second time by highly reflecting films 8 reflections.Optical element 32 except that laser crystal 31 refers to element such as nonlinear crystals, modulation device, modeling device or more than one combination of elements etc. wherein, when it is frequency-doubling crystal, can be used for frequency double laser, select Nd:YVO4 such as laser crystal 31, optical element 32 except that laser crystal 31 selects frequency-doubling crystal KTP, and then this structure just will be exported the LD pumping intracavity frequency doubling laser of 532nm.

See also shown in Figure 3, the present invention includes LD pump light source 1, pumping coupled lens 2, laserresonator 3, laserresonator 3 comprises laser crystal 31, doping content that laser crystal 31 is chosen and length, make its secondary that helps pump light absorb, form stable thermal lens; Also comprise the optical element 32,33 except that laser crystal 31, wherein to be coated with laser cavity front cavity mirror film be 4 to the pump light plane of incidence of laserresonator 3, can plate the anti-reflection film of pump light on the arbitrary interface before pump light enters laser crystal 31, it is 5 that the laser-emitting face of laserresonator 3 is coated with laser cavity Effect of Back-Cavity Mirror film, can plate the highly reflecting films 8 of pump light on the arbitrary interface after pump light penetrates laser crystal 31; Incide for the first time the pump light 6 of 31 li of laser crystals; Entered the pump light 7 of laser crystal 31 for the second time by highly reflecting films 8 reflections.Optical element 32 except that laser crystal 31 comprises frequency-doubling crystal etc., optical element 33 except that laser crystal 31 refers to element such as nonlinear crystals, modulation device, modeling device or more than one combination of elements etc. wherein, when the optical element except that laser crystal 31 32 is a frequency-doubling crystal, can be used for frequency double laser, when the optical element except that laser crystal 31 33 is elements such as different nonlinear crystal, modulation device, modeling device or more than one combination of elements etc. wherein, can be used for the laser of other different function.

In the above-mentioned structure of the present invention, laser crystal 31 constitutes by a crystal or by the polylith crystal, and when being made of the polylith crystal, the highly reflecting films of pump light can be plated on the interface after pump light penetrates each laser crystal 31.The film system that each optical element surface plated can be according to concrete needs optimal design index, to regulate control effectively.

Claims (4)

1, a kind of solid state laser of LD pumping, comprise LD pump light source, pumping coupled lens, laserresonator, laserresonator comprises laser crystal, perhaps also comprise the optical element except that laser crystal, it is characterized in that: the laser entrance face of laserresonator is coated with laser cavity front cavity mirror film system, the anti-reflection film of plating pump light on the interface before pump light enters laser crystal, the laser-emitting face of laserresonator is coated with laser cavity Effect of Back-Cavity Mirror film system, the highly reflecting films of plating pump light on the interface after pump light penetrates laser crystal.

2, the solid state laser of a kind of LD pumping according to claim 1 is characterized in that: doping content that its laser crystal is chosen and length, and make its secondary that helps pump light absorb, form stable thermal lens.

3, the solid state laser of a kind of LD pumping according to claim 1 is characterized in that: the optical element except that laser crystal refers to nonlinear crystal, modulation device, modeling device or more than one elements combination wherein.

4, the micro-slice laser of a kind of LD pumping according to claim 1, it is characterized in that: laser crystal constitutes by a crystal or by the polylith crystal, when being made of the polylith crystal, the highly reflecting films of pump light can be plated on the interface after pump light penetrates first block of laser crystal.

Images