CN2842820Y - Single-frequency microchip laser - Google Patents

Abstract

A kind of single-frequency micro-slice laser; comprise LD pump light source, collimation and Focused Optical system, chamber mirror; the birefringence rhomboidan prism that is positioned at laser cavity is as the polarizer; and frequency selective device in the birefringece crystal wave plate formation chamber, thereby the microchip and the discrete laser of acquisition single longitudinal mode fundamental frequency, frequency multiplication.

Description

The single-frequency micro-slice laser

[technical field]

The utility model is about a kind of laser, is meant a kind of single-frequency micro-slice laser especially.

[background technology]

In field of lasers, single frequency laser has a wide range of applications.The existing multiple mode of people obtains single longitudinal mode laser output, and wherein adopting birefringece crystal wave plate and Brewster plain film to constitute the frequency-selecting structure is a kind of typical way.But it is less by loss on Brewster sheet surface that the shortcoming of this scheme is the S component, and the limit mould is indifferent, only uses in some low-power and discrete chamber.

[summary of the invention]

Technical problem to be solved in the utility model is to provide a kind of microchip and discrete laser that obtains single longitudinal mode fundamental frequency, frequency multiplication.

The utility model solves the problems of the technologies described above by the following technical programs: a kind of single-frequency micro-slice laser, comprise LD pump light source, collimation and convergence optical system, chamber mirror, the birefringence rhomboidan prism that is positioned at laser cavity is as the polarizer, and the birefringece crystal wave plate constitutes frequency selective device in the chamber.

Optical element can be discrete in the described laser cavity, or adopts optical cement, in-depth optical cement or directly glued together with glue.

The laser cavity inner laser satisfies total internal reflection by rhomboidan prism e light, and o light does not satisfy total internal reflection and major part sees through.

Perhaps the laser cavity inner laser satisfies total internal reflection by rhomboidan prism o light, and e light does not satisfy total internal reflection and major part sees through.

Rhomboidan prism and birefringece crystal wave plate have angle between optical direction glazing axial projection direction.

Also can insert frequency-doubling crystal between rhomboidan prism and the laser cavity outgoing mirror in the laser cavity.Wherein the optical axis of birefringece crystal wave plate is positioned at the angular bisector direction of frequency-doubling crystal and rhomboidan prism optical axis included angle.

The advantage of the utility model single-frequency micro-slice laser is: adopt special rhombus birefringece crystal prism to constitute frequency selective device in the laser cavity as the polarizer and birefringece crystal wave plate, thereby obtain single longitudinal mode fundamental frequency, the microchip of frequency multiplication and discrete laser.

[description of drawings]

The utility model will be further described in conjunction with example with reference to the accompanying drawings.

Fig. 1 is the schematic diagram of the utility model single-frequency micro-slice laser.

Fig. 2 is the optical axis direction of rhomboidan prism on optical direction among Fig. 1.

Fig. 3 is the optical axis direction of birefringece crystal wave plate on optical direction among Fig. 1.

Fig. 4 is the schematic diagram of opticpath when rhomboidan prism optical axis is parallel to the plane of incidence among Fig. 1, wherein n _e＞n _o

Fig. 5 is the schematic diagram of opticpath when rhomboidan prism optical axis is perpendicular to the plane of incidence among Fig. 1, wherein n _e＞n _o

Fig. 6 is the schematic diagram of opticpath when rhomboidan prism optical axis is parallel to the plane of incidence among Fig. 1, wherein n _o＞n _e

Fig. 7 is the schematic diagram of opticpath when rhomboidan prism optical axis is perpendicular to the plane of incidence among Fig. 1, wherein n _o＞n _e

Fig. 8 is the schematic diagram that the utility model single-frequency micro-slice laser is used for the output of I class frequency multiplication single longitudinal mode.

Fig. 9 is the principle assumption diagram of end pumping when the rhomboidan prism is as the birefringece crystal gain medium in the utility model single-frequency micro-slice laser.

Figure 10 is that Fig. 9 is from the pumping of rhombus gain media prism side.

Figure 11 to Figure 14 directly glues together schematic diagram between each optical element.

Figure 15 and Figure 16 are the structural representation that inserts wave plate in light path.

Wherein: 101 is the laser cavity front cavity mirror, and 102 is gain medium, and 103 is the rhomboidan prism, and 104 is the birefringece crystal wave plate, and 105 is the laser cavity outgoing mirror, and 106 are collimation participant optically focused system, and 107 is the LD pump light source; 201 for being plated in the front cavity mirror rete on the plane of crystal, and 202 is gain medium, and 203 is rhombus birefringece crystal prism, and 204 is the birefringece crystal wave plate, and 205 for being plated in the Effect of Back-Cavity Mirror rete on the plane of crystal, and 209 is I class or II class frequency-doubling crystal

[embodiment]

See also Fig. 1, the utility model single-frequency micro-slice laser comprises laser cavity front cavity mirror 101, gain medium 102, rhomboidan prism 103, birefringece crystal wave plate 104, laser cavity outgoing mirror 105, collimation and convergence optical system 106, and LD pump light source 107.

Fig. 2, Fig. 3 represent rhomboidan prism 103, the optical axis direction of birefringece crystal wave plate 104 on optical direction respectively, and promptly birefringece crystal wave plate 104 is ∮ with rhomboidan prism 103 optical axis included angle on optical direction, and general ∮ gets 45 °.

The design principle of this single-frequency micro-slice laser is: rhomboidan prism 103 is to utilize birefringece crystal o light different with the e optical index and design, and selects special water caltrop angle θ, establishes n _eAlinternal reflection angle is θ _e(n _eSin θ _e=1), n _oAlinternal reflection angle is θ _o(n _oSin θ _o=1):

1) if n _e＞n _o, θ then _e＜θ _o, get θ _e＜θ＜θ _o

Then e light total internal reflection, the wide part transmission of o.

As Fig. 4 and shown in Figure 5, wherein rhomboidan prism 103 optical axises are parallel to the plane of incidence among Fig. 4;

Rhomboidan prism 103 optical axises are perpendicular to the plane of incidence among Fig. 5.

2) if n _o＞n _e, θ then _o＜θ _e, get θ _o＜θ＜θ _e

Then o light total internal reflection, the most of transmission of e.

As Figure 6 and Figure 7, wherein rhomboidan prism 103 optical axises are parallel to the plane of incidence among Fig. 6;

Rhomboidan prism 103 optical axises are perpendicular to the plane of incidence among Fig. 7.

When the polarised light that produces from rhomboidan prism 103 during by birefringece crystal wave plate 104, because the ∮ angle exists, polarised light will be divided into o light and e light, and o light and e light differ Δ back and forth for they _λFor:

${\mathrm{\Δ}}_{\mathrm{\λ}}=\frac{4\mathrm{\π}(n_o-n_e)l}{\mathrm{\λ}}$

Different λ is pairing differs different, has only Δ _λ=(2n+1) π (n=0,1,2 ...) be that birefringece crystal wave plate 104 is during for half-wave plate and full-wave plate, light is minimum by the 103 generation losses of rhomboidan prism, when birefringece crystal wave plate 104 length make gain wavelength scope phasic difference value less than π, then might only make a wavelength starting of oscillation, thereby realize the single longitudinal mode running, promptly

Δ _{The λ maximum}-Δ _{The λ minimum}＜π

In sum, among Fig. 1 rhomboidan prism 103 at Fig. 4, Fig. 5, Fig. 6 all can be used as the frequency-selecting element and obtains single longitudinal mode laser output under four kinds of situations of Fig. 7.

1) when birefringece crystal wave plate 104 is common double refracting crystal wave plate, Fig. 1 structure is a single longitudinal mode output basic frequency laser device;

2) when birefringece crystal wave plate 104 be II class birefringence frequency-doubling crystal, then frequency-doubling crystal has dual-use function, the one, as the birefringece crystal wave plate, the 2nd, produce frequency doubled light, then Fig. 1 structure is a single longitudinal mode output frequency double laser;

3) this structure also can be used for the output of I class frequency multiplication single longitudinal mode, and as shown in Figure 8, wherein the function of each element is identical with Fig. 1 element function, and 109 is I class frequency-doubling crystal;

4) when rhomboidan prism 103 was the birefringece crystal gain medium, then Fig. 1 structure chart became Fig. 9, Figure 10, and wherein Fig. 9 is an end pumping, and Figure 10 is from the pumping of rhombus gain media prism side.

The utility model said structure is the discrete cavity configuration, and the utility model also can adopt optical cement, in-depth optical cement or adhesive means each crystal that bonds, as Figure 11 to shown in Figure 14.Wherein, 201 for being plated in the front cavity mirror rete on the plane of crystal, laser cavity front cavity mirror 101 in the corresponding diagram 1,202 is gain medium, gain medium 102 in the corresponding diagram 1,203 is rhombus birefringece crystal prism, rhomboidan prism 103 in the corresponding diagram 1,204 is the birefringece crystal wave plate, birefringece crystal wave plate 104,205 is for being plated in the Effect of Back-Cavity Mirror rete on the plane of crystal, corresponding to laser cavity outgoing mirror 105 among Fig. 1 in the corresponding diagram 1,209 is I class or II class frequency-doubling crystal, II class frequency-doubling crystal 109 in the corresponding diagram 1.Here, Figure 11 operation principle corresponding diagram 1; Figure 12 operation principle corresponding diagram 8; Figure 13, Figure 14 operation principle corresponding diagram 9 no longer repeat to tell about here.

In actual applications, for improving the temperature stability and the extinction ratio of laser, can insert wave plate in light path, be that full-wave plate, frequency doubled light are half-wave plate to fundamental frequency light.As shown in figure 15,206 is wave plate, its optical axis is positioned at the angular bisector direction of II class frequency-doubling crystal 209 and rhombus birefringece crystal prism 203 both optical axis included angles, when oppositely frequency doubled light is by rhombus birefringece crystal prism 203, the part transmission takes place on S1, S2 face, process gain medium 202 is reflected back rhombus birefringece crystal prism 203 again, still have part light can be transmitted to outside the chamber, like this, the return light that turns back to II class frequency-doubling crystal 209 is just very weak, improve the output extinction ratio, and can eliminate phase appearance that the return interference of light the brings problem that disappears.Certainly, high anti-to 205 plating frequency doubled lights, S1 face plating frequency doubled light is anti-reflection, and S1 as the output cavity mirror, also can be reached similar effects.In addition, as shown in figure 16, can also before gain medium 209, insert identical non-gain crystal, make both light shaft positive cross, reach stable output by phase compensation.

Claims (10)

1. single-frequency micro-slice laser, comprise LD pump light source, collimation and convergence optical system, laser cavity front cavity mirror, laser cavity outgoing mirror is characterized in that: comprise the birefringence rhomboidan prism that is positioned at laser cavity as the polarizer, and the birefringece crystal wave plate constitutes frequency selective device in the chamber.

2. single-frequency micro-slice laser as claimed in claim 1 is characterized in that: described laser cavity optical element adopts discrete optical element to constitute.

3. single-frequency micro-slice laser as claimed in claim 1 is characterized in that: the laser cavity inner laser satisfies total internal reflection by rhomboidan prism e light, and the o light transmission.

4. single-frequency micro-slice laser as claimed in claim 1 is characterized in that: the laser cavity inner laser satisfies total internal reflection by rhomboidan prism o light, and the e light transmission.

5. single-frequency micro-slice laser as claimed in claim 1 is characterized in that: rhomboidan prism and birefringece crystal wave plate have angle between optical direction glazing axial projection direction.

6. single-frequency micro-slice laser as claimed in claim 1 is characterized in that: comprise the frequency-doubling crystal that is arranged between rhomboidan prism and the laser cavity outgoing mirror.

7. single-frequency micro-slice laser as claimed in claim 6 is characterized in that: the optical axis of birefringece crystal wave plate is positioned at the angular bisector direction of frequency-doubling crystal and rhomboidan prism optical axis included angle.

8. single-frequency micro-slice laser as claimed in claim 1 is characterized in that: described laser cavity optical element adopts optical cement, in-depth optical cement or close with the direct chamber of glue.

9. single-frequency micro-slice laser as claimed in claim 1 is characterized in that: comprise being inserted in the gain medium before the rhomboidan prism in the laser cavity.

10. single-frequency micro-slice laser as claimed in claim 9 is characterized in that: comprise being inserted in the preceding identical non-gain crystal of laser cavity inner laser gain media.

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