CN106911064A

CN106911064A - Phase compensation type rastering laser resonator

Info

Publication number: CN106911064A
Application number: CN201510968814.9A
Authority: CN
Inventors: 李国富; 多丽萍; 金玉奇; 王增强; 王元虎; 唐书凯; 李留成; 于海军; 汪健; 曹靖; 康元福
Original assignee: Dalian Institute of Chemical Physics of CAS
Current assignee: Dalian Institute of Chemical Physics of CAS
Priority date: 2015-12-22
Filing date: 2015-12-22
Publication date: 2017-06-30
Anticipated expiration: 2035-12-22
Also published as: CN106911064B

Abstract

The present invention is a kind of phase compensation type rastering laser resonator, is related to laser optics resonator and laser frequency-selecting technology.Rastering laser resonator of the invention is made up of concave spherical mirror or convex spherical speculum, No. 1 grating and No. 2 gratings and laser output mirror.Concave spherical mirror, No. 1 grating, No. 2 gratings and laser output mirror form laser beam axis, and optical axis is not equal to the blaze angle of grating with the angle of grating normal.Rastering laser resonator of the invention can solve the problem that the laser facula that grating causes under non-auto-collimation working condition changes on optical grating diffraction direction.Suitable for various tunable laser such as carbon dioxide laser and hydrogen fluoride laser.

Description

Phase compensation type rastering laser resonator

Technical field

The present invention relates to field of laser device technology, more particularly to grating as laser frequency-selecting device in non-autocollimatic Hot spot amendment in the case of straight.

Background technology

Grating has extraordinary dispersive power, is widely used in spectrometer and laser frequency-selecting output.Light Grid as hysteroscope a part, be on the one hand the ability that there is spectral dispersion using it, on the other hand It is then using its plane reflection feature.In general practical application grating it is many in autocollimatic mode (i.e.： Incident light is incident with the angle at optical grating diffraction angle) form stable cavity or unsteady cavity with other optical elements. Grating is with non-autocollimatic mode application, compared to autocollimatic Nogata in some special laserresonators Formula, this mode can cause hot spot to become big on optical grating diffraction direction or diminish, such as Fig. 1 (a), (b) institute Show, Fig. 1 (a) is auto-collimation mode, Fig. 1 (b) is non-auto-collimation mode.

Grating equation is d (sin (β)+sin (θ))=n λ, and wherein β is incident light and grating normal Angle, θ is the angle of emergence of different diffraction level and diffraction wavelength.As n=1 and β=θ₀When be grating auto-collimation Condition, i.e. incident light are with the blaze angle θ of grating₀Incidence, now the one-level primary maximum blaze wavelength of grating is λ. If optical axis and the blaze angle θ that the angle of grating normal is grating₀, then λ be optical maser wavelength.

Fig. 1 (b) is the non-auto-collimation stable cavity schematic diagram of grating.As a diameter of D of launching spot_i, then it is not at the same level Spot diameter of the secondary emergent light spot in diffraction direction be：

D_o=D_i/cos(β)*cos(θ)

Output angle θ can be calculated by grating equation, so emergent light spot is with the diameter ratio of launching spot：

Fig. 4 is the diameter of emergent light spot and launching spot than change curve (the grating diffration angle with incident angle It is θ₀=30 °, n=1, λ/d=1).As can be seen from Figure when incidence angle is more than optical grating diffraction angle, light Spot is exaggerated in diffraction direction, and when incidence angle is less than optical grating diffraction angle, hot spot is contracted on diffraction direction mountain It is small.

The content of the invention

Present invention aim at for such grating optical resonator provides a kind of phase compensation and restores optical grating diffraction A kind of method of direction hot spot.

In order to realize the purpose of the present invention, specific technical scheme is：

For the non-auto-collimation laserresonator of grating of Fig. 1 (b), solution proposed by the present invention is, in light Intra-cavity phase null grating is added in the exit direction of grid, as shown in Figure 2.It is required that the sudden strain of a muscle of phase compensation grating Credit angle, blaze wavelength and grating constant are identical with one block of other grating.Can be calculated according to grating equation The angle for going out emergent light with grating normal is θ.Realize phase compensation, the angle of incident light of phase compensation grating Degree is most important, and the incident light of phase compensation grating should be θ with the angle of grating normal.In phase compensation light The exit direction of grid installs one piece of hysteroscope, for forming feedback and exporting.

Rastering laser resonator of the invention can solve the problem that the laser that grating causes under non-auto-collimation working condition Hot spot changes on optical grating diffraction direction.

Brief description of the drawings

Fig. 1 is monochromatic light grid auto-collimation ((a)) and non-auto-collimation stable cavity ((b)) structural representation；

Fig. 2 is schematic structural view of the invention；

In figure：(1)：Resonator concave spherical mirror, (2)：No. 1 grating, (3)：Resonator outgoing mirror, (4)： Gain media, (5)：No. 2 gratings；

Fig. 3 is embodiments of the invention；

In figure：(1)：Resonator concave spherical mirror, (2)：No. 1 grating, (3)：Resonator outgoing mirror (4)： Gain media, (5)：No. 2 gratings：(6)：Convex spherical speculum；

Fig. 4 is diameter than the change curve with incident angle (grating diffration angle is 30 °).

Specific embodiment

To further illustrate feature of the invention and structure, the present invention is described in detail below in conjunction with accompanying drawing.

It is grating auto-collimation laserresonator schematic diagram refering to Fig. 1 (a).Resonator is by the He of concave spherical mirror 1 Reflective gratings 2 are constituted, and the normal direction of concave spherical mirror and the angle of grating normal are grating diffration angle. When the reflectivity in 0 order diffraction direction of reflective gratings is suitable, can make using in 0 grade of direction of grating It is the light direction of laser.If the reflectivity in 0 order diffraction direction of grating is improper, can be by recessed ball Face speculum replaces with concave spherical surface diaphotoscope, and laser is exported from concave spherical mirror direction.In order to realize work(higher Rate is exported, and is tested using the concave spherical surface diaphotoscope of different transmitances.

Fig. 1 (b) is the non-auto-collimation laserresonator schematic diagram of grating.Resonator is by concave mirror 1, reflecting light Grid 2 and flat output mirror are constituted, and normal direction and the angle of grating normal of concave spherical mirror are more than or less than Grating diffration angle.The laser output window of this non-auto-collimation rastering laser resonator is level crossing, can be with Optimal power output is realized by the transmitance for changing level crossing.

Fig. 2 is phase compensation rastering laser resonator schematic diagram of the invention.Laserresonator of the invention is by recessed 1, No. 1 grating 2 of spherical reflector, (plane is defeated for 4, No. 2 resonant cavity outgoing mirrors 3 of grating 5 of gain media Appearance) composition.After wherein the laser of concave spherical mirror normal direction amplifies through gain media, by No. 1 Overlapped with the normal of resonator outgoing mirror after grating and No. 2 optical grating reflections, partly on resonator outgoing mirror surface Backtracking forms laser generation (another part transmission output) after reflection.Feelings are collimated in laserresonator optical cavity Under condition, the normal of concave spherical mirror is the optical axis of resonator, by No. 1 grating and No. 2 optical grating reflections Laser overlaps with the normal of resonator outgoing mirror afterwards.According to design of the invention, hot spot in Fig. 1 (b) is solved Become the big design parameter and placement location parameter that it is critical only that No. 2 gratings 5 in diffraction direction.No. 2 gratings 5 With No. 1 grating constant of grating 2, blaze wavelength λ and flare angle θ₀Completely the same, optimal situation It is that two blocks of gratings are obtained for same mother matrix (original carves grating) is replicated.No. 2 placement locations of grating are located at No. 1 light The exit direction of grid and with No. 1 parallel gratings, No. 1 grating diffration light is 2 with the angle of grating normal The angle of number grating incidence light and grating normal.

Fig. 3 is embodiments of the invention, and convex spherical speculum 6 therein is embedded in flat output mirror, and (resonator is defeated Appearance 3) on.Concave spherical mirror 1 and the plated surface high-reflecting film of convex spherical speculum 6, this two pieces of speculums with Two blocks of gratings 2 and 5 form empty telescope system chamber.The plated surface high transmission filter medium film of resonator outgoing mirror 3, Laser exports hollow annular hot spot from this window；No. 1 θ=50 degree of grating (incidence angle), θ₀=30 degree (are dodged Credit angle), θ is more than θ₀。

Claims

1. a kind of phase compensation rastering laser resonator, by concave spherical mirror or convex spherical speculum, 1 Number reflecting grating, No. 2 reflecting gratings and laser output coupling mirror composition, it is characterised in that：Concave spherical mirror Or convex spherical speculum and No. 1 reflecting grating are located at the laser gain medium area left and right sides respectively, No. 2 anti- Penetrate grating and laser output coupling mirror is placed in laser gain medium area outside, No. 1 reflecting grating is anti-with No. 2 Parallel gratings are penetrated to be oppositely arranged；Concave spherical mirror or convex spherical speculum are relative with No. 1 reflecting grating to be set Put；Laser output coupling mirror is oppositely arranged with No. 2 reflecting gratings.

2. rastering laser resonator as claimed in claim 1, it is characterised in that：Concave spherical mirror or Convex spherical speculum, No. 1 reflecting grating, No. 2 reflecting gratings and laser output coupling mirror form optical axis, the light Angle between axle and grating normal is non-auto-collimation more than or less than block grating of grating diffration angle, i.e., two In the case of work.

3. rastering laser resonator as claimed in claim 1, it is characterised in that：No. 1 reflecting grating It is the laser gain area of laser between concave spherical mirror or convex spherical speculum；No. 1 reflecting grating master It act as laser frequency-selecting, No. 2 reflecting grating Main Functions are hot spot amendment, and No. 1 reflecting grating and No. 2 Optical parameter (grating constant, blaze wavelength λ and the flare angle θ of reflecting grating₀) strict conformance.

4. the rastering laser resonator as described in claim 1 or 3, it is characterised in that：Described No. 2 are anti- Grating is penetrated with the angle of optical axis is determined by the angle of No. 1 reflecting grating and optical axis；If No. 1 reflected light The flare angle of grid is θ₀, concave spherical mirror or convex spherical speculum are reflexed in No. 1 reflecting grating The angle of incident light and No. 1 reflecting grating normal is β, then No. 1 reflecting grating reflexes to No. 2 reflecting gratings On incident light and the angle of No. 2 reflecting grating normals should be asin (λ/d-sin β), grating constant dodges Credit wavelength X.

5. rastering laser resonator as claimed in claim 1, it is characterised in that described concave spherical surface reflection Mirror or convex spherical speculum are gold-plated or deielectric-coating silicon base speculum, described laser output coupling Mirror is the laser output mirror with certain transmitance for plating deielectric-coating white stone or quartz.

6. rastering laser resonator as claimed in claim 1, it is characterised in that described concave spherical surface reflection Mirror or convex spherical speculum, No. 1 reflecting grating, No. 2 reflecting gratings and laser output coupling mirror form laser Optical axis.

7. rastering laser resonator as claimed in claim 1, it is characterised in that a convex spherical speculum is embedding In resonator outgoing mirror；Concave spherical mirror (1) and convex spherical mirror surface plating high-reflecting film, this two pieces Speculum and two blocks of gratings form empty telescope system chamber.