CN206057694U - A kind of axicon lens ring type laser irradiating device - Google Patents

Abstract

This utility model provides a kind of axicon lens ring type laser irradiating device, which includes coaxial the first plano-convex axicon lens being placed in parallel and the second plano-convex axicon lens, the first plano-convex axicon lens is identical with the refractive index of the second plano-convex axicon lens, the conical surface of the first plano-convex axicon lens is identical with the conical surface direction of the second plano-convex axicon lens, the base angle of base angle of the base angle of the first plano-convex axicon lens less than the second plano-convex axicon lens, the first plano-convex axicon lens and the second plano-convex axicon lens is respectively less than 5 °.Compared with the prior art, the beneficial effects of the utility model are：The drawbacks of a kind of axicon lens ring type laser irradiating device that this utility model is provided is needed in solving prior art by moving into repeatedly, removing axicon lens to realize 0 side-play amount, it is to avoid due to the irradiation non-uniformity that resetting causes.

Description

A kind of axicon lens ring type laser irradiating device

Technical field

This utility model is related to material internal component detecting devices field, and in particular to a kind of axicon lens ring type laser irradiation Device.

Background technology

Spatial deviation Raman spectroscopy (SORS) is a kind of new spectral measurement methodses for occurring in recent years, with tradition drawing Graceful spectral technique is compared, and in its spectral collection system, the focus of collecting lens spatially has a spacing with the focus of incident laser From skew.Due to (diffusely scattering media) on laser light incident to sample, the laser intensity of sample interior can be with incident depth Increase and exponential decay, produced a part of scattered light will reach sample Deep composition, and sample is returned again to Jing after Multiple Scattering Product surface.Therefore, on sample surfaces, generate at position and the exciting light incidence point that scattered light is returned different degrees of inclined Move.If be collected to scattered light at certain deviation post, you can obtain carrying measured matter component inside structural information Raman light.In SORS technologies, Raman signal excites-particularity of collection structure so as to draw with top layer composition is suppressed well The ability of graceful and fluorescence spectrum, is particularly well-suited to the extraction to subgrade composition Raman spectrum under non-transparent material, and then realizes thing Quick, the Nondestructive Identification of matter composition.The detection of powder, colloid, polymer and medicine, cultural heritage identification, disease are had been used at present In the research and application of the aspects such as diagnosis, contraband safety check, application prospect is extremely wide.

In practical application, the key issue that SORS technologies need to be solved be improve detectivity, that is, increase investigation depth and The signal to noise ratio of measurement signal is improved, and the laser radiation mode for being adopted determines which is applied to laser power on testing sample Size, and then have influence on the depth of interaction of laser and sample, inspire the intensity and its signal to noise ratio of Raman signal.The U.S. M.V.Schulmerich adopts axicon lens and the box-like irradiation structure of lens group, overcomes the point that the SORS technical research initial stages adopt The drawbacks of laser energy is not enough in formula irradiation structure, enhances the laser power being applied on testing sample, makes the drawing collected Graceful signal enhancing；The irradiation structure of Britain's rd's A Pu Islington laboratorys more simplifies, and its optical element is only a piece of cone Lens.Said two devices realize continuously adjustabe of the side-play amount from 0 beginning on two-dimensional space, but still suffer from certain deficiency：Non-zero sky Between side-play amount movement of the change by axicon lens on optical path direction realizing, and when measuring to the spectrum of 0 side-play amount, Optical element need to be removed from light path.So it is movable into and out repeatedly, easily causes the difference of translation stage resetting, increases The unstability of system.

In view of drawbacks described above, it is new that this utility model creator obtains this practicality finally through prolonged research and practice Type.

Utility model content

To solve above-mentioned technological deficiency, the technical solution adopted in the utility model is, there is provided a kind of axicon lens ring type swashs Light-irradiating device, when which is applied to spatial deviation Raman spectrum measurement system, it is not necessary to axicon lens is removed in light path with regard to energy The spectral measurement of 0 side-play amount is realized enough.

A kind of axicon lens ring type laser irradiating device is provided, when laser beam irradiates thereon, which can produce annular Radiation source, which includes coaxial the first plano-convex axicon lens being placed in parallel and the second plano-convex axicon lens, and the first plano-convex cone is saturating Mirror is identical with the refractive index of the second plano-convex axicon lens, and the conical surface of the first plano-convex axicon lens and second plano-convex cone are saturating The conical surface direction of mirror is identical, the base angle of the base angle of the first plano-convex axicon lens less than the second plano-convex axicon lens, and described the The base angle of one plano-convex axicon lens and the second plano-convex axicon lens is respectively less than 5 °.

Preferably, when the distance between the first plano-convex axicon lens and the second plano-convex axicon lens are d₁When, it is described 0 side-play amount exposure spots of the generation of axicon lens ring type laser irradiating device are apart from the second plano-convex axicon lens apart from d₂Meet Formula：

Wherein, n is the refractive index of the first plano-convex axicon lens and the second plano-convex axicon lens, θ₁For the bottom of the first plano-convex axicon lens Angle, θ₂For the base angle of the second plano-convex axicon lens, r₀It is the laser beam radius after expanding, b is the bottom of the second plano-convex axicon lens Width, a is the radius of the second plano-convex axicon lens, 0 ° of ＜ θ₁＜ θ₂5 ° of ＜.

Preferably, working as the distance between the first plano-convex axicon lens and the second plano-convex axicon lens d₁When immobilizing, change Become 0 side-play amount exposure spots with the second plano-convex axicon lens apart from d₂, you can obtain continually varying annular radiation source, the annular The internal diameter r of radiation source₂Meet formula：

r₂=(d₂-d)·cot(n-1)(θ₂-θ₁)

Wherein, d is annular the distance between radiation source and the second plano-convex axicon lens.

The beneficial effects of the utility model are compared with the prior art：A kind of axicon lens ring type that this utility model is provided The drawbacks of laser irradiating device is needed in solving prior art by moving into repeatedly, removing axicon lens to realize 0 side-play amount, keeps away The irradiation non-uniformity caused due to resetting is exempted from.

Description of the drawings

For the technical scheme being illustrated more clearly that in each embodiment of this utility model, below will be to institute in embodiment description The accompanying drawing that needs are used is briefly described.

A kind of structural representation of axicon lens ring type laser irradiating device that Fig. 1 is provided for this utility model；

Fig. 2 is the light path principle after the laser beam after expanding is radiated at the axicon lens ring type laser irradiating device Figure；

Fig. 3 is a kind of schematic diagram of spatial deviation Raman spectroscopic detection system.

Specific embodiment

It is below in conjunction with accompanying drawing, above-mentioned to this utility model to be described in more detail with other technical characteristic and advantage.

As shown in figure 1, the structural representation of a kind of axicon lens ring type laser irradiating device that Fig. 1 is provided for this utility model Figure, the axicon lens ring type laser irradiating device include：Coaxial the first plano-convex axicon lens 1 being placed in parallel and the second plano-convex axicon lens 2, the first plano-convex axicon lens 1 is identical with the refractive index of the second plano-convex axicon lens 2, the conical surface and second of the first plano-convex axicon lens 1 The conical surface direction of plano-convex axicon lens 2 is identical, the base angle of the base angle of the first plano-convex axicon lens 1 less than the second plano-convex axicon lens 2, and first The base angle of plano-convex axicon lens 1 and the second plano-convex axicon lens 2 is respectively less than 5 °.When the laser after expanding is bored along above-mentioned two plano-convex After the optical axis direction of lens incides the plane of the first plano-convex axicon lens 1, the New type conical lens ring type laser irradiating device is with regard to energy It is enough to produce annular radiation source.

When the distance between the first plano-convex axicon lens 1 and the second plano-convex axicon lens 2 are d₁When, the New type conical lens ring type swashs Light-irradiating device produce 0 side-play amount exposure spots the second plano-convex of distance axicon lens 2 apart from d₂Meet formula (1)：

Wherein, n is the refractive index of the first plano-convex axicon lens 1 and the second plano-convex axicon lens 2, θ₁For the first plano-convex axicon lens 1 Base angle, θ₂For the base angle of the second plano-convex axicon lens 2, r₀It is the laser beam radius after expanding, b is that the second plano-convex cone is saturating The bottom width of mirror 2, a is the radius of the second plano-convex axicon lens 2,0 ° of ＜ θ₁＜ θ₂5 ° of ＜.

As the distance between the first plano-convex axicon lens 1 and the second plano-convex axicon lens 2 d₁When immobilizing, change 0 side-play amount Exposure spots are with the second plano-convex axicon lens 2 apart from d₂, you can obtain continually varying annular radiation source, the annular radiation source Internal diameter r₂Meet formula (2)：

r₂=(d₂-d)·cot(n-1)(θ₂-θ₁) (2)

Wherein, d is annular the distance between radiation source and the second plano-convex axicon lens 2.

The process for how obtaining above-mentioned formula is described below, as shown in Fig. 2 being that laser beam after expanding is radiated at Light path principle figure after the axicon lens ring type laser irradiating device,

If it is α that light beam incides the angle of incidence of the first plano-convex axicon lens 1, incident ray and refracted light angle are β, refraction Angle is γ, can be obtained by the law of refraction：

α=θ₁, γ=alpha+beta (3)

Nsin α=1sin γ=1sin (alpha+beta) (4)

Due to the base angle θ of the first plano-convex axicon lens 1₁Less than 5 °, (4) formula can be equivalent to：

N α=alpha+beta (5)

I.e.：β=(n-1) α=(n-1) θ₁ (6)

Dot spacing is submitted from AB=d in optical axis OO ' in the summit and light beam that the first plano-convex axicon lens 1 is made in Fig. 2₀, two cones are thoroughly Apart from AQ=d between mirror₁, the internal radius that light beam is formed on the second plano-convex axicon lens 2 are r₁, can obtain：

r₁=(d₁-d₀) tan β=(d₁-d₀) tan [(n-1) α]=d₁·tan[(n-1)θ₁]-r₀ (8)

If the angle of incidence of unirefringence is β in the second plano-convex axicon lens 2, refraction angle is β₁, the angle of incidence of birefringence is β₂, refraction angle is γ₂, can be obtained by the law of refraction：

1sin β=nsin β₁ (9)

n·sinβ₂=1sin γ₂ (10)

Due to the base angle θ of the second plano-convex axicon lens 2₂Less than 5 °, formula (9) and (10) can be equivalent to respectively：

β=n β₁, n β₂=γ₂ (11)

From geometrical relationship：β₁+β₂=θ₂ (12)

It is available by formula (11) and (12)：

γ₂=n β₂=n (θ₂-β₁)=n θ₂-β (13)

Work as γ₂=θ₂When, refracted light is parallel with optical axis, now meets：

γ₂=n θ₂- β=θ₂ (14)

Can draw：β=(n-1) θ₂ (15)

I.e.：θ₂=α=θ₁ (16)

Thus can obtain, when two axicon lens base angles meet 0 ° of ＜ θ₁＜ θ₂During the relation that 5 ° of ＜, emergent ray can intersect at optical axis On a bit, at this point i.e. be capable of achieving 0 side-play amount irradiation.

If summit is D in the second plano-convex axicon lens 2, radius is a, and bottom width is b, and outgoing beam is E with optical axes crosspoint, with the Two plano-convex axicon lens, 2 front surface intersection point is F, crosses F and is vertical line GF, γ to optical axis₃For the angle of GF and EF, DE=d is made₂, by geometry Relation can be obtained：

GF=r₁+CF·sinβ₁ (18)

GD=GFtan θ₂ (19)

d₂=DE=GE-GD=GF (tan γ₃-tanθ₂) (20)

The normal and 2 front surface of the second plano-convex axicon lens for extending incident ray meets at M, can be obtained by geometrical relationship：

CM=b+atan θ₂-r₁·tanθ₂ (21)

Arrangement can be obtained：

By γ₂=n θ₂- β,β=(n-1) θ₁, β=n β₁Substitute into：

By small angle approximation, can abbreviation be：

The internal diameter r of annular radiation source₂Meet with the distance between the second plano-convex axicon lens 2 d：

r₂=(d₂-d)·cotγ₃=(d₂-d)·cot(n-1)(θ₂-θ₁)

As shown in figure 3, for a kind of schematic diagram of spatial deviation Raman spectroscopic detection system, the detection system is mainly for danger Dangerous product are particularly liquid explosive and measure, the sour sodium of the explosive such as such as TNT, ammonium chloride, black powder, dimethylbenzene, hydrogen peroxide and The prohibited items generally containing groups such as nitro, amino, phenyl ring such as ethanol are detected.The detection device includes：Laser instrument 101st, expand device 102, axicon lens ring type laser irradiating device 103, signal collection device 104, band pass filter means 105, poly- Coke installation 106, spectrogrph 107, computer 108 and one-dimensional movement platform 1010.Axicon lens ring type laser irradiating device 103 is wrapped Include：Coaxial the first plano-convex axicon lens being placed in parallel and the second plano-convex axicon lens.The first plano-convex axicon lens and the second plano-convex cone The refractive index of lens is identical, and the conical surface direction of the conical surface of the first plano-convex axicon lens and the second plano-convex axicon lens is identical, the first plano-convex The base angle of base angle of the base angle of axicon lens less than the second plano-convex axicon lens, the first plano-convex axicon lens and the second plano-convex axicon lens is little In 5 °.

The laser that laser instrument 101 sends is injected and expands device 102, is formed swash Jing after expanding device 102 and carry out beam-expanding collimation Light light beam, laser beam incide the plane of the first plano-convex axicon lens along the optical axis direction of two plano-convex axicon lens, through cone Annular radiation source is formed after lens ring type laser irradiating device 103, by treating in the annular radiation source directive sample cell 109 Test sample product, change the distance between axicon lens ring type laser irradiating device 103 and testing sample by one-dimensional movement platform 1010, Realize that the continuous variable of annular radiation source internal diameter is adjusted.By signal collection device 104 in the center of annular radiation source After carrying out the collection of flashlight, then all kinds of spurious signals beyond band pass filter means 105 eliminate flashlight, by focusing on Device 106 is focused on the probe of spectrogrph 107, carries out spectrum analyses by computer.When annular radiation source internal diameter changes When, the relative distance between shot point and bleeding point changes, that is, realize the detection of spatial deviation Raman spectrum.

The axicon lens ring type laser irradiating device of the application and the spatial deviation Raman spectroscopic detection system with the device, The drawbacks of needing in solving prior art by moving into repeatedly, removing axicon lens to realize 0 side-play amount, it is to avoid due to repeating The irradiation non-uniformity that positioning causes.Only by the translation in one-dimensional square, you can realize spatial offset from the continuous of 0 beginning It is adjustable, the complexity of irradiation devices is not only reduced, while improve its stability, economically feasible.

Preferred embodiment of the present utility model is the foregoing is only, is merely illustrative for this utility model, and It is nonrestrictive.Those skilled in the art understanding, can be to which in the spirit and scope limited by this utility model claim Many changes are carried out, is changed, in addition it is equivalent, but fall within protection domain of the present utility model.

Claims (3)

1. a kind of axicon lens ring type laser irradiating device, when laser beam irradiates thereon, which can produce annular exposure light Source, it is characterised in which includes coaxial the first plano-convex axicon lens being placed in parallel and the second plano-convex axicon lens, first plano-convex Axicon lens is identical with the refractive index of the second plano-convex axicon lens, the conical surface of the first plano-convex axicon lens and second plano-convex The conical surface direction of axicon lens is identical, and the base angle of the first plano-convex axicon lens is less than the base angle of the second plano-convex axicon lens, institute The base angle for stating the first plano-convex axicon lens and the second plano-convex axicon lens is respectively less than 5 °.

2. a kind of axicon lens ring type laser irradiating device according to claim 1, it is characterised in that when first plano-convex The distance between axicon lens and the second plano-convex axicon lens are d₁When, the generation of the axicon lens ring type laser irradiating device 0 side-play amount exposure spots are apart from the second plano-convex axicon lens apart from d₂Meet formula：

$d_2=\[d_1\·(n-1){\mathrm{\θ}}_1-r_0+\frac{b\·{\mathrm{cot\θ}}_2+a-d_1\·(n-1){\mathrm{\θ}}_1+r_0}{(1-\frac{1}{n}){\mathrm{\θ}}_1+\cos (1-\frac{1}{n}){\mathrm{\θ}}_1\·{\mathrm{cot\θ}}_2}\·(1-\frac{1}{2}){\mathrm{\θ}}_1\]\·\cot (n-1)({\mathrm{\θ}}_2-{\mathrm{\θ}}_1)$

Wherein, n is the refractive index of the first plano-convex axicon lens and the second plano-convex axicon lens, θ₁For the base angle of the first plano-convex axicon lens, θ₂ For the base angle of the second plano-convex axicon lens, r₀It is the laser beam radius after expanding, b is the bottom width of the second plano-convex axicon lens, a For the radius of the second plano-convex axicon lens, 0 ° of ＜ θ₁＜ θ₂5 ° of ＜.

3. a kind of axicon lens ring type laser irradiating device according to claim 2, it is characterised in that when first plano-convex The distance between axicon lens and the second plano-convex axicon lens d₁When immobilizing, change 0 side-play amount exposure spots saturating with the second plano-convex cone Mirror apart from d₂, you can obtain continually varying annular radiation source, the internal diameter r of the annular radiation source₂Meet formula：

r₂=(d₂-d)·cot(n-1)(θ₂-θ₁)

Wherein, d is annular the distance between radiation source and the second plano-convex axicon lens.