CN103336366A - Device capable of generating uniform linear laser beams based on high-numerical aperture cylindrical lens focusing - Google Patents

Abstract

The invention relates to a device capable of generating uniform linear laser beams based on high-numerical aperture cylindrical lens focusing. The device is composed of a linear polarization laser light source, a spherical lens assembly, a rectangular aperture, a 1/2 wave plate, a discontinuous wave plate and a high-numerical aperture cylindrical lens. Light beams generated by the linear polarization laser light source are subjected to beam expansion and collimation which are performed by the spherical lens assembly, and then, rectangular linearly polarized light which is almost uniform and is arranged at the center of a light spot selectively passes through the rectangular aperture; the rectangular linearly polarized light emitted by the rectangular aperture passes through the 1/2 wave plate, and then, passes through or does not pass through the discontinuous wave plate; and after that, the rectangular linearly polarized light is focused by the high-numerical aperture cylindrical lens, and the uniform linear laser beams are generated at a focal plane. With the device which is of structural simplicity adopted, under the situations that the discontinuous wave plate is used or not used, the uniform linear laser beams of which the center is flat-topped can be obtained at the focal plane through simply rotating the 1/2 wave plate and changing the numerical aperture of the high-numerical aperture cylindrical lens, wherein the uniform linear laser beams can be used for linear scanning microscopic imaging, and micro-nano materials processing and detection.

Description

Focus on the device that produces the uniform line laser beam based on high-NA post lens

Technical field

The invention belongs to the laser beam shaping field, be specifically related to a kind of device that produces the uniform line laser beam that focuses on based on high-NA post lens.

Background technology

Uniform line throws light on the processing of online scanning microscopy imaging, micro Nano material and the field detected has a wide range of applications.In order to satisfy the requirement of above-mentioned use, the uniform line illumination of generation need have strong light intensity, good light intensity uniformity and superfine size.Traditional lamp is carried out the uniform line illumination that beam shaping obtains be difficult to realize simultaneously above-mentioned requirements, and along with the appearance of high brightness laser light source, by laser beam being carried out the uniform line illumination that optical shaping can obtain to meet the demands.Be generally the uniform line laser beam that obtains flat-top, the beam shaping system need adopt complicated structure, and the use of non-spherical lens makes it expensive.

Summary of the invention

At the defective that exists in the above-mentioned prior art or deficiency, the objective of the invention is to, provide a kind of and focus on the device that produces the uniform line laser beam based on high-NA post lens, this device can produce superfine uniform line laser beam.

In order to realize above-mentioned task, the present invention takes following technical solution:

A kind of device based on high-NA post lens focusing generation uniform line laser beam is characterized in that: be made up of linearly polarized laser light source, globe lens group, rectangular aperture, 1/2nd wave plates, discontinuous wave plate and high-NA post lens;

The light beam that the linearly polarized laser light source produces, behind globe lens group beam-expanding collimation, by rectangular aperture choose the spot center part almost uniformly the rectangular lines polarized light pass through; The rectangular lines polarized light that penetrates from rectangular aperture is through 1/2nd wave plates, then through or behind discontinuous wave plate, focus on the focal plane place by high-NA post lens and produce the uniform line laser beam.

The device that produces the uniform line laser beam that focuses on based on high-NA post lens of the present invention, simple in structure, using or do not using under the situation of discontinuous wave plate, can produce superfine uniform line laser beam by the polarization direction of change rectangular lines polarized light and the numerical aperture of high-NA post lens; Thin uniform line laser beam can be used for line sweep micro-imaging, micro Nano material processing and detects.

Description of drawings

Fig. 1 is the apparatus structure synoptic diagram that produces the uniform line laser beam that focuses on based on high-NA post lens of the present invention;

Fig. 2 (a) rectangular lines polarized light field when not using discontinuous wave plate distributes; (b) be rectangle TEM behind the discontinuous wave plate of use ₀₁The linearly polarized light field distribution;

Fig. 3 is discontinuous wave chip architecture synoptic diagram;

Fig. 4 (a) is rectangular lines polarized light (φ ₀=28.1 °) focus on the back at the even surface of intensity distribution of the center flat-top of focal plane place generation through the aplanasia post lens of numerical aperture NA=1; (b) for producing similar even light distribution, φ ₀With the satisfied graph of relation of NA;

Fig. 5 (a) is rectangle TEM ₀₁Linearly polarized light (φ ₀=32 °) focus on the back at the even surface of intensity distribution of the center flat-top of focal plane place generation through the aplanasia post lens of numerical aperture NA=1; (b) for producing similar even light distribution, φ ₀With the satisfied graph of relation of NA.

The present invention is described in further detail below in conjunction with drawings and Examples.

Embodiment

Embodiment 1:

As shown in Figure 1, present embodiment provides a kind of device based on high-NA post lens focusing generation uniform line laser beam, is made up of linearly polarized laser light source 1, globe lens group 2, rectangular aperture 3,1/2nd wave plates 4 and high-NA post lens 6;

The light beam that linearly polarized laser light source 1 produces, behind globe lens group 2 beam-expanding collimations by rectangular aperture 3 choose the spot center part almost uniformly the rectangular lines polarized light pass through; The rectangular lines polarized light that penetrates from rectangular aperture 3 is focused on by high-NA post lens 6 through 1/2nd wave plates, 4 backs, produces the uniform line laser beam at the focal plane place.

In the present embodiment, linearly polarized laser light source 1 is gas laser light source, semiconductor laser light resource, all-solid state laser light source or fiber laser light source.

Globe lens group 2 is made up of little focal length globe lens and long-focus globe lens, and its medium and small focal length globe lens is placed on the front, and the long-focus globe lens is placed on the back of little focal length globe lens, is used for the light beam that linearly polarized laser light source 1 produces is carried out beam-expanding collimation.

Rectangular aperture 3 be used for choosing the spot center part almost uniformly the rectangular lines polarized light pass through.

/ 2nd wave plates 4 are used for regulating the polarization direction of rectangular lines polarized light.

The bus of high-NA post lens 6 is parallel with the x axle.

The rectangular lines polarized light field distributes shown in Fig. 2 (a), and polarization direction and y axle clamp angle are φ ₀

The focusing based on high-NA post lens of present embodiment produces the device of uniform line laser beam and realizes that principle is: for the linearly polarized light that high-NA post lens focus on, near the optical field distribution its focal plane need adopt the vector diffraction methods analyst,

$\stackrel{\→}{E}(y_s,z_s)=E_x{\stackrel{\→}{e}}_x+E_y{\stackrel{\→}{e}}_y+E_z{\stackrel{\→}{e}}_z,---\left(1\right)$

Y wherein _s, z _sBe the image planes rectangular coordinate system;

With

For along x, y, the unit vector of z direction.

The electric field component E of focal plane place _x, E _yAnd E _zCan be expressed as

Wherein as square position angle

θ _Max=sin ^-1(NA/n) be the integration maximum angular that post lens numerical aperture determines; N is the image planes medium refraction index; A=kf/2, k are wave vector, and f is the post focal length of lens.Relative amplitude E _{0, x}And E _{0, y}Can be expressed as

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="0"\; label="E"\; filenames="HDA00003309638400021.png,HDA00003309638400031.png"\; state="\{\{state\}\}">E</figure-callout>}}_{0,x}\left(\mathrm{\&theta;}\right)=\sin \left({\mathrm{\&phi;}}_0\right),\\ {\mathrm{<figure-callout\; id="0"\; label="E"\; filenames="HDA00003309638400021.png,HDA00003309638400031.png"\; state="\{\{state\}\}">E</figure-callout>}}_{0,y}\left(\mathrm{\&theta;}\right)=\cos \left({\mathrm{\&phi;}}_0\right).\end{array}\right.---\left(4\right)$

According to equation (2) and (4) as can be seen, by suitable selection φ ₀Combination can realize that the uniform line of center flat-top focuses on light distribution with NA.

Be rectangular lines polarized light (φ as Fig. 4 (a) ₀=28.1 °) focus on the back at the even surface of intensity distribution of the center flat-top of focal plane place generation through the aplanasia post lens of numerical aperture NA=1, Ix, Iy, Iz represent x respectively, y, z electric field component light intensity; (b) for producing similar even light distribution, φ ₀With the satisfied graph of relation of NA.

Embodiment 2:

As shown in Figure 1, in the light path shown in the embodiment 1, add a discontinuous wave plate 5, convert the rectangular lines polarized light to rectangle TEM ₀₁Linearly polarized light, rectangle TEM ₀₁Linearly polarized light focuses on focal plane 7 places through aplanasia high-NA post lens 6, and other conditions of present embodiment are with embodiment 1.

In the present embodiment, exist certain height poor between the two halves of discontinuous wave plate 5, so that produce the relative phase difference of π between the light beam two halves, thereby convert the rectangular lines polarized light to rectangle TEM ₀₁The line polarisation; And the separatrix between discontinuous wave plate 5 two halves is parallel with the x axle.Discontinuous wave plate 5 structural representations as shown in Figure 3.

Rectangle TEM ₀₁The linearly polarized light field distribution is shown in Fig. 2 (b), and polarization direction and y axle clamp angle are φ ₀, two parts field orientation is opposite up and down.

The focusing based on high-NA post lens of present embodiment produces the device of uniform line laser beam, and it realizes that principle is similar to Example 1, the electric field component E of its focal plane place _x, E _yAnd E _zCan be expressed as:

According to equation (4) and (5) as can be seen, by suitable selection φ ₀Combination can realize the uniform line focused light light distribution of center flat-top with NA.

Be rectangle TEM as Fig. 5 (a) ₀₁Linearly polarized light (φ ₀=32 °) focus on the back at the even surface of intensity distribution of the center flat-top of focal plane place generation through the aplanasia post lens of numerical aperture NA=1, Ix, Iy, Iz represent x respectively, y, z electric field component light intensity; (b) for producing similar even light distribution, φ ₀With the satisfied graph of relation of NA.

Claims (7)

1. device that focus on to produce the uniform line laser beam based on high-NA post lens, it is characterized in that, formed by linearly polarized laser light source (1), globe lens group (2), rectangular aperture (3), 1/2nd wave plates (4), discontinuous wave plate (5) and high-NA post lens (6);

The light beam that linearly polarized laser light source (1) produces, behind globe lens group (2) beam-expanding collimation, by rectangular aperture (3) choose the spot center part almost uniformly the rectangular lines polarized light pass through; The rectangular lines polarized light that penetrates from rectangular aperture (3) is through 1/2nd wave plates (4), then through or behind discontinuous wave plate (5), focus on focal plane (7) by high-NA post lens (6) and locate to produce the uniform line laser beam.

2. the device that focus on to produce the uniform line laser beam based on high-NA post lens as claimed in claim 1, it is characterized in that described linearly polarized laser light source (1) is gas laser light source, semiconductor laser light resource, all-solid state laser light source or fiber laser light source.

3. the device based on high-NA post lens focusing generation uniform line laser beam as claimed in claim 1 is characterized in that described globe lens group (2) is made up of little focal length globe lens and long-focus globe lens.

4. the device based on high-NA post lens focusing generation uniform line laser beam as claimed in claim 1 is characterized in that described 1/2nd wave plates (4) are used for regulating the polarization direction of rectangular lines polarized light.

5. the device that focus on to produce the uniform line laser beam based on high-NA post lens as claimed in claim 1, it is characterized in that, exist certain height poor between described discontinuous wave plate (5) two halves, so that produce the relative phase difference of π between the light beam two halves, thereby convert the rectangular lines polarized light to rectangle TEM01 linearly polarized light; And the separatrix between discontinuous wave plate (5) two halves is parallel with the x axle.

6. as claim 1 or 5 described devices based on high-NA post lens focusing generation uniform line laser beam, it is characterized in that described discontinuous wave plate (5) can be selected to use or do not use.

7. the device based on high-NA post lens focusing generation uniform line laser beam as claimed in claim 5 is characterized in that described rectangle TEM01 linearly polarized light focuses on focal plane (7) through aplanasia high-NA post lens (6) and locates; And the bus of high-NA post lens (6) is parallel with the x axle.

Images