CN107024760A - A kind of transmission-type light splitting focusing system for VUV LASER - Google Patents
A kind of transmission-type light splitting focusing system for VUV LASER Download PDFInfo
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- CN107024760A CN107024760A CN201710265572.6A CN201710265572A CN107024760A CN 107024760 A CN107024760 A CN 107024760A CN 201710265572 A CN201710265572 A CN 201710265572A CN 107024760 A CN107024760 A CN 107024760A
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- 230000003287 optical effect Effects 0.000 claims abstract description 12
- 230000004075 alteration Effects 0.000 abstract description 6
- 238000005516 engineering process Methods 0.000 abstract description 5
- PQXKHYXIUOZZFA-UHFFFAOYSA-M lithium fluoride Chemical compound [Li+].[F-] PQXKHYXIUOZZFA-UHFFFAOYSA-M 0.000 description 4
- ORUIBWPALBXDOA-UHFFFAOYSA-L magnesium fluoride Chemical compound [F-].[F-].[Mg+2] ORUIBWPALBXDOA-UHFFFAOYSA-L 0.000 description 4
- 229910001635 magnesium fluoride Inorganic materials 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000003384 imaging method Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000009738 saturating Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000003670 easy-to-clean Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000001819 mass spectrum Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 239000002086 nanomaterial Substances 0.000 description 1
- 238000006303 photolysis reaction Methods 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 238000002310 reflectometry Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
Classifications
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
- G02B19/0004—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed
- G02B19/0009—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed having refractive surfaces only
- G02B19/0014—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed having refractive surfaces only at least one surface having optical power
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
- G02B19/0033—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use
- G02B19/0095—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with ultraviolet radiation
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
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Abstract
A kind of transmission-type light splitting focusing system for VUV LASER proposed by the present invention, belongs to light beam light splitting focusing technology field, and the system is made up of three pieces or four pieces of convex lens and a diaphragm, and each convex lens and diaphragm are each perpendicular to light path and common optical axis is set；Wherein, the first convex lens, the second convex lens are in tandem in diaphragm the same side, and remaining convex lens is located at diaphragm opposite side.VUV LASER (VUV) light source that the system is produced to four-wave mixing carries out light splitting and focusing, and the light splitting rate to fundamental frequency light reaches more than 99.99%, and total transmitance of VUV light (125nm 150nm) can reach more than 10%.When focusing on, also spherical aberration can be offset using High-precision aspheric convex lens, the system is reached diffraction limit, so as to realize that sub-micron hot spot is focused on.
Description
Technical field
The invention belongs to light beam light splitting focusing technology field, more particularly to a kind of transmission-type for VUV LASER point
Light focusing system.
Background technology
High-intensity vacuum Ultra-Violet Laser (VUV, wave-length coverage 120-150nm) can be produced with four wave mixing technology.This swashs
The features such as radiant has high photon energy height, laser rays width, energy density and the small angle of divergence, is widely used in atom
The fields such as the measurement of molecular-excited state level structure, molecular reaction dynamics and mass spectrum imaging.Due to VUV LASER wavelength
It is short, it is possible to provide the other spatial discrimination of submicron order --- VUV light can focus to a diameter of 100nm hot spot in theory.Therefore,
VUV light is to the imaging biological cells of submicron order, and Micro-Structure Analysis of nano material etc. has far-reaching significance.
Four wave mixing technology is based on nonlinear optics principle, by input light (i.e. fundamental frequency light, including ultraviolet light, visible ray)
A part mixing medium in be converted to VUV light after, remaining fundamental frequency light can jointly be exported with VUV light.VUV wavelength is compared with fundamental frequency
Light is short, and photon energy is high compared with fundamental frequency light, but resulting VUV light intensity only has 1 the percent or smaller of fundamental frequency light.By
The fundamental frequency light of high intensity is also mixed with output light, if VUV light is not separated with the fundamental frequency light of the high intensity, it will damage is tested
Sample, or cover the effect of VUV light.Accordingly, it would be desirable to which VUV light and fundamental frequency light are separated.
VUV light and fundamental frequency light separation are typically subjected to light splitting and focusing respectively using two contained optics.Light splitting
Routine techniques is first to be separated the VUV light and fundamental frequency light in output light using prism or grating.This method make use of rib
Mirror or grating have the property of different refraction or angle of diffraction to the light of different wave length, but the VUV light road of outgoing changes direction,
Considerably increase the difficulty of experimental provision and stably use.
One of prism splitter system of document report (D.Riedel, Appl.Phys.A 69,375-380,1999) light splitting
Realized and focused on by simple lens again afterwards.Output light is changed by the direction of propagation after prism.The light deviation angle of different wave length
Degree is different, so as to realize light splitting.Not on an axis, using can be very inconvenient for Visible optical trains.
Focusing system currently used for VUV light can be using the reflection type of focusing.Reflective focus lamp has the excellent of no color differnece
Point；But cost is high, volume is big, and reflection plated film damage threshold is low.In addition, photodissociation chemical reaction in surface can generate dirt in optical surface
Layer is contaminated, reflectivity can be reduced with the working time, cause the loss of VUV light by force；And reflection plating Membrane cleaning is difficult.Particularly it is used for height
During intensity VUV light, the above mentioned problem that reflective focusing system is present can be protruded more.
To sum up, it yet there are no the transmission-type light splitting focusing system for high-intensity vacuum Ultra-Violet Laser.
The content of the invention
The invention aims to overcome the weak point of prior art there is provided a kind of for the saturating of VUV LASER
Penetrate formula light splitting focusing system.The system can use as little as three lens to reach the mesh that light splitting simultaneously and the nearly diffraction limit of sub-micron are focused on
's.
A kind of transmission-type light splitting focusing system for VUV LASER proposed by the present invention, including three pieces of convex lens and
One diaphragm, each convex lens and diaphragm are each perpendicular to light path and common optical axis is set；Wherein, before the first convex lens, the second convex lens
After be arranged in diaphragm the same side, the 3rd convex lens are located at diaphragm opposite side；
Make the distance between the distance between first and second convex lens, the second convex lens and diaphragm, diaphragm and the 3rd convex
The distance between lens are respectively L1、L2、L3, first, second, third convex lens are made in the focal length of VUV LASER wave band
Respectively f1、f2、f3, then the parameter of each element meet below equation：
1.5×(f1+f2) ＞ L1＞ f1+f2 (1)
L1＞ 2f1 (2)
f2≥f1 (3)
L3＞ f3 (5-1)
The operating distance WD of 3rd convex lens is calculated according to formula (6)：
Another transmission-type light splitting focusing system for VUV LASER proposed by the present invention, including four pieces of convex lens
With a diaphragm, each convex lens and diaphragm are each perpendicular to light path and common optical axis is set；Wherein, the first convex lens, the second convex lens
In tandem in diaphragm the same side, the 3rd convex lens, the 4th convex lens are in tandem in diaphragm opposite side；
Make the distance between the distance between first and second convex lens, the second convex lens and diaphragm, diaphragm and the 3rd convex
The distance between lens are respectively L1、L2、L3, make first, second, third and the 4th convex lens in VUV LASER wave band
Focal length be respectively f1、f2、f3、f4, then the parameter of each element meet below equation：
1.5×(f1+f2) ＞ L1＞ f1+f2 (1)
L1＞ 2f1 (2)
f2≥f1 (3)
L3=f3(5-2)；
4th convex lens are arranged on the 3rd lens rear any place, and the operating distance of the 4th convex lens is equal to the lens
Focal length f4。
The center-hole diameter of the diaphragm is 1-50 μm.
The features of the present invention and beneficial effect are：System architecture is simple, and cost is low, small volume, light path coaxial, optical surface
Damage threshold is high, pollutes easy to clean.The optics member for VUV light wave band is made of magnesium fluoride and lithium fluoride etc. by the present invention
Part, light splitting and focusing are carried out with minimum three pieces of spheres or aspherical convex lens to the VUV light source that four-wave mixing is produced.To fundamental frequency light
Light splitting rate reach more than 99.99%, total transmitance of VUV light (125nm-150nm) can reach more than 10%.When focusing on,
Coordinate non-spherical lens to offset spherical aberration, the system is reached diffraction limit, so as to realize that sub-micron diffraction limited spot is focused on.
Brief description of the drawings
Fig. 1 is a kind of light channel structure schematic diagram of transmission-type light splitting focusing system proposed by the present invention.
Fig. 2 is the light channel structure schematic diagram of another transmission-type light splitting focusing system proposed by the present invention.
Embodiment
The present invention is described in further detail below in conjunction with the drawings and specific embodiments：
The present invention proposes a kind of transmission-type light splitting focusing system for VUV LASER, by three pieces of convex lens and one
Diaphragm is constituted, and overall structure is as shown in figure 1, each convex lens are made of magnesium fluoride or lithium fluoride, and each convex lens and diaphragm hang down
Directly in light path and common optical axis setting；Wherein, the first convex lens 1, the second convex lens 2 are in tandem in the same side of diaphragm 5, and the 3rd is convex
Lens 3 are located at the opposite side of diaphragm 5.It regard the output light obtained through four-wave mixing as the incident light of this light splitting focusing system, incidence
VUV LASER of the light after first, second convex lens in the incident light converges and passes through the centre bore of diaphragm 5, fundamental frequency light
Because convex lens dispersion is blocked by diaphragm 5；VUV LASER is focused by the 3rd convex lens.
The distance of the setting of each element is as follows：
Make the distance between the distance between first and second convex lens, the second convex lens and diaphragm, diaphragm and the 3rd convex
The distance between lens are respectively L1、L2、L3, first, second, third convex lens are made in the focal length of VUV LASER wave band
Respectively f1、f2、f3, then L1、L2Meeting while below equation can reach design spectrophotometric result ensures diaphragm and first, second convex
Lens will not be damaged：
1.5×(f1+f2) ＞ L1＞ f1+f2 (1)
L1＞ 2f1 (2)
f2≥f1 (3)
The distance between second convex lens and diaphragm L2It can be determined by formula (4)：
Now spot size of the fundamental frequency light in the second convex lens position is more than 1/3W, and fundamental frequency light optical density is less than incident base
9 times of frequency light, wherein, W is unpolarized light beam diameter.As use focal length f2During longer second lens two, it can make second saturating
This optical density numerical value of fundamental frequency light diminishes at mirror.
The center-hole diameter D of the diaphragm is desirable 1-50 microns, and big I is selected according to the fire damage threshold value of tested sample
Select.Diaphragm can play a part of light splitting simultaneously and improve VUV light beam quality.The diaphragm (passes through diaphragm to the attenuation rate Q of fundamental frequency light
The ratio between light energy and incident light gross energy of centre bore, the bigger spectrophotometric result of attenuation rate is better), it can be calculated with following formula：Q=1-
(D/W)2.When unpolarized light beam is a diameter of 5 millimeters, attenuation rate is between 99.99% to 99.99999%.Although diaphragm center
The smaller spectrophotometric result of bore dia is better, but the adjustment accuracy requirement of stop position can accordingly be increased.
In order to ensure that light beam is converged behind the 3rd convex lens 3, the 3rd convex lens are to diaphragm apart from L3And the 3rd convex lens
The focal length f of mirror3It should meet：
L3＞ f3 (5-1)
The operating distance WD of 3rd convex lens should be calculated according to formula (6)：
Another transmission-type light splitting focusing system for VUV LASER proposed by the present invention, by four pieces of convex lens and
One diaphragm is constituted, and overall structure is as shown in Fig. 2 the system is on the basis of the light splitting focusing system of above-mentioned three pieces of convex lens
On, in the case of keeping the first convex lens 1, the second convex lens 2 and the parameter of diaphragm 5 and position constant, by the 3rd convex lens extremely
Diaphragm apart from L3It is adjusted to the focal length f of the 3rd convex lens3, light beam is formed collimated light after the 3rd convex lens, while
Any position at three convex lens rears is coaxially disposed the 4th convex lens 4 to realize final focusing, the work of the 4th convex lens
Distance is equal with the focal length of the 4th convex lens.Four pieces of convex lens constitute the fundamental frequency light decay rate and above-mentioned three of light splitting focusing system
The light splitting focusing system of block convex lens is consistent.Compared to three pieces convex lens light splitting focusing systems of four pieces of convex lens light splitting focusing systems
Advantage be that final VUV focal positions are adjustable, i.e. L in Fig. 24Length is desirable any on the occasion of total optical path length is more flexible.
Technical scheme is described further below by two specific embodiments.The two embodiments
With the effect for reaching light splitting, focusing on integration and light path coaxial.And simple in construction, easy to maintenance, cost is low.
Embodiment 1 is the light splitting focusing system of three pieces of convex lens, and concrete composition is as follows：
The spot diameter of incident light is 4mm in the present embodiment, and the center-hole diameter D of diaphragm is 10 μm, and the wavelength of VUV light is
125nm, the wavelength of fundamental frequency light are 255-640nm；First convex lens, the second convex lens, the focal length of the 3rd convex lens are respectively f1
=50mm, f2=80mm, f3=40mm, the distance between the first convex lens and the second convex lens L1=140mm, the second convex lens
With the distance between diaphragm L2The distance between=183mm, the 3rd convex lens and diaphragm L3=450mm, can obtain operating distance is
52mm, diffraction limited spot size is 500nm parameter.
Convex lens in the present embodiment are all made using magnesium fluoride, and the transmitance to 125nmVUV light is 13%, right
The attenuation rate of 255-640nm fundamental frequency lights is 99.93%.Now wavelength is hot spot of the 255nm UV light (ultraviolet light) at diaphragm
Size is 12mm.First convex lens, the second convex lens, the 3rd convex lens can use spherical mirror.Because spherical mirror can produce spherical aberration,
Also spherical mirror can be substituted using non-spherical lens and reduces spherical aberration, reach nearly diffraction limit performance.
Embodiment 2 is the light splitting focusing system of four pieces of convex lens, and concrete composition is as follows：
The 3rd convex lens are replaced by the convex lens that focal length is 450mm, first, second convex lens on the basis of embodiment 1
Mirror and the parameter of diaphragm and position keep constant.The effect of 3rd convex lens is to collimate the VUV light of diverging for a diameter of 20mm
Collimated light beam.Then focal length is placed on behind the 3rd convex lens 3 at 50mm for 52mm the 4th convex lens 4, you can obtain work
It is the parameter that 52mm, diffraction limited spot size are 500nm as distance.The present embodiment convex lens are all made using magnesium fluoride,
Transmitance to 125nmVUV light is that the 10%, attenuation rate to 255-640nm fundamental frequency lights is 99.93%.First, second, thirdth,
4th convex lens can use spherical mirror.Because spherical mirror can produce spherical aberration, also spherical mirror can be substituted using non-spherical lens and reduced
Spherical aberration, reaches nearly diffraction limit performance.
Claims (3)
1. a kind of transmission-type light splitting focusing system for VUV LASER, it is characterised in that including three pieces of convex lens and one
Individual diaphragm, each convex lens and diaphragm are each perpendicular to light path and common optical axis is set；Wherein, before and after the first convex lens, the second convex lens
Diaphragm the same side is arranged in, the 3rd convex lens are located at diaphragm opposite side；
Make the distance between the distance between first and second convex lens, the second convex lens and diaphragm, diaphragm and the 3rd convex lens
The distance between be respectively L1、L2、L3, make first, second, third convex lens distinguish in the focal length of VUV LASER wave band
For f1、f2、f3, then the parameter of each element meet below equation：
1.5×(f1+f2) ＞ L1＞ f1+f2 (1)
L1＞ 2f1 (2)
f2≥f1 (3)
L3＞ f3 (5-1)
The operating distance WD of 3rd convex lens is calculated according to formula (6)：
2. a kind of transmission-type light splitting focusing system for VUV LASER, it is characterised in that including four pieces of convex lens and one
Individual diaphragm, each convex lens and diaphragm are each perpendicular to light path and common optical axis is set；Wherein, before and after the first convex lens, the second convex lens
Diaphragm the same side is arranged in, the 3rd convex lens, the 4th convex lens are in tandem in diaphragm opposite side；
Make the distance between the distance between first and second convex lens, the second convex lens and diaphragm, diaphragm and the 3rd convex lens
The distance between be respectively L1、L2、L3, make first, second, third and the 4th convex lens VUV LASER wave band Jiao
Away from respectively f1、f2、f3、f4, then the parameter of each element meet below equation：
1.5×(f1+f2) ＞ L1＞ f1+f2 (1)
L1＞ 2f1 (2)
f2≥f1 (3)
L3=f3(5-2)；
4th convex lens are arranged on the 3rd lens rear any place, and the operating distance of the 4th convex lens is equal to the convex lens
Focal length f4。
3. transmission-type light splitting focusing system according to claim 1 or 2, it is characterised in that the centre bore of the diaphragm is straight
Footpath is 1-50 μm.
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| CN201710265572.6A CN107024760B (en) | 2017-04-21 | 2017-04-21 | A kind of transmission-type light splitting focusing system for VUV LASER |
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| CN201710265572.6A CN107024760B (en) | 2017-04-21 | 2017-04-21 | A kind of transmission-type light splitting focusing system for VUV LASER |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108627943A (en) * | 2018-07-06 | 2018-10-09 | 中国科学技术大学 | A kind of broadband hot spot focusing device suitable for ultra-high vacuum environment |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104104006A (en) * | 2013-04-02 | 2014-10-15 | 中国科学院理化技术研究所 | Device and method for generating high-power vacuum ultraviolet laser by direct frequency doubling |
| CN104716557A (en) * | 2013-12-13 | 2015-06-17 | 中国科学院大连化学物理研究所 | Vacuum ultraviolet laser generation device |
-
2017
- 2017-04-21 CN CN201710265572.6A patent/CN107024760B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104104006A (en) * | 2013-04-02 | 2014-10-15 | 中国科学院理化技术研究所 | Device and method for generating high-power vacuum ultraviolet laser by direct frequency doubling |
| CN104716557A (en) * | 2013-12-13 | 2015-06-17 | 中国科学院大连化学物理研究所 | Vacuum ultraviolet laser generation device |
Non-Patent Citations (2)
| Title |
|---|
| 布玛丽亚等: "VUV 超短脉冲的产生及其在超快动力学中的应用", 《原子与分子物理学报》 * |
| 陈应航等: "紫外-真空紫外光谱辐照度校准系统", 《红外与激光工程》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108627943A (en) * | 2018-07-06 | 2018-10-09 | 中国科学技术大学 | A kind of broadband hot spot focusing device suitable for ultra-high vacuum environment |
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