CN109581558B - A kind of preparation method of multifocal diffractive element and multifocal diffractive element - Google Patents
A kind of preparation method of multifocal diffractive element and multifocal diffractive element Download PDFInfo
- Publication number
- CN109581558B CN109581558B CN201811597506.XA CN201811597506A CN109581558B CN 109581558 B CN109581558 B CN 109581558B CN 201811597506 A CN201811597506 A CN 201811597506A CN 109581558 B CN109581558 B CN 109581558B
- Authority
- CN
- China
- Prior art keywords
- diffractive element
- multifocal
- multifocal diffractive
- step etching
- focal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/18—Diffraction gratings
- G02B5/1847—Manufacturing methods
- G02B5/1857—Manufacturing methods using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/0012—Optical design, e.g. procedures, algorithms, optimisation routines
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Diffracting Gratings Or Hologram Optical Elements (AREA)
- Eyeglasses (AREA)
Abstract
本申请涉及一种多焦点衍射元件的制备方法及多焦点衍射元件，包括：获取多焦点衍射元件的基本参数；根据所述基本参数计算各个焦段对应的台阶刻蚀深度；根据所述台阶刻蚀深度进行仿真实验论证以得到所述多焦点衍射元件。本申请提供的多焦点衍射元件减小了多焦点衍射元件的尺寸，避免了多个光学元件之间的对准问题，使其使用场景更加灵活广泛。上述多焦点衍射元件能够产生等距的多焦点，各焦点间的峰值能量均匀性、点扩散函数一致性都能通过优化得到很好的结果，可以作为高精度微纳加工系统中的重要分光元件，并且在某些特定成像光学系统中对于增大焦深有着十分重要的作用。
The present application relates to a method for preparing a multifocal diffractive element and a multifocal diffractive element, including: acquiring basic parameters of the multifocal diffractive element; calculating the step etching depth corresponding to each focal length according to the basic parameters; In-depth simulation experiments are demonstrated to obtain the multifocal diffractive element. The multi-focal diffractive element provided by the present application reduces the size of the multi-focal diffractive element, avoids the alignment problem between multiple optical elements, and enables more flexible and extensive use scenarios. The above-mentioned multifocal diffractive element can generate equidistant multifocal points, and the peak energy uniformity and point spread function consistency between each focus can be optimized to obtain good results, and can be used as an important spectroscopic element in high-precision micro-nano processing systems. , and plays a very important role in increasing the depth of focus in some specific imaging optical systems.
Description
Technical Field
The present disclosure relates to the field of optical elements, and in particular, to a method for manufacturing a multifocal diffractive element and a multifocal diffractive element.
Background
The special optical property of the multi-focus optical element enables a beam of parallel light to be converged at a plurality of axial focuses simultaneously, so that the multi-focus optical element is widely applied to various modern optical processing and imaging systems. For example, when a femtosecond laser cuts a thick transparent material, because the cutting and separation of the transparent material by using a single laser focus is greatly influenced by the thickness of the material, the trend of thermal cracks induced at the laser focus in the thickness direction is not controlled along with the increase of the thickness of the transparent material, so that the surface shape of a cut section is irregular, even the surface is broken, and the like, the physical properties of the surface of the material are seriously influenced, and the application of the femtosecond laser cutting in the thick transparent material is limited. The laser beams are converged into a plurality of focuses in the axial direction by the multi-focus optical element and are uniformly distributed at different positions in the thickness direction of the transparent material, so that a cutting surface with high flatness is obtained; for example, the characteristics of the compound eye structure, such as high sensitivity to a moving object, are widely concerned and researched due to the special performance of a wide field of view, and in order to expand the focal depth of the bionic compound eye structure during imaging, the bionic compound eye structure can be realized by using a multifocal optical lens array.
Conventional multifocal optical elements generally have two implementations. One type is a fold-back optic, as shown in fig. 1. Common forms of such optical elements are: the multi-focus optical device has larger volume, is inconvenient for adjusting a light path and greatly limits the application scene; and the optical elements in the system are usually made into hollow structures, which is inconvenient to process. The second is to use diffractive optics to achieve multiple focal points, but such conventional multiple focal point diffractive elements have three major disadvantages: the conventional multifocal diffractive element is a diffractive-refractive hybrid optical device consisting of two parts: a conventional convex lens and diffractive optical element. This approach also limits the use of its functionality to some extent, for example, when used in a bionic compound eye structure, the alignment of two optical elements becomes an urgent problem to be solved. ② such conventional diffractive multifocal optical elements cannot form equidistant multifocal lenses due to problems inherent to the design. And thirdly, point spread functions of all the focuses are inconsistent, so that the peak energy intensity and the full width at half maximum of all the focuses are inconsistent, and the imaging quality of all the focal planes is influenced.
Disclosure of Invention
In view of the above, the present application provides a method for manufacturing a multifocal diffractive element and a multifocal diffractive element, so as to solve the above problems.
A first aspect of embodiments of the present application provides a method for manufacturing a multifocal diffractive element, the method comprising:
acquiring basic parameters of a multifocal diffraction element, wherein multifocal is a focus with equal step width;
calculating the step etching depth corresponding to each focal segment according to the basic parameters;
and carrying out simulation experiment demonstration according to the step etching depth to obtain the multifocal diffraction element.
Optionally, the calculating step etching depths corresponding to the focal segments according to the basic parameters includes:
planning and calculating the step etching position and the step etching depth to be etched according to the number of focuses of the multifocal diffraction element;
and integrating the step etching depths, and sequencing the step etching depths corresponding to the radial widths in sequence according to the focal sections so as to finally obtain the ordered step etching depths.
Optionally, the step etching depth is calculated by the following formula:
wherein HiTo etch depth, fiIn order to design the focal length, n is the refractive index of the material, r is the radial distance of each step of the diffraction element, lambda is the design wavelength, and m is the number of focuses.
Optionally, the performing simulation experiment demonstration according to the step etching depth to obtain the multifocal diffractive element includes:
after step etching is carried out according to the step etching depth, whether the peak energy of each focus is consistent with the half-width height of the corresponding energy peak is verified;
if the difference is not consistent, the difference between the peak value energy of each focus and the half width height of the corresponding energy peak is adjusted to be within a specified range by increasing or decreasing the number of steps corresponding to the focus section, and finally the multifocal diffraction element is obtained.
Optionally, the adjusting the difference of the peak energy of each focus to the half width height of the energy peak corresponding to the peak energy by increasing or decreasing the number of steps of the corresponding focus segment to a specified range includes:
changing the utilization rate of each focus by increasing or decreasing the number of steps corresponding to the focus section;
and adjusting the consistency of point spread function areas at each focus by changing the step width corresponding to each focus section, so that the difference between the peak energy of each focus and the half width height of the energy peak corresponding to the peak energy is within a specified range.
A second aspect of embodiments of the present application provides a multifocal diffractive element produced by a method described in any one of the above methods for producing a multifocal diffractive element.
The invention has the beneficial effects that: in the method for manufacturing the multifocal diffraction element, the multifocal diffraction element is provided with a plurality of focuses, so that multifocal distribution can be realized by using only one diffraction element without a focusing lens. Compared with the traditional multifocal diffraction element, the multifocal diffraction element provided by the application further reduces the size of the multifocal diffraction element, and avoids the alignment problem among a plurality of optical elements, so that the use scene is more flexible and wide; secondly, the multifocal diffraction element provided by the application can generate equidistant multifocal, and peak energy uniformity and point spread function consistency among focuses can obtain good results through optimization, so that the multifocal diffraction element can be used as an important light splitting element in a high-precision micro-nano processing system and has an important function of increasing the focal depth in some specific imaging optical systems.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
FIG. 1 is a multifocal diffractive element provided in the prior art;
FIG. 2 is a schematic flow chart illustrating a method for fabricating a multifocal diffractive element according to an embodiment of the present invention;
FIG. 3 is a schematic view of a step etch depth design according to an embodiment of the present disclosure;
FIG. 4 is a diagram illustrating a difference between peak energy distributions of a multifocal diffractive element and a diffractive element fabricated by a conventional method according to an embodiment of the present invention;
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.
Fig. 2 illustrates a method for manufacturing a multifocal diffractive element provided herein, which is detailed below: the preparation method comprises the following steps:
step S21, obtaining basic parameters of a multifocal diffractive element, wherein the multifocal is a focus with an equal step width.
In the embodiments provided in the present application, when manufacturing the multifocal diffractive element, basic parameters of the multifocal diffractive element, such as the number of focuses, the focal length of each focus, the initial step width, the number of step cycles, and the like, are first determined. The plurality of focuses in the multifocal diffractive element provided by the present application are focuses of equal step width.
And step S22, calculating the step etching depth corresponding to each focal segment according to the basic parameters.
Optionally, the calculating step etching depths corresponding to the focal segments according to the basic parameters includes:
planning and calculating the step etching position and the step etching depth to be etched according to the number of focuses of the multifocal diffraction element;
and integrating the step etching depths, and sequencing the step etching depths corresponding to the radial widths in sequence according to the focal sections so as to finally obtain the ordered step etching depths.
Optionally, the step etching depth is calculated by the following formula:
wherein HiTo etch depth, fiIn order to design the focal length, n is the refractive index of the material, r is the radial distance of each step of the diffraction element, lambda is the design wavelength, and m is the number of focuses.
The design of the diffraction element with the equal step width is carried out on each focus, and the step height required to be etched is calculated. As shown in fig. 2.
The calculation formula is as follows:
wherein HiTo etch depth, fiIn order to design the focal length, n is the refractive index of the material, r is the radial distance of each step of the diffraction element, lambda is the design wavelength, and m is the number of focuses. Therefore, the step etching depth corresponding to each focal segment is obtained.
And then integrating the step etching depth, and sequentially arranging the etching depths corresponding to the radial widths according to the focal segments, wherein the final etching depth is as shown in figure 2.
H＝[h1 h2 ... hi h1 h2 ... hi ... h1 h2 ... hi]
And step S23, performing simulation experiment demonstration according to the step etching depth to obtain the multifocal diffraction element.
Optionally, the performing simulation experiment demonstration according to the step etching depth to obtain the multifocal diffractive element includes: and verifying whether the peak energy of each focus is consistent with the half-width height of the corresponding energy peak after step etching is carried out according to the step etching depth.
If the difference is not consistent, the difference between the peak value energy of each focus and the half width height of the corresponding energy peak is adjusted to be within a specified range by increasing or decreasing the number of steps corresponding to the focus section, and finally the multifocal diffraction element is obtained.
Optionally, the adjusting the difference of the peak energy of each focus to the half width height of the energy peak corresponding to the peak energy by increasing or decreasing the number of steps of the corresponding focus segment to a specified range includes:
changing the utilization rate of each focus by increasing or decreasing the number of steps corresponding to the focus section;
and adjusting the consistency of point spread function areas at each focus by changing the step width corresponding to each focus section, so that the difference between the peak energy of each focus and the half width height of the energy peak corresponding to the peak energy is within a specified range.
Specifically, the peak energy and the half-width height of each focus of the multifocal diffractive element prepared by the above process are not uniform, which is caused by the fact that the effective R/# of each focus is not the same. The peak energy intensity and the half-width height of each focus are required to be consistent through a subsequent optimization step.
The specific optimization method comprises the following steps:
according to the formula
The number of steps corresponding to each focal section is increased or decreased to ensure that the R/# corresponding to each focal point is equal, so that the energy utilization rate of each focal point is changed, then the width of the step corresponding to each focal section is changed to enable the point spread functions at each focal point to be consistent, finally the peak energy and the full width at half maximum of each focal point are kept similar, and the process needs to be iterated for multiple times. The specific flow of design and optimization is shown in fig. 3.
As shown in fig. 4, the bifocal diffractive element was designed for focal lengths of 40mm and 50mm, respectively, both 2.2mm in diameter using the conventional multifocal diffractive element design method and the design method of the present invention. The peak energy (normalization) of the bifocal optical element designed by the traditional design method at two focuses is 1/0.64 respectively, and the full width at half maximum (normalization) is 0.63/1 respectively; the peak energy (normalization) at the two focuses of the bifocal diffractive element of the present invention is 1/0.97, and the full width at half maximum (normalization) is 0.89/1. The uniformity of the peak energy is improved by 51 percent, and the uniformity of the full width at half maximum is improved by 41 percent. It can be seen that the advantages of the multifocal diffractive element design method of the present invention are significant.
In the method for manufacturing the multifocal diffraction element, the multifocal diffraction element is provided with a plurality of focuses, so that multifocal distribution can be realized by using only one diffraction element without a focusing lens. Compared with the traditional multifocal diffraction element, the multifocal diffraction element provided by the application further reduces the size of the multifocal diffraction element, and avoids the alignment problem among a plurality of optical elements, so that the use scene is more flexible and wide; secondly, the multifocal diffraction element provided by the application can generate equidistant multifocal, and peak energy uniformity and point spread function consistency among focuses can obtain good results through optimization, so that the multifocal diffraction element can be used as an important light splitting element in a high-precision micro-nano processing system and has an important function of increasing the focal depth in some specific imaging optical systems.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (4)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811597506.XA CN109581558B (en) | 2018-12-26 | 2018-12-26 | A kind of preparation method of multifocal diffractive element and multifocal diffractive element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811597506.XA CN109581558B (en) | 2018-12-26 | 2018-12-26 | A kind of preparation method of multifocal diffractive element and multifocal diffractive element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109581558A CN109581558A (en) | 2019-04-05 |
| CN109581558B true CN109581558B (en) | 2021-01-15 |
Family
ID=65931856
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811597506.XA Active CN109581558B (en) | 2018-12-26 | 2018-12-26 | A kind of preparation method of multifocal diffractive element and multifocal diffractive element |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109581558B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110989062B (en) * | 2019-12-17 | 2021-05-04 | 中国科学院长春光学精密机械与物理研究所 | A kind of multifocal optical element and design method thereof |
| CN111007664A (en) * | 2019-12-18 | 2020-04-14 | 中国科学院光电技术研究所 | Design method of diffractive optical element with high diffraction efficiency and low speckle noise |
| CN111673269B (en) * | 2020-07-01 | 2022-05-31 | 中国工程物理研究院激光聚变研究中心 | Focal spot rapid movement regulation and control system based on surface type reflector set and regulation and control method thereof |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2632707Y (en) * | 2003-01-20 | 2004-08-11 | 杨国光 | Microoptical glass lens |
| US8556417B2 (en) * | 2012-02-02 | 2013-10-15 | Novartis Ag | Apodized hybrid diffractive-refractive IOL for pseudo-accommodation |
| CN107976732B (en) * | 2017-11-15 | 2019-11-05 | 中国科学院长春光学精密机械与物理研究所 | A kind of change step diffraction element and preparation method thereof |
-
2018
- 2018-12-26 CN CN201811597506.XA patent/CN109581558B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN109581558A (en) | 2019-04-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109581558B (en) | A kind of preparation method of multifocal diffractive element and multifocal diffractive element | |
| CN107315206B (en) | Surpass the efficient infrared optics lens and preparation method thereof of surface texture based on all dielectric | |
| Žukauskas et al. | Improvement of the Fabrication Accuracy of Fiber Tip Microoptical Components via Mode Field Expansion. | |
| CN104297925B (en) | A Design Method of Refractive-Diffractive Hybrid Elements Realizing Long Focal Depth of Femtosecond Laser | |
| CN112859206B (en) | Preparation method of all-dielectric superlens for forming flat top light by Gaussian polishing | |
| CN112059404B (en) | Method and system for processing ultrafine single crystal fiber cladding | |
| TW200903585A (en) | Parameter adjustment method, semiconductor device manufacturing method, and recording medium | |
| CN112327397A (en) | A method for fabricating large-area volume gratings by femtosecond plasma grating direct writing | |
| CN105171235A (en) | Bi-focus laser micro-processing device and processing method thereof | |
| US20150253504A1 (en) | Phase and amplitude control for optical fiber output | |
| CN105116474B (en) | The flat axicon lens of 1-D photon crystal that a kind of column vector beam Diode laser sub-wavelength focuses on | |
| CN106019429B (en) | A kind of 1-D photon crystal plano-concave mirror of column vector beam sub-wavelength multiple-point focusing | |
| CN112068238A (en) | A single stress element fiber chirped fiber Bragg grating and its preparation method | |
| Luo et al. | Fabrication of parabolic cylindrical microlens array by shaped femtosecond laser | |
| CN107643596B (en) | Binary zone plate type diffraction axicon lens system and long focal depth imaging method thereof | |
| CN109633822A (en) | A kind of optical fiber bessel beam generator and preparation method thereof | |
| CN217571287U (en) | Bessel beam lens for laser cutting | |
| CN108535865A (en) | A kind of negative refraction grating plano-concave mirror design method that focal length is controllable | |
| Fu et al. | Microprismatic Fresnel lens for formation of uniform light circle | |
| CN111965746B (en) | An all-dielectric plano-concave focusing lens with hollow secondary focus suppression | |
| CN111650688A (en) | A special optical fiber micro-combination lens | |
| TWI230806B (en) | GRIN lenses, devices and methods of manufacture | |
| JP2020518021A (en) | Lens system used with high laser power density scanning system | |
| CN109773330B (en) | Laser output system based on homogenizing device and calculating method | |
| KR101470204B1 (en) | Optical system for splitting beam focus into multifocal |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |