Design of Freeform Surface Lens for Shaping Divergent Laser Beam

Yameng, 彭亚蒙 Peng; Zhouping, 苏宙平 Su

doi:10.3788/aos201636.0522003

Cited by 5 publications

(3 citation statements)

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“…In order to realize beam shaping, many beam shaping methods have been proposed. Laser beam shaping methods include cutting aperture beam shaping, diffractive optical element beam shaping [10], birefringent lens beam shaping, liquid crystal spatial modulator beam shaping [11], freeform surfaces beam shaping [12][13], etc. Compared with other methods, the freeform beam shaping method has higher design freedom, simple design, simple optical system structure and easy installation and adjustment.…”

Section: Introductionmentioning

confidence: 99%

Design of annular beam shaping system based on freeform surface

Xing

Ma²,

Chen³

2023

International Conference on Optical Technology, Semiconductor Materials, and Devices (OTSMD 2022)

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Laser is widely used in manufacturing, information transmission, biotechnology and other fields,but these fields often need the input beam with specific intensity distribution, and the Gaussian beam needs beam shaping to achieve the required illuminance distribution.Annular flattned beam has great demand in satellite communication, laser high-speed welding and other fields.The existing beam shaping system needs to compensate off-axis aberration and chromatic aberration, and its design process and system structure are complex.In this paper, we propose a design method of coaxial reflection annular beam shaping system based on geometric optics principle.Through ray mapping method to establish a mapping relationship,through geometrical optics principle to derive the freeform surface equation.We constructed the beam shaping system of the double freeform mirror, which can realize the annular flattened beam with a uniformity of 96.35%.Compared with the existing beam shaping system, the coaxial double reflection system has fewer optical elements, more compact structure, less calculation of optical element structure, and avoids off-axis aberration and chromatic aberration under the condition of similar shaping uniformity.

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Section: Introductionmentioning

confidence: 99%

Design of annular beam shaping system based on freeform surface

Xing

Ma²,

Chen³

2023

International Conference on Optical Technology, Semiconductor Materials, and Devices (OTSMD 2022)

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“…However, for the applications of optical therapy, laser projection [4], and lithography [5], etc., it is necessary to homogenize Gaussian beam into a flat-topped beam. Aspheric lens group method [6][7][8], free-form lens method [9][10][11][12], diffracted optical elements (DOEs) [13][14][15], and microlens array (MLA) [16][17][18][19] are usually used to achieve laser beam homogenization. For the aspheric lens group method, the energy distribution of Gaussian beam is spatially modulated to form a uniform distribution in a specific position.…”

Section: Introductionmentioning

confidence: 99%

Integrated Double-Sided Random Microlens Array Used for Laser Beam Homogenization

Wei

Xue

et al. 2021

Micromachines

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Double microlens arrays (MLAs) in series can be used to divide and superpose laser beam so as to achieve a homogenized spot. However, for laser beam homogenization with high coherence, the periodic lattice distribution in the homogenized spot will be generated due to the periodicity of the traditional MLA, which greatly reduces the uniformity of the homogenized spot. To solve this problem, a monolithic and highly integrated double-sided random microlens array (D-rMLA) is proposed for the purpose of achieving laser beam homogenization. The periodicity of the MLA is disturbed by the closely arranged microlens structures with random apertures. And the random speckle field is achieved to improve the uniformity of the homogenized spot by the superposition of the divided sub-beams. In addition, the double-sided exposure technique is proposed to prepare the rMLA on both sides of the same substrate with high precision alignment to form an integrated D-rMLA structure, which avoids the strict alignment problem in the installation process of traditional discrete MLAs. Then the laser beam homogenization experiments have been carried out by using the prepared D-rMLA structure. The laser beam homogenized spots of different wavelengths have been tested, including the wavelengths of 650 nm (R), 532 nm (G), and 405 nm (B). The experimental results show that the uniformity of the RGB homogenized spots is about 91%, 89%, and 90%. And the energy utilization rate is about 89%, 87%, 86%, respectively. Hence, the prepared structure has high laser beam homogenization ability and energy utilization rate, which is suitable for wide wavelength regime.

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“…However, the intensity distribution of a laser is usually in a Gaussian profile, which is always required to be converted into a flat-top profile so as to achieve the desired effect, e.g., laser welding [9,10], an optical system of exposure machine [11], laser drilling [12,13] and laser projection [14,15]. There are some methods to achieve beam homogenization, such as an aspheric lens group [16][17][18], free-form lens [19][20][21], diffractive optical element (DOE) [22][23][24] and microlens array (MLA) [25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Random Microlens Array for Laser Beam Homogenization with High Efficiency

et al. 2020

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The miniaturized and integrated microlens array (MLA) can effectively achieve the beam homogenization, compactness and miniaturization of laser systems. When the high-coherence laser beam is homogenized by means of using the MLA, interference fringes will occur in the homogenized light spot due to the periodicity of the MLA, which seriously affects the uniformity of the homogenized light spot. To solve this problem, a novel random microlens array (rMLA) structure was proposed for the purpose of achieving beam homogenization. The coherence in the homogenization process is suppressed by means of breaking the periodicity of the MLA. The homogenized light spot with a high energy utilization is then obtained accordingly. In the fabrication process, a clever method of combining chemical etching with lithography technology is performed to fabricate a honeycomb rMLA and a rectangular rMLA. The experimental results show that the energy utilization rate of the two types of the rMLAs is about 90%, and the uniformity of the homogenized light spots generated by the honeycomb rMLA and the rectangular rMLA are more than 80% and 85%, respectively. Meanwhile, fully cost-effective fabrication is possible to be realized.

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Design of Freeform Surface Lens for Shaping Divergent Laser Beam

Cited by 5 publications

References 0 publications

Design of annular beam shaping system based on freeform surface

Design of annular beam shaping system based on freeform surface

Integrated Double-Sided Random Microlens Array Used for Laser Beam Homogenization

Fabrication of Random Microlens Array for Laser Beam Homogenization with High Efficiency

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