Adjustable Bessel beam generating device and design method of high-end ring Dammam grating thereof

A circular Damman grating and Bessel beam technology, which is applied in the field of Bessel beam generation devices, can solve the problems of Bessel beam adjustment difficulties and the need to readjust the system optical path.

Active Publication Date: 2015-09-16
SHANGHAI INST OF OPTICS & FINE MECHANICS CHINESE ACAD OF SCI
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Problems solved by technology

If it is necessary to change the lateral resolution or axial depth of focus of the resulting Bessel beam, a new annular Damman grating must be replaced, result

Method used

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  • Adjustable Bessel beam generating device and design method of high-end ring Dammam grating thereof
  • Adjustable Bessel beam generating device and design method of high-end ring Dammam grating thereof
  • Adjustable Bessel beam generating device and design method of high-end ring Dammam grating thereof

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Embodiment

[0055] Taking the 3rd-order circular Damman grating as an example below, for its working wavelength (800nm), the present invention is based on the specific embodiment of the adjustable Bessel beam generating device of the high-order circular Damman grating:

[0056] The circular Damman grating used is a third-order, binary π-phase, multi-period circular Damman grating. Refractive index n of fused silica glass at 800nm 0 =1.453, the corresponding phase depth is h=0.8 / (2×(1.453-1))=0.88 μm. The normalized radius of the phase turning point corresponding to the multi-period third-order circular Damman grating is {r n} = {0.1501, 0.4389, 0.5000, 0.5611, 0.8499}. It is assumed that the laser used is a semiconductor fiber coupled output laser with a wavelength of 800 nm. The numerical aperture of the fiber coupling output mirror is NA=0.25, and the focal length is 11 mm; the focal length of the collimating lens 4 is 30 mm. The spot size incident on the circular Damman grating is ...

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Abstract

The invention discloses an adjustable Bessel beam generating device and the design method of a high-end ring Dammam grating thereof. The adjustable Bessel beam generating device orderly comprises an optical fiber coupling output laser, a coupling output optical fiber, an optical fiber coupling output mirror, a collimator lens, the high-end ring Dammam grating, a first lens, an annular amplitude filter sheet, a circular turntable and a second lens 9. The annular amplitude filter sheet is arranged on the circular turntable. The circular turntable can freely rotate about the central axis. According to the invention, the lateral resolution and the axial focus depth of a generated Bessel beam can be adjusted to some extent, and the adjustable Bessel beam generating device can be widely used for large depth imaging, laser particle capturing, a self-focusing servo system and other occasions.

Description

technical field [0001] The invention relates to a Bessel beam generating device, in particular to a design method for an adjustable Bessel beam generating device and a high-order circular Damman grating. Background technique [0002] The Bessel beam is a non-diffracting beam with high lateral resolution and large axial depth of focus. It has been widely used in laser processing, optical storage, imaging with large depth of field, laser trapping and particle acceleration. Annular Damman grating is a device that introduces the idea of ​​Damman phase encoding into annular grating to generate a series of equal-intensity annular light spots on the Fourier transform plane. In 2003, Zhou Changhe et al first proposed the concept of circular Damman grating [Optics Letters 28 2174 (2003)]. Subsequently, the circular Damman grating was further developed, from the initial non-periodic structure to the radial periodic structure, and the circular Damman grating has been widely used in va...

Claims

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Application Information

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IPC IPC(8): G02B5/18G02B27/00
Inventor 余俊杰周常河贾伟卢彦聪项长铖
Owner SHANGHAI INST OF OPTICS & FINE MECHANICS CHINESE ACAD OF SCI
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