A method and device for obtaining a Bessel beam based on cross-phase modulation

Abstract

The invention discloses a method and device for obtaining a Bessel beam based on cross-phase modulation: step 1, focusing the modulated laser beam in a nonlinear medium; After the linear medium, make it enter the imaging device; step 3, adjust the light intensity of the modulated laser beam until an obvious central bright spot and concentric ring pattern appear on the imaging device in the far field; step 4, adjust the focal length of the focusing lens or the The position of the linear medium is the Bessel beam with different sizes of the central bright spot. The method of the invention has the advantages of simple structure, easy operation and controllable size of the central bright spot.

Description

technical field

[0001] The invention belongs to the field of nonlinear optics, in particular to a method and device for obtaining a Bessel beam based on cross-phase modulation. Background technique

[0002] In the field of optics, a Bessel beam refers to a beam whose transverse amplitude distribution satisfies the Bessel function, and its transverse light intensity distribution appears as a central bright spot and a series of concentric rings. A true Bessel beam does not undergo diffraction, that is, it can maintain its lateral light intensity distribution during its propagation, and it will restore its lateral light intensity distribution when it encounters an obstacle. It is precisely because of the unique light intensity distribution and propagation characteristics of the Bessel beam that it has very important application value in the fields of laser fine processing, optical imaging, particle manipulation, microlithography, and nonlinear optics. At present, the methods t...

Examples

Embodiment 1

[0049] Prepare the test device as follows:

[0050] There are 2 lasers, the continuously tunable ring titanium sapphire laser (Matisse TR) emits the light as the modulated laser beam; the external cavity semiconductor laser emits the light as the modulated laser beam.

[0051] Convex lens 1, focal length 500mm.

[0052] 2 half-wave plates.

[0053] Two polarizing beam-splitting cubes.

[0054] Nonlinear medium, rubidium (Rb) atomic pool.

[0055] CCD for imaging.

[0056] Such as figure 1 As shown, the specific steps of using the method of the present invention to obtain a hollow beam are as follows:

[0057] Step 1: Focus the modulated laser beam 8 emitted by the tunable annular titanium sapphire (Matisse TR) laser with the convex lens 1 to obtain a Gaussian beam with a waist spot size of 172 μm, and set the waist spot position as the coordinate origin; The Gaussian beam is focused in the nonlinear medium 4 after passing through the first half-wave plate 2 and the first...

technical field

[0001] The invention belongs to the field of nonlinear optics, in particular to a method and device for obtaining a Bessel beam based on cross-phase modulation. Background technique

[0002] In the field of optics, a Bessel beam refers to a beam whose transverse amplitude distribution satisfies the Bessel function, and its transverse light intensity distribution appears as a central bright spot and a series of concentric rings. A true Bessel beam does not undergo diffraction, that is, it can maintain its lateral light intensity distribution during its propagation, and it will restore its lateral light intensity distribution when it encounters an obstacle. It is precisely because of the unique light intensity distribution and propagation characteristics of the Bessel beam that it has very important application value in the fields of laser fine processing, optical imaging, particle manipulation, microlithography, and nonlinear optics. At present, the methods t...

Examples

Embodiment 1

[0049] Prepare the test device as follows:

[0050] There are 2 lasers, the continuously tunable ring titanium sapphire laser (Matisse TR) emits the light as the modulated laser beam; the external cavity semiconductor laser emits the light as the modulated laser beam.

[0051] Convex lens 1, focal length 500mm.

[0052] 2 half-wave plates.

[0053] Two polarizing beam-splitting cubes.

[0054] Nonlinear medium, rubidium (Rb) atomic pool.

[0055] CCD for imaging.

[0056] Such as figure 1 As shown, the specific steps of using the method of the present invention to obtain a hollow beam are as follows:

[0057] Step 1: Focus the modulated laser beam 8 emitted by the tunable annular titanium sapphire (Matisse TR) laser with the convex lens 1 to obtain a Gaussian beam with a waist spot size of 172 μm, and set the waist spot position as the coordinate origin; The Gaussian beam is focused in the nonlinear medium 4 after passing through the first half-wave plate 2 and the first...

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