Customized optical bottle beams based on dual diffraction-free beams

Optical bottle beams exhibit a periodic cosine distribution along the axial direction. It has found extensive applications in areas such as optical trapping, optical tweezers, and guidance of biological cells. However, the current methods employed for generating such cosine light fields lack flexibility in controlling the period and phase, thus failing to achieve desired customization. This paper presents a novel approach for generating customized cosine light fields based on dual diffractionfree beams. The first step involves defining the desired cosine distribution light field. Subsequently, using the annular aperture method, multiple diffraction-free Bessel beams with different axial wave vectors are generated, and their superposition approximates the desired cosine light field. By modifying the phase and period of the desired cosine light field, adjustments can be made to the radius and width of the annular aperture, thus easily obtaining a customized cosine light field. The feasibility of the method was validated through rigorous mathematical analysis, and its effectiveness is demonstrated through experimental verification. This method is expected to propel further applications of optical bottle beams in areas including atomic trapping, optical modulation, and guidance of biological cells.