Optical OAM tweezer based on graded-index multimode fibers

Area of Science:

• Optics and Photonics
• Fiber Optics
• Optical Tweezers

Background:

• Orbital Angular Momentum (OAM) beams offer unique properties for optical manipulation.
• Existing methods for generating and focusing OAM beams in fiber optics can be limited.
• Few-mode fibers (FMF) and graded-index multimode fibers (GIMF) are key components in advanced fiber optics.

Purpose of the Study:

• To propose and investigate a novel fiber-optic probe for generating focused OAM beams.
• To analyze the focusing properties of OAM modes within a GIMF section of the probe.
• To explore the potential of this probe for optical fiber tweezer applications.

Main Methods:

• Fabrication of a fiber-optic probe by fusing a GIMF section onto an FMF.
• Launching OAM modes guided by the FMF into the GIMF section.
• Analyzing beam propagation trajectory, intensity, and phase distributions within the GIMF.

Main Results:

• A focused OAM beam profile was successfully obtained by optimizing the GIMF length.
• The study identified an optimal GIMF length for a maximum working distance.
• A trade-off between beam size and working distance was observed, crucial for tweezer applications.

Conclusions:

• The proposed fiber-optic probe effectively generates focused OAM beams.
• The findings provide insights into the focusing characteristics of OAM modes in GIMF.
• This technology holds promise for enhancing the flexibility and efficiency of optical fiber tweezers.