Control the orbital angular momentum in third-harmonic generation using quasi-phase-matching

Area of Science:

• Nonlinear optics
• Quantum optics
• Photonics

Background:

• Photon orbital angular momentum (OAM) manipulation is crucial for advanced optical technologies.
• Nonlinear optical interactions offer pathways for controlling light properties.
• Previous methods for OAM control are limited.

Purpose of the Study:

• To propose and demonstrate a novel scheme for controlling the OAM of a third harmonic wave.
• To utilize cascaded second-order nonlinear processes for OAM transfer.
• To experimentally validate the proposed OAM control mechanism.

Main Methods:

• Frequency doubling of a Gaussian beam in a nonlinear optical crystal.
• Sum frequency mixing between a second harmonic wave and a Laguerre-Gaussian-like fundamental wave.
• Utilizing a tandem periodically-poled LiTaO3 optical superlattice for nonlinear interactions.

Main Results:

• Successfully generated a third harmonic wave with controlled OAM.
• The generated third harmonic wave inherited the OAM of the fundamental Laguerre-Gaussian-like wave.
• Experimental results align with theoretical predictions, confirming the OAM control scheme.

Conclusions:

• The proposed scheme effectively controls the OAM of the third harmonic wave.
• Cascaded nonlinear processes provide a viable method for OAM manipulation.
• This technique has potential applications in optical communications and quantum information processing.