Generation of coupled orbital angular momentum modes from an optical vortex parametric laser source

Area of Science:

• Optics and Photonics
• Quantum Optics

Background:

• Optical parametric oscillators (OPOs) are versatile sources for generating light at new wavelengths.
• Vortex beams carrying orbital angular momentum (OAM) offer unique properties for light-matter interactions.
• Controlling OAM modes in nonlinear optical processes is crucial for advanced applications.

Purpose of the Study:

• To demonstrate the generation of coupled OAM modes (flower/wheel modes) from a vortex-pumped OPO.
• To investigate the effect of pump source temporal coherence on OAM mode generation.
• To achieve higher-order OAM vortex signal output.

Main Methods:

• Utilized a vortex-pumped optical parametric oscillator.
• Employed pump sources with varying temporal coherence times (short and long).
• Tuned signal and idler outputs to specific wavelength ranges (745-955 nm and 1200-1855 nm).

Main Results:

• Successfully generated flower (wheel) modes, exhibiting coupled OAM.
• Achieved higher-order vortex signal output (ℓs=2-4) by using a pump source with longer coherence time.
• Obtained a maximum signal output energy of 1.2 mJ with 15.6% optical efficiency.

Conclusions:

• Temporal coherence of the pump source is a critical parameter for controlling OAM modes in vortex-pumped OPOs.
• The demonstrated method offers a pathway to generate complex OAM states for various optical applications.
• The OPO system provides efficient generation of tunable vortex beams.