Octave-wide supercontinuum generation of light-carrying orbital angular momentum

Area of Science:

• Nonlinear optics
• Optical fiber communications
• Quantum optics

Background:

• Nonlinear frequency generation of light-carrying orbital angular momentum (OAM) is crucial for applications like super-resolution microscopy and space-division multiplexing.
• In bulk media, nonlinear coupling of OAM beams is often indistinguishable, leading to outputs that do not conserve OAM during processes like supercontinuum generation.

Purpose of the Study:

• To demonstrate nonlinear frequency generation in OAM modes with controlled properties.
• To achieve on-demand, frequency-diverse optical vortices with preserved OAM states.

Main Methods:

• Utilized specially designed optical fibers with tailored group velocities for OAM modes.
• Leveraged spin-orbit interactions in fibers to induce effective index and group velocity splitting.
• Engineered nonlinear mode selectivity for high spatial mode purity.

Main Results:

• Demonstrated Raman solitons in OAM modes.
• Generated the first octave-spanning supercontinuum (630 nm to 1430 nm) in a single polarization and OAM state.
• Ensured all nonlinearly generated frequencies resided in modes with high spatial mode purity.

Conclusions:

• Specially designed optical fibers enable controlled nonlinear frequency generation and manipulation of OAM beams.
• This work overcomes limitations of bulk media, paving the way for advanced optical vortex applications.
• The demonstrated supercontinuum and Raman solitons in OAM modes offer unprecedented control over frequency-diverse optical vortices.