Orbital angular momentum exchange in a picosecond optical parametric oscillator

Area of Science:

• Nonlinear Optics
• Quantum Optics
• Laser Physics

Background:

• Ultrafast optical parametric oscillators (OPOs) are crucial for generating tunable laser light.
• Orbital Angular Momentum (OAM) in light beams offers unique properties for optical applications.
• Controlled OAM generation in ultrafast lasers is an active area of research.

Purpose of the Study:

• To investigate and demonstrate the controlled generation of orbital angular momentum (OAM) modes in an ultrafast optical parametric oscillator (OPO).
• To explore the exchange and transfer of OAM between interacting beams within the OPO cavity.
• To achieve tunable OAM modes in the generated signal and idler beams.

Main Methods:

• Utilized a singly-resonant OPO synchronously pumped by a picosecond vortex beam (532 nm).
• Employed a frequency-doubled Yb-fiber laser as the pump source.
• Controlled cavity loss and spatial overlap to manipulate OAM mode generation.

Main Results:

• Successfully transferred pump OAM to the non-resonant idler beam (tunable 1109-1209 nm) with OAM orders up to l=3.
• Generated specific signal and idler OAM mode combinations, e.g., (0,2), (1,1), (0,3), (1,2).
• Achieved maximum idler output powers of 202 mW (l=1), 113 mW (l=2), and 57 mW (l=3) with 1 W pump power.

Conclusions:

• This work presents the first report on the controlled generation of OAM modes from an ultrafast OPO.
• Demonstrated the feasibility of OAM mode manipulation within an ultrafast OPO system.
• Highlights the potential of ultrafast OPOs for generating tailored OAM beams.