Optimized optical propagation through underwater turbulence using off-axis Bessel-Gauss beam probing.

Off-axis Bessel-Gauss (BG) beams are used as a generation basis within an optical system that rapidly probes an underwater turbulent environment. Due to the rapidity of the scan, implemented using a modified Higher Order Bessel Beams Integrated with Time (HOBBIT) system, instantaneous realizations of the turbulence can be probed allowing optimal transmission paths in which the beams propagate, with minimal perturbations, through the complex turbulent environment. The results show a marked reduction in the effects of the turbulence, including over a 91% decrease in scintillation index, experienced by the beams propagated through these paths when compared to a centered on-axis BG beam.

Higher order Bessel beams integrated in time (HOBBIT) with engineered light frequencies (ELFs).

This paper presents a scheme exploiting a uniform circular frequency diverse array (UC-FDA) of optical beamlets to realize non-diffracting beams with unprecedented switching rates in orbital angular momentum (OAM). The frequency diversity property of the system is a result of using an acousto-optic deflector (AOD) to generate an array on a circle which tags each beamlet with different frequencies. The non-diffracting nature of the generated beams is examined along with the generation of arbitrary time-dependent non-diffracting amplitude structures using the local phase control inherent in the system architecture.

High data-rate communication link supported through the exploitation of optical channels in a characterized turbulent underwater environment.

Underwater turbulence presents a myriad of challenges for underwater optical systems through wavefront distortion and beam deflection. In this work, an underwater turbulence emulator is developed and thoroughly characterized to experimentally test the proposed underwater turbulence mitigation technique. This technique applies a modified HOBBIT system introduced in atmospheric turbulence to the relatively unknown underwater turbulence domain.