The diverse range of Navy activities both above and below the sea and on land is divided into components known as System Commands, or SYSCOMs. This issue includes papers from researchers represented by two of the Navy SYSCOMs: The Naval Sea Systems Command (NAVSEA) and the Naval Air Systems Command (NAVAIR). NAVSEA supports the engineering, building, purchasing, and maintenance of the Navy’s ships and submarines and their combat systems, while NAVAIR provides full life-cycle support of naval aviation aircraft, weapons and systems operated by sailors and marines. Within each SYSCOM are the Warfare Centers, which provide the capabilities, facilities (labs and ranges) and specialized expertise necessary for conducting research, development, test and evaluation (RDT&E) to address current and future Navy needs. Scientists and engineers at the Warfare Centers conduct cutting edge research to develop the next generation of sensors, platforms, and systems for the Navy of tomorrow.

Funding for research at the Navy SYSCOM laboratories is provided by a variety of external and internal sources. The Office of Naval Research, which is itself a Navy SYSCOM, funds research though individual research grants or via the In-house Laboratory Independent Research (ILIR) or Independent Applied Research (IAR) programs. Another source of funding is through the Naval Innovative Science and Engineering (NISE)/Section 219 program, which supports internal basic and applied research, workforce development, and technology transitions. Strategic collaborations between the SYSCOM laboratories, academia, and industry are also often leveraged to combine resources for solving complex Navy problems. This is evident in several of the contributed papers where academic researchers are included as co-authors.

The focus of the contributed papers is on optics-related research and covers various aspects of optical systems for Navy applications. The source of light is a vital component of an optical system and either originates from the sun for passive sensors or from a laser for actively-illuminated scenes. Lasers are being used in many Navy applications due to their unique characteristics, including high directionality, narrow spectral content, and wide information bandwidth. One such application is described in the contributed paper “Raman Spectroscopy in the presence of stray resonant light,” where the authors discuss using lasers to drive stimulated Raman transitions for atom optics.

Characterizing new laser materials for challenging applications is another ongoing area of research in the Navy laboratories. This is the subject of “Transmittance Derived Line Width and Line Shift in Polycrystalline Nd:YAG,” where line width measurements for both single crystal and polycrystalline Nd:YAG are presented.

Before the light is detected, it must travel though an intervening medium, where it can be scattered and absorbed. “Propagation of modulated optical beams carrying orbital angular momentum (OAM) in turbid water” details the results of experiments conducted to evaluate the effect of murky water on the propagation of an encoded laser beam. After propagating through the environment, the optical signal must be recovered by a receiver that has both high sensitivity and wide dynamic range. A technique using a resonant optical cavity to enhance detector efficiency is described in the contributed paper entitled “Ray tracing analysis of a two-dimensional rectangular optical cavity for enhancing detector efficiency,” while “Simplified weighting function for high dynamic rage video frame formation” discusses different image formation techniques to improve receiver dynamic range.

The final step is to process the electrical signal generated by the optical detector. In some applications, the goal is to separate a desired signal component from unwanted clutter. In the paper entitled “Independent component analysis for enhancement of an FMCW optical ranging technique in turbid waters,” a processing technique is described that uses the statistical differences between target and backscatter return signals to improve optical ranging in water. Signal processing techniques developed for other types of sensors, such as radar, can also be applied to optical systems. “Digital passband processing of wideband modulated optical signals for enhanced underwater imaging” details the use of radar modulation, demodulation, and signal processing schemes for improving the performance of underwater optical imaging systems.

While this feature issue covers many of the pertinent components of an optical system, it highlights only a small portion of the optics research being performed at the Navy SYSCOMs. However, the objective of this feature was to enlighten the readers to the variety and high quality of research being conducted in the Navy laboratories. It is my hope that this goal has been met and will pave the way for similar features in the future.