Laboratory Courses as the Foundation / Pillars of Optomechnical Engineering

Jonathan Ellis

Micro-LAM, Inc., USA

Learning practical concepts requires getting outside one’s comfort zones. Often, learning by doing, such as in laboratory classes, can cement concepts that are first introduced in lecture courses. However, a concept need not necessarily be taught in a lecture first or from first principles. Rather, the application of concept often necessitates understanding broad concepts that are related and can only be fully understood by doing. Two examples of this are learning in laboratory classes and learning cross-disciplines such as optomechanical engineering.

In laboratory classes, building and aligning a simple Michelson interferometer or point source microscope using benchtop components can take hours. Those hours are not lost, rather they are used to understand mounting the optics, or the painstaking process of alignment, or the sensitivity of one degree of freedom over another. It may seem frustrating at first, but these are skills that are only fully realized by physically performing them. Similarly, immersing oneself in a new disciple can be painstaking at first. But learning and understanding a few key concepts can build a foundation for future success.

Laboratory Courses as the Foundation

Laboratory courses require more resources to educate students effectively, from equipment, software, and space to instructors, and time. Building a relatively simple optical device, a point source microscope (PSM), can be used to impart many optical concepts and can be accomplished with generic, off-the-shelf components and several key laboratory devices.

The first step in building a PSM is beam collimation from a simple fiber source. This can be accomplished with a shear plate, which also demonstrates interference. The focus through the beam is found by placing a mirror at the measurement point, demonstrating retroreflection.

The reflected beam through the beamsplitter can then be collimated again with the shear plate by correctly aligning the mirror to the measurement point. Lastly, a tube lens is aligned to achieve the smallest focal point.

This can be easily expanded or modified for other concepts. Adding a mirror on the beamsplitter and removing the tube lens changes this to an interferometer. And each of these systems can be reinforced via first-principles calculations and then modeling and analysis can be performed with optical design software!

Pillars of Optomechanical Engineering

Summarizing another discipline, mechanical engineering, such that optical engineers and scientists can utilize key information, is a difficult endeavor. Nomenclature, variable notation, and common abbreviations are some of the issues faced when crossing disciplines. For example, the acronym TIR to many in the optics industry is total internal reflection. But TIR can also readily refer to total indicator runout for lens centering, metrology, and manufacturing. Understanding the language across disciplines is the first step to branching out to new fields.

For optomechanical engineering, many concepts are required to truly master the discipline. However, many of those concepts can be distilled into three different concepts that form the pillars of optomechanical engineering and affect optical and mechanical components alike.