2.1

Research Experiences for Undergraduates

During each summer of our LESA partnership we provided a Research Experiences for Undergraduates (REU) program at Rose-Hulman. Besides Rose-Hulman undergraduate participants, we developed collaborations with Norfolk State University and Morgan State University to recruit students to participate in the REU program. In addition, during four summers, we included a high school student from the local area. The high school students are designated by LESA as Young Scholars, a high school student participating in a paid internship with LESA working on a LESA research project funded either by LESA direct funding or through an associated project.

The students worked on teams (two to three students) on a specific research project that we mentored and guided through an eight week summer period. A project title and a short description of the project was provided to each team on the first day of the program. Within the first week, the teams were required to conduct fundamental research on the topic, read relevant articles, and provide a list of equipment needed to conduct their research or project. By the beginning of the second week, the teams were required to submit a project plan (usually in the form of a Gantt chart) and give a presentation about their project to the mentors and the other teams. At the beginning of each week, each team was required to give a 15 minute oral presentation and submit a memo report about plans, activities to date, and goals for the next week. The summer program culminated in a final group presentation and a poster session.

Project examples included: “Solar energy harvesting for LED lighting”, “Study properties of LEDs with temperature and current”, “Environmental control of LED lighting”, “Holographic optical elements for use in lighting”, “Driving LED Light with Solar Panels”, “Feasibility Study of Data Communication Using Visible Light Communication (VLC)”, and “Color Detection and Color Temperature”. One example research project was, “Study of white-light LEDs optical characteristics at high currents”. This project involved driving an LED beyond its rated current and examining the effect of the spectral output all the way to LED component failure. The students developed a test bed for driving the LED and measuring the spectra and total output flux with increasing current. The detection system was comprised of a 12 inch integrating sphere (StellarNet IS12) and a StellarNet BLACK-Comet spectrometer. Figure 1 shows the spectrum of a white-light LED component for two different drive currents. As the current is increased within the range of the LED’s rated forward current (35 mA), the output increases as expected. However, as current is increased beyond the rated forward current the output spectrum changes and the output flux decreases as shown in Fig. 2. The total flux output as a function of input current is shown in Fig. 3. Students recommended that the thermal properties of the LEDs should be measured simultaneously in a future project.

Figure 1.

Spectra of white light LED for two currents below the rated forward current of 35 mA.

Figure 2.

Four spectral scans of white light LED for drive currents of 82 mA, 95 mA, 115 mA, and 125 mA. The rated forward current is 35 mA.

Figure 3.

Total flux output from a white light LED as a function of drive current, up to and beyond the 35 mA rated forward current.

In addition to the research project each team was charged with producing an educational outreach video. More detail about these videos will be described later. We also incorporated a team building/creativity activity for all teams. One example was the development of a lighted sign for the student study area, they call the “h-bar”. The students developed several concepts and with minimal faculty input chose a design for prototyping. The design for the display was inspired by REU research projects involving scattering of light in asymmetric waveguides and coupling of high brightness LEDs to structures. Figure 4 shows the lighted prototype display.

Figure 4.

Prototype lighted display sign produced by a student group

2.2

High School Research and Mentoring

Besides the Young Scholars program, we also partnered with Oak Lawn Community High School, Oak Lawn, Illinois (located in the Chicago Metropolitan area), through our connection and collaboration with a Rose-Hulman alum who is a science teacher at the school. His interest was mainly focused on providing a solid research experience for several of his students during the summer as part of a summer enrichment course.

The first suitable project chosen after several discussions with the high school teacher was to have the Oak Lawn group of students investigate a prototype LED light that was to be charged during the day with a solar panel and used for reading at night. This light source prototype was developed by an REU team sponsored by the Faculty without Borders group at Rose-Hulman to be implemented either in Kenya or Ghana. The high school students divided into teams to investigate a particular aspect of the development and testing resulting in studies on, “Battery Charge Time Field Test”, “Optimal Power Field Study”, and “Solar Panel Alignment Field Study”. Their results were provided to the Faculty without Borders for further studies and expansion of the prototype. The students were mentored by the REU students through a skype meeting once a week. The work of the high school group was integrated with the REU projects at the end of summer poster session.

A second project example given to the high school group was to investigate the illumination pattern of various luminaires. As part of the research outreach, we donated two lighting kits to the school containing a white light LED as the main source, two reflectors, and three types of condensing optics along with the necessary optical power meters, lux meters, and individual detector components. For example, students were able to learn about illumination concepts and test the illumination level as a function of distance for each light configuration and compare the data to the ideal inverse square law. They also measured light profiles as viewed on an illuminated flat wall. The learning outcomes, set by their high school teacher in collaboration with the professors from Rose-Hulman, included defining experimental tests, collecting appropriate data, and fitting the data to a theory.

3.1

K-12 Teacher Workshops and Presentations

One of the challenges associated with optics education is the pipeline of high school students interested in majoring in optical sciences and engineering. Consequently, we developed a work shop targeting high school science teachers so that they might gain some knowledge of optics and to make them aware of educational and professional opportunities for their students. A one-day workshop was organized with the goal to introduce the science and technology of modern solid state lighting and its applications including LEDs, basics of light, light measurement, light propagation, and color to secondary high school teachers. The workshop format included interactive lectures with group discussions, and hands on experiments using LED sources, lasers, and holograms. Each participant received materials to use in their classroom so that they can further develop age-appropriate activities that support and enhance the STEM (Science, Technology, Math and Engineering) curricula at their school.

Using our one-day workshop as a basis, we also ran several half-day workshops in partnership with Vigo County School Corporation (VCSC), and the Rose-Hulman supported program Portal Resource for Indiana Science and Mathematics (PRISM) for middle school teachers. [7] The program provides tools for teachers to integrate STEM concepts into their classroom instruction. The theme of their summer work is on energy conservation and lighting efficiency fit in well with the program. Workshop topics and activities included: Lighting History and Lighting Evolution, Understanding Light, Spectra, and LEDs, Light Measurements and Human Perception, Comparing Light Sources through Spectra. The major hands-on activity done by the teachers was to build their own holographic grating spectrograph.

In addition, several one-hour presentations were made on “Lighting, LEDs, and Energy Conservation” for selected high school teachers through the Duke Energy Sustainable Energy Institute on the Rose-Hulman Institute of Technology campus. The purpose of this institute is to provide the teachers a true “boot camp experience” in sustainable energies combining academic professional development on the Rose-Hulman campus with vocational experience through site visits to some alternative energy providers in Indiana.

3.2

Students-teaching-students: You-tube videos

As mentioned previously, besides project work and research, each REU student team developed a video tutorial on some aspect of lighting, optics, and optical engineering associated with their project. The runtime of each video varied between 6-12 minutes. Examples of video tutorial topics include: “Light modulation and communication”, “Solar cells”, “PN junctions”, “Radiometry and photometry terms and definitions”, and “Light source characteristics”. Some of the videos are available for viewing on the LESA youtube channel. [6,8]

3.3

Community Outreach

During two summers we had our REU student teams pool together and develop/modify an exhibit at the local Terre Haute Children’s Museum as part of their team building experience. The museum staff was especially interested in ways to improve the quality of the appearance and lighting of one of their displays. The team visited the museum, observed how children interacted with various displays and proposed changes in one of the existing displays. The exhibit is entitled “Be and Architect”. The student team recommended adding interactive and appealing elements such as: 1) Adjustment to make floor plans interchangeable, 2) Add multiple floor plans, 3) Improve attention and appeal, and 4) Make exhibit more interactive. The lighting of the floor plan was improved with LEDs embedded around the perimeter to index the interchangeable floor plans. Figure 5 shows an image of the completed display housed at the museum.

Figure 5.

Photograph of the enhanced museum interactive display.