Teaching optics with a focus on innovation Douglas Martin Lawrence University
Our goal and conceit Teach students to be more innovative Prepare students for research in a modern optics lab. Aprile Lab, Columbia Martin Lab, Lawrence while covering the content in a traditional junior/senior optics course
teaching students to innovate... in optics! the application of new ideas or approaches to the improvement of products or processes that draw upon important antecedents and provide value to society
teaching students to innovate... select target (what to innovate) acquire (or have) expertise generate ideas prune ideas and plan prototype refine and revise in optics! provided, except for final project canned labs brainstorming/ Deep Dive (IDEO) pre lab activities build with modular optics equipment
Our Modular Optics Equipment
Optics in 10 weeks Monday Wednesday Friday 70+ minute lecture 3+ hour lab 3+ hour lab (with candy) students grouped into teams of 2 or 3 8 canned labs designed to build expertise ~2 hour pre lab for each lab session 4 two session challenge labs 1 four session student designed project
The Canned Labs 1. Refraction and imaging 2. Reflection and beam steering 3. Collimation and beam profiling 4. Aberrations: spherical and chromatic 5. Characterization of polarized light 6. Interference phenomena 7. Michelson interferometer 8. Diffraction and spatial filtering
Canned Lab Example: Aberrations Prelab: 10. Draw a ray diagram showing how the following patterns arisefor a lens with spherical aberration. Have the knife edge cut off exactly the bottom half of the rays. marginal ray paraxial ray mid focus In lab:
Mini challenge: Aberration 15 30 minute innovation challenge at the end of each canned lab. Aberration mini challenge: Make a circle of light with one hemisphere red, the other hemisphere green.
The Challenge Labs 1. Build a Telescope: Long distance imaging, capture, and resolution characterization 2. White Light Interferometry 3. Interferometric Metrology Challenge 4. Optical Computing (Fourier Optics and Spatial Filtering) used Spatial Light Modulators (SLM) *** Workshop 16 on Thursday. *** 5. Final Projects (student determined)
Challenge Lab Example: Build a Telescope Your primary goal is to form a legible image on the webcam of the smallest font text possible (24 pt, 12 pt, 9 pt, 6 pt, 3 pt) on the paper attached to the whiteboard ~ 4 m away from your bench. Once you have reached the limit you think possible, characterize the magnification of your telescope, and spherical and chromatic aberration in the system.
Telescope Challenge Outcome Anecdotal: Students took enormous satisfaction designing, building, and characterizing their telescopes Telescope with the best resolution: Galilean telescope, with large parabolic mirror.
Challenge Lab Example: Interferometer Measurement Challenge Students instructed to choose a measurement, and used the interferometer that will best suit their experiment. Possible Interferometer Choice Mach Zender Sagnac Wedge plate Scatter Fabry Perot Twyman Green = (Michelson) Possible Measurement Choices Index of refraction of air or another gas (as a function of temperature or something else?) Thermal expansion of a metal copper, aluminum, etc. Radius of curvature of a spherical mirror The wavelength difference of two closely spaced spectral lines (such as D1 and D2 of sodium) Optical quality of a prism Thickness of a glass plate of known index of refraction
Interferometer Challenge Outcomes
Challenge Example: Optical Computing with SLM A SLM is a liquid crystal device that is in essence a variable wave plate. It has 1024x768 pixels, each of which can retard a wave by 0-π radians The two challenges were: (i) Extract a kitty from a hexagonal cage. (ii) Create a dynamic filter that transitions white light to a single color
Final Projects imaging by different animal eye apertures holographic interferometry solar spectroscopy external cavity modes optical tweezers aberration minimized camera
Selected comments from Student Evaluations Labs were extraordinarily successful, frustrating, enjoyable, frustrating, and learning centered. Fantastic. One of the best classes I've taken... but group work was hard. The instructors practiced the rare ability of supporting students without giving us the answers. We tried to work on problems from a theoretical perspective on the pre lab assignments, but the concepts didn't click until trying it out in lab. The build up from canned labs to challenges with more and more independence was great.
Lessons Learned Successful Not as successful... Students learned a lot of optics and practical techniques Prelab handouts successfully prepared students for canned labs (without need of extensive lecture) Prelabs for challenge labs: plans and troubleshooting brainstorms, with prioritization Being visual an excellent means of communication & building a framework Students report success in optics research labs (Arizona Optical Sciences, Colorado, Brandeis,...) Course is a large time commitment (for profs and students) Students did not fail early enough! (They did not buy into the idea of prototyping) Students had a hard time stepping back and analyzing WHY something was an issue/problem (what is the underlying constraint?)
Outlook for the Lab Co Curriculum Lab based optics can provide both content theory (from imaging through Fourier Optics and diffraction) practice (optomechanics assembly and manipulation) and process design build refine and repeat
Acknowledgements Shannon O Leary (now at Lewis & Clark) NSF CCLI (now TUES) program for funding LU physics faculty and students Plug: Shannon is the moderator for the Optics & Laser breakout discussion Friday at 8:45 am