teaching optics with a focus on innovation - aapt
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Teaching optics with a focus on innovation
Douglas MartinLawrence University
Our goal and conceit• Teach students to be more innovative• Prepare students for research in a modern optics lab.
Martin Lab, Lawrence
while covering the content in a traditional junior/senior optics course
Aprile Lab, Columbia
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
• 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
Monday Wednesday Friday
70+ minute lecture 3+ hour lab 3+ hour lab (with candy)
The “Canned” Labs
1. Refraction and imaging2. Reflection and beam‐steering3. Collimation and beam‐profiling4. Aberrations: spherical and chromatic5. Characterization of polarized light6. Interference phenomena7. Michelson interferometer8. Diffraction and spatial filtering
Canned Lab Example: AberrationsPrelab: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.
In lab:
mid‐focusmarginal ray
paraxial ray
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 Interferometry3. Interferometric Metrology Challenge4. 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
Yourprimarygoalistoformalegibleimageonthewebcamofthesmallestfonttextpossible(24pt,12pt,9pt,6pt,3pt)onthepaperattachedtothewhiteboard~4mawayfromyourbench.
Onceyouhavereachedthelimityouthinkpossible,characterizethemagnificationofyourtelescope,andsphericalandchromaticaberrationinthesystem.
Telescope Challenge OutcomeAnecdotal: 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
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
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
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 LearnedSuccessful Not as successful. . .Students learned a lot of optics and practical techniques
Course is a large time commitment(for profs and students)
Prelab handouts successfully prepared students for canned labs (without need of extensive lecture)
Students did not fail early enough! (They did not buy into the idea of prototyping)
Prelabs for challenge labs: plans and troubleshooting brainstorms, with prioritization
Students had a hard time “stepping back” and analyzing WHY something was an issue/problem(what is the underlying constraint?)
Being visual—an excellent means of communication & building a frameworkStudents report success in optics research labs (Arizona Optical Sciences, Colorado, Brandeis, ...)
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
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