Jennifer DeLeon Maui Community College Mentor: Nathan Sabin Advisor: Dan O’Connell

1. Generating Lenses Jennifer DeLeon Maui Community College Mentor: Nathan Sabin Advisor: Dan O’Connell

2. The goal of the project: • Edging • Cutting the radius • Grinding • Polishing • Testing • Coating Make a set of 2 zoom lenses from SF-11. The lenses will be used together to adjust the divergence of a laser beam. Generating Lenses

3. Preparation: Blocking Up generator body substrate hot plate

4. Step 1: Edging

5. Step 1: Reference Cut • Put in generator, lens is centered, left to cool • Cutting head adjusted to 35 degrees • Reference cut made • Subtract final diameter from measured and divide by 2

6. Prep for step 2: sag tool diameter [ ] (radius curvature) radius curvature center thickness lens diameter ANGLE = sin-1 2 (½ lens diameter)2 SAG = (radius curvature) 2 ( ) current thickness finished thickness - + tolerance + .5mm MATERIAL TO REMOVE = 2

7. Step 2: Cutting the Radius cutting head coolant line spindle

8. Step 2: Spherometer • Measure lens surface w/ spherometer • If radius is too steep or flat, make adjustments • Take off remaining material for that side • Reheat assembly, flip lens and repeat process

9. Step 3: Grinding • Grinding tools made in house • Grooves allow compound and material to flow • 30 micron = .150 mm, 12 micron = .075 mm, 5 micron = .025 mm • Repeatedly tested with dial-meter and spherometer

10. Step 3: Wedge Correction • Place the lens on a 3 point plane • Use V-block to reference diameter and a dial-meter to test high spot • Hand grind to within decentration tolerance

11. Step 4: Polishing • Polishers made with warm optical pitch • After cooling, patterns are cut to allow compound and pitch to flow • Polishing arm moves in several directions • More of an art than an exact science • Adjustments are made throughout process and lens is tested after each run

12. Step 5: Testing • Interferometry = The use of an instrument that uses the interference of light waves to measure the accuracy of an optical surface • 2 fringes = 1 wave deviation from desired (or test plate) radius • The radius of curvature can be measured more accurately with a test plate than irregularity. • Irregularity = Any distortion in the symmetry of the rings • Also inspected with a loupe (magnifier) for any cosmetic blemishes

13. Results • A set of two zoom lenses • Meeting the cosmetic and fringe specifications and were sent out for coating • When put together form a meniscus lens that diverges a laser beam • When moved apart start to converge the laser beam • In this way, they are used to adjust the divergence of a laser beam

14. Special Thanks Center for Adaptive Optics Institute for Astronomy Lani LeBron Lisa Hunter Maui Community College Mark Hoffman Akamai Instructors Dave Harrington Ryan Montgomery Isar Mostafanezhad Mark Pitts Scott Seagroves Sarah Sonnet The Akamai Interns Lowen Okamoto Darcy Bibb Jesse Brinkman Kenneth Estores Brylian Foronda David Kim Trent Kyono Jennifer Liem Shanoa Miller Nathaniel Salazar Tyson Seto-Mook Roxanne Yee Tyler Yoshiyama Jiaquan Zheng Suzanne Burns Hnu Photonics Team Including: Nathan Sabin Chris Taylor Dan O’Connell Sukumar Murali The Akamai Internship Program is funded by the Center for Adaptive Optics through its National Science Foundation Science and Technology Grant (#AST-987683) and by grants to the Akamai Workforce Initiative from the National Science Foundation and Air Force Office of Scientific Research (both administered by NSF,#AST-0710699) and from the University of Hawaii.