Sophie Narashiba is from Honolulu. She graduated from Iolani School in 2023 and currently attends Reed College majoring in Physics. She plans to pursue physics and mechanical engineering through the 3-2 engineering program. During her free time she enjoys playing video games, reading, and embroidery.
Home Island: O‘ahu
High School: Iolani School
Institution when accepted: Reed College
Project Site: University of California Observatories, Santa Cruz, California
Mentor: Renate Kupke
Project title: Designing and Testing the Diffraction Grating Mount for the FOBOS Instrument
Project Abstract:
The Fiber-Optic Broadband Optical Spectrograph (FOBOS) project seeks to deploy a high-multiplex deep spectrographic facility on the Keck II telescope. Diffraction gratings split the incoming light wave into its spectral frequencies, allowing spectrographs to extract information from the collected light. My project focuses on testing the efficiency of the fused-silica etched (FSE) ultraviolet (UV) grating for the four spectrographs on FOBOS. FSE gratings are lithographically etched compared to regular ruled gratings that are mechanically etched. This results in less scatter, especially in the UV range where the light waves are small enough to scatter off the imperfections in the mechanically ruled grating. The FSE grating is 180 mm x 180 mm x 9 mm, thus requiring precise measurements at multiple locations to ensure consistency. Due to this, the existing testing aperture must be rebuilt to accommodate the FSE grating’s larger size, including a new mount for the grating itself. Both the prototype and final mount were designed on computer-aided design (CAD) software and 3D printed. The efficiency will be characterized using both a camera and a photometer to be compared against theoretical models. Both the final mount design and the results of the tests conducted on the FSE grating will be documented and reported.