As a graduate student at Caltech and researcher at NASA's Jet Propulsion Laboratory, I work on many interesting things...
Check out some of my most current research below!
GQuEST
Description
GQuEST (Gravity from the Quantum Entanglement of Space-Time) is a highly sensitive interferometer capable of searching for signals at roughly 15 MHz on the order of 3 * 10 -22 m/sqrt hz. Typical interferometers will be shot noise limited at these scales thus to achieve these detections we will “surpass” the standard quantum limit by using integration statistics from photon counting. GQuEST will then cross-correlate two interferometers to create a coherent signal to be read out using SNSPDs.
My Role
- Design and implement hardware electronics and calibrated photon measuring instrumentation including SNSPDs and avalanche photodiodes
- Operate and maintain cryogenic systems for SNSPDs and fiber optics to achieve low thermal radiative outputs from the interferometer
- Develop and align quantum optic layouts and systems including power distribution and LASER cavity amplifiers.
- Develop code for network-attached devices for autonomous laboratory calibrations and experiements
Outcome
The outcome of GQuEST is forthcoming, but we are working to achieve novel discoveries of quantum gravity as well as demonstrating the first photon-counting interferometer experiments.
Publications
S. Vermeulen, T. Cullen, D. Grass, I. MacMillan, A. Ramirez, J. Wack, B. Korzh, V. Lee, K. Zurek, C. Stoughton, L. McCuller, "Photon Counting Interferometry to Detect Geontropic Space-Time Fluctuations with GQuEST," April 2024, arXiv:2404.07524.
SNSPD
Description
SNSPDs (superconducting nanowire single-photon detectors) are cutting-edge photon detectors that utilize superconducting materials to detect individual photons with extremely high efficiency. This technology is crucial in quantum communication, quantum computing, and experimental physics, where detecting single photons is key.
My Role
- Performed calibration and optimization of the SNSPDs for improved quantum efficiency and low dark counts
- Developed software tools for real-time signal processing and data analysis from photon detection events
- Conducted experimental tests on cryogenic systems to ensure stable detector operation in ultra-low temperature environments
Outcome
The project contributed to significant advancements in photon detection technologies, improving the feasibility of large-scale quantum networks and experiments.
Submersible Digital Holographic Microscope
Description
This project involves designing and deploying a submersible instrument equipped with a digital holographic microscope (DHM) and sensors to collect holographic images of microbes and environmental data in the ocean. The instrument is capable of operating at significant depths and is intended to function autonomously. This technology plays a crucial role in marine research, helping scientists understand oceanic processes and their impact on climate.
My Role
- Designed the submersible, sensor network and integrated the system for real-time data collection
- Optimized and constructed the code for autonomy and portability for field use
- Enhanced the instrument's performance to function effectively under high-pressure underwater environments
- Ensured accurate calibration of all sensors and conducted field tests for reliability in real-world oceanic conditions
Outcome
Design of a new 1000-meter capable instrument with onboard machine learning to classify microbes in-situ and autonomously.
Publications
A. Ramirez, T. Burch and J. K. Wallace, "Design of a Low-cost, Submersible, Digital Holographic Microscope for in Situ Microbial Imaging," 2022 IEEE Aerospace Conference (AERO), 2022, pp. 1-7, doi: 10.1109/AERO53065.2022.9843489.
J. K. Wallace, R. Bartos, C. Walch, and A. Ramirez, "Going to Extremes: Architecting Holographic Microscopes for Extreme Environments," 2022 IEEE Aerospace Conference (AERO), 2022, pp. 1-6, doi: 10.1109/AERO53065.2022.9843199.
Alexander Ramirez, Ben Schierman, Lihao Zheng, Brandon Dalporto, Lena Belvin, Tyler Burch, Andrew Mullen, and James Wallace. "A low-cost submersible digital holographic microscope for in situ microbial imaging," in OSA Optical Sensors and Sensing Congress 2021 (AIS, FTS, HISE, SENSORS, ES), S. Buckley et. all, OSA Technical Digest (Optical Society of America, 2021), paper JTu5A.18.
LIGO
Description
LIGO (The Laser Interferometer Gravitational-Wave Observatory) is a large-scale physics experiment and observatory designed to detect cosmic gravitational waves and test Einstein's theory of general relativity. The instrument relies on highly sensitive interferometers to measure minuscule changes in distance caused by passing gravitational waves. At Caltech, I have worked on the 40-meter prototype to improve control systems and optimize sensitivity.
My Role
- Worked on optimizing the interferometric alignment and tuning the laser systems for improved sensitivity
- Created formalisms to calculate beam spot movements within a mode cleaner cavity seen from quadrature photodiodes
- Applied broadband noise injection of asynchronous signals into a mirror suspension system to calibrate the control system and stabilize feedback loops
Outcome
Helped improve processes for optimizing control loops and identifying beam spot misalignments.