Research Projects

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1. Optical Alignment for High-Precision Systems

I investigate a new alignment sensing scheme for optical cavities named Radio Frequency Jitter Alignment Sensing Scheme (RFJAS). This scheme is proposed to work along with the currently used WaveFront Sensing Scheme. RFJAS relies on using an electro-optic beam deflector to generate first higher order modes (HOM) sidebands. These sidebands case be used to beat with first HOM from misalignment. Demodulating this beat signal recovers full alignment of the optical cavity, when operating the correct modulation frequency. A schematic of the setup is attached. In there we see the laser source, the electro-optic beam deflector, and 2 steering mirrors that I call PZT1 and PZT2, then the optical cavity.

Translation DOF
Tilt DOF
Read full paper (PDF) See the animation

2. Automation of Optical Bench Using LabVIEW

Experimental work in general involves using multiple instruments and devices. It would take a long time to take a single measurement if I had to do that manaually. As a result, I learned LabVIEW and I automated my entire experiment. Attached is a picture of my first LabVIEW code I built. This script sets modulation/demodulation frequency and phase of the electro-optic beam deflector, then it drives tilt alignment degree of freedom, by communicating with a function generator that is connected to steering mirrors, and saves the response of the photodiode on reflection in a TXT file. Then, it drives the lateral degree of freedom, and again, it saves the response of the photodiode. Finally, it updates the modulation/demodulation frequency and phase and repeats this process for any N number of iterations I provide.

LabVIEW code

3. COMSOL

COMSOL is powerful to model optical compoentns. I used it to model the change in index of refraction inside lithium tantalate (LiTaO3) due to an applied radio frequency voltage across the crystal. This results in beam deflection. The modeled angle of deflection agreed pretty well with the measured angle. Figure 1 shows the electric field inside the crystal as simulated in COMSOL. While Figure 2 shows the electric field inside an electro-optic lens. This lens is used for mode mismatch sensing, rather than optical alignment.

EOBD
Figure 1: Electric Field inside the EOBD
EOL
Figure 2: Electric Field inside the EOL
EOL
Figure 3: Electric Field at the Center of the EOL

4. Zemax (Side Project)

I played around with Zemax to simulate Gaussian beam propagation through different lens setups. It wasn’t part of any research project, but more of a side exploration to understand beam shaping and how design choices like curvature and spacing affect focus and waist. It was super helpful in building intuition for tweaking optical systems in the lab.