Tuesday, November 16, 2010

Fall 2010/Spring 2011

Garrett Potter is working on the vacuum system and Zeeman slower for the calcium MOT as part of his senior capstone project. We are currently thinking about a slower with permanent magnets, similar to this paper by Ovchinnikov. Not having to wrap coils and run high currents through them with the potential danger of shorting them is very tempting.

Kristen Norton is working on the laser system and build-up cavity for the calcium MOT, also as part of her senior capstone project. She has already built the mount for the tapered amplifier that we will use to increase the power of a diode laser before frequency doubling it.

Sam Nhim is finishing up a paper from our summer research.

Matthew Bateman is transferring the working PI design from a test board to a printed circuit board using PCBExpress.

Summer 2010

This summer, Samantha Nhim and Kristen Norton were working with me on rubidium absorption spectroscopy using circularly polarized light. Our results have been presented at the NW APS meeting and at the M.J. Murdock conference.

Fall 2009/Spring 2010

  Two of our seniors, Elyse McEntee and CJ Koll, were working on my project as part of their senior capstone project (this year for the last time only one semester long).

  Elyse's focus were the PI controllers for the laser system. She built several circuits which could be connected in a modular way to allow a high degree of flexibility and adjust the whole circuit easily for many different purposes.
Elyse also wrote two LabView programs that read in signals from the circuits and from our vacuum gauge.

  CJ began calculations on a frequency doubling cavity which will be used to trap the alkaline-earth atom.

  My lab also got an upgrade: A brand new (and heavy!) optical table.

Summer 2009

My first participation in Willamette's Science Collaborative Research Project, SCRP. Garrett Potter and Marc Whitehead were working with me for 9 weeks between June and August and finished the assembly of the laser system. 

And here are our first ultracold Rubidium atoms (created on 07/01/09):

 Check out our SCRP story here.

Fall 2008/Spring 2009

The first optical elements are being assembled.
The lab, still pretty empty.

My first year here at Willamette. We used the Fall 2008/Spring 2009 year to prepare the lab for work on ultracold atoms, purchased the necessary equipment to get us started and began initial assembly of the apparatus. I am very happy that several students were interested in helping me with this task. They assembled a laser diode from scratch and worked on finding the right wavelength by sending the laser beam through a glass cell containing room temperature rubidium atoms and looking for an absorption signal.
Garrett Potter
Matt Titus
Garrett Potter and Matt Titus began work on PID controllers, electronic devices which allow us to “lock” the laser frequency. Their initial work was continued during the Spring 2009 semester when students mass-produced photodiodes and differential amplifiers - two components that are part of the complete controller circuit - as part of the ATEP class. Garrett and Matt were joined by Kyle Kotaich, Marc Whitehead and Thomas Eliot for part of the semester, who adjusted the laser frequency and took first absorption spectroscopy measurements. 

Marc Whitehead
Thomas Eliott

Kyle Kotaich
More baking.
Baking the vacuum chamber.
We also assembled and baked the vacuum chamber. This was probably the most nerve-wracking part as I was not sure that the chamber had survived the transport from Rochester without any damage. Turns out, it has. After a week of baking we were in the low 10-9 Torr range already, and the pressure has dropped to the middle 10-10 Torr since.
The clean chamber.

The clean chamber.