Category: Optics

Tools of the Cold-Atom Trade: Optical Pumping and Sisyphus Cooling

Sisyphus picture from http://ssifo.blogspot.com/

This topic is an addition to the original list in the introductory post for the series, because I had thought I could deal with it in one of the other entries. Really, though, it deserves its own installment because of its important role in the history of laser cooling. Laser cooling would not be as… Continue reading Tools of the Cold-Atom Trade: Optical Pumping and Sisyphus Cooling

Tools of the Cold-Atom Trade: Optical Lattices

The famous optical lattice potential picture, from the Rolston group web site (http://www.physics.umd.edu/rgroups/amo/rolstonwebsite/bec.htm )

Last time in our trip through the cold-atom toolbox, we talked about light shifts, where the interaction with a laser changes the internal energy states of an atom in a way that can produce forces on those atoms. This allows the creation of “dipole traps” where cold atoms are held in the focus of a… Continue reading Tools of the Cold-Atom Trade: Optical Lattices

Tools of the Cold-Atom Trade: Light Shifts and Optical Dipole Traps

Schematic of a crossed-beam dipole trap from the Chen group at Chicago http://ultracold.uchicago.edu/csli_expwork

The last post in this series on the core technologies of cold-atom physics dealt with optical molasses, where you use the scattering of light to exert forces on atoms to make them very, very cold. It turns out, they end up even colder than the simple theory would lead you to expect, which is very… Continue reading Tools of the Cold-Atom Trade: Light Shifts and Optical Dipole Traps

Tools of the Cold-Atom Trade: Optical Molasses

The dormouse being stuffed into a teapot, from http://www.alice-in-wonderland.net/alice2a.html

`Once upon a time there were three little sisters,’ the Dormouse began in a great hurry; `and their names were Elsie, Lacie, and Tillie; and they lived at the bottom of a well–‘ `What did they live on?’ said Alice, who always took a great interest in questions of eating and drinking. `They lived on… Continue reading Tools of the Cold-Atom Trade: Optical Molasses

Tools of the Cold-Atom Trade: Light Scattering Forces and Slow Atomic Beams

Ryan McMartin '05 next to the Zeeman slower he built in my lab.

This series of posts is intended to explain the tools and tricks used to create and manipulate samples of ultra-cold atoms; thus, it’s appropriate to start with how we get those atoms in the first place. This will be a very quick background on the basic force used to make atoms cold, and then the… Continue reading Tools of the Cold-Atom Trade: Light Scattering Forces and Slow Atomic Beams

Tools of the Cold-Atom Trade: Introduction

Me and Emmy with some of the laser cooling apparatus in my lab.

I have a small collection of recent research papers that I’d like to write up open in various browser tabs and suchlike, but many of these would benefit from having some relatively clear and compact explanations of the underlying techniques. And while I can either dig up some old posts, or Google somebody else’s, it’s… Continue reading Tools of the Cold-Atom Trade: Introduction

Reflecting, Totally; or Why the Pool Looks Shiny from Underwater

Total internal reflection of a laser off a water surface.

The other day, I made a suggestion to one of my research students of an experiment to try. When I checked back a day later, she told me it hadn’t worked, and I immediately realized that what I had told her to do was very stupid. As penance, then, I’ll explain the underlying physics, which… Continue reading Reflecting, Totally; or Why the Pool Looks Shiny from Underwater

Photons Are Here to Stay, Deal With It

I spend a lot of time promoting Rhett Allain’s Dot Physics blog, enough that some people probably wonder if I get a cut of his royalties (I don’t). I’m going to take issue with his latest, though, because he’s decided to revive his quixotic campaign against photons, or at least teaching about photons early in… Continue reading Photons Are Here to Stay, Deal With It

What Is Squeezing?

Because nothing makes a physics post like a dated pop-culture reference. From http://www.whipple.org/photos/charmin.html

In the Physics Blogging Request Thread the other day, I got a comment so good I could’ve planted it myself, from Rachel who asks: It’s a term I see used a lot but don’t really know what it means – what is a “squeezed state”? What does “squeezing” mean? (in a QM context of course…)… Continue reading What Is Squeezing?

Atom by Atom Interaction: “Direct Measurement of the van der Waals Interaction between Two Rydberg Atoms”

Figure 2 from the paper described in the text.

I’m always a little ambivalent about writing up papers that have also been written up in Physics: on the one hand, they make a free PDF of the paper available, which allows me to reproduce figures from the paper in my post, since I’m not breaking a paywall to do it. Which makes it much… Continue reading Atom by Atom Interaction: “Direct Measurement of the van der Waals Interaction between Two Rydberg Atoms”