The hours I spend in the physics and chemistry labs of St. Lawrence University make me a bit inured to the optical shenanigans occurring when we take Raman spectra of the materials my students synthesize. Still, the effect is pretty fantastic. The grainy pattern of the laser on surfaces around lab is fantastic, but the fluorescence ink on the post-it note in the foreground fluorescing aggressively is pretty cool, too.
That violet-blue light in the background of the shot above is the 405 nm laser we use to initiate photochemical processes. The beam is poorly detected by the camera’s sensor, but the slightest hint of it is visible in the upper third of the image below.
In St. Lawrence’s Raman spectroscopy and microscopy lab, the most potent laser illumination source comes from a neodymium-doped yttrium aluminum garnet. This is a pretty ubiquitous laser source, but I happen to like it because it also demonstrates the value of nonlinear optics: though this laser is emitting light at 1064 nanometers (in the infrared), a suitable doubling crystal can combine two of those 1064 photons together to make a shiny new 532 nm photon.
The laboratories of physical scientists across the planet have pulsed laser systems like this one, and many look quite similar: a collection of squat boxes covering optics, electronics, and beampaths. Above or below the surface of the table are additional boxes of electronics driving the lasers and detectors. This particular system is special to me for two reasons: (1) most modern laser tables don’t have rad wood grain paneling, and (2) this was the instrument I used during my sabbatical at Berkeley Lab last spring. Lots of good data emerged from its photomultiplier tube.
I am a spectroscopist, and this is my laser. It’s enormous, it’s fiendishly complicated, and it takes an enormous amount of time to keep it cooperative. Nonetheless, I can learn about the basic motions of molecules with it.
The farther along I get, the more I realize that the system basically amounts to Legos for big kids.