II. Vapor cell spectroscopy and blue/UV diode lasers
polarimeter optics and thallium vapor cell furnace
We also produce samples of our heavy metal, Group IIIA atoms using heated quartz vapor cells. Several experiments have been completed in thallium using diode laser systems. First, an infrared diode laser system at 1283 nm was used to measure the ratio of E2 to M1 quantum mechanical transition amplitudes in the 6P1/2 – 6P3/2 ‘forbidden’ transition using transmission as well as Faraday rotation spectroscopy. We also used the same frequency-doubled diode laser system at 378 nm to measure hyperfine structure and isotope shift within the 6P1/2 – 7S1/2 E1 transition in thallium.
In the foreground of this photo, one can see a typical quartz vapor cell. Long empty quartz tubes extend from the cell face well outside of the oven body to eliminate the noise produced by convection currents of hot air near the oven entrance and exit apertures.
GaN diode lasers
Recently, with the advent of GaN blue/UV diode lasers, we have pursued spectroscopy of indium, where a diode laser system at 410 nm drives the ground-state 5P1/2-6S1/2 transition. We also have a GaN system operating at 378 nm, producing light for our thallium experiments WITHOUT the need for frequency-doubling! Below you can see the blue/violet beam path, as well as the red glow from the small indium furnace, heated to about 800 degrees C for sufficient vapor pressure.
Toptica DL100 system @410 nm.
We also have in our laboratory a GaN-based external cavity laser system (Sacher Lasertechnik) operating at 378 nm for thallium spectroscopy.