Low cost ECDL and control toolkit for Rb hyperfine interaction

MARCELO A. LUDA; JORGE CODNIA; LAURA AZCARATE

Congreso; Quantum Optics VII; 2014

High coherence tunnable laser are a fundamental tool for several techniques used often on atomic physics, laser spectroscopy and quantum optics. Most of these techniques include mode-hop-free frequency tunning,locking laser to hyperfine transition frequency and laser cooling on MOTs devices. In this work we present an ECDL built from low cost components and a diode laser extracted from a CD-RW, suitable for Rb hyperfineinteraction. Frequency selectivity is obtained with a diffraction grating feedback, which is mounted on a piezoelectric transducer (PZT) for position/angle control, and controlling diode temperature and current supply.We developed specific electronic circuits for current, temperature and PZT drivers, which are controlled from an Ardunio microcontroller connected to a PC. The simultaneous tunning of these three variables enabledthe possibility to make large mode-hop-free frequency tunning (~40 GHz) near the Rb 5 2 P 3/2 ← 5 2 S 1/2 transition ( 780±2 nm). This toolkit was tested on a saturated absorption spectroscopy setup used to measure thehyperfine structure of 85,87 Rb. We used a Rb vapor cell with natural isotope abundance (70% 85 Rb - 30% 87 Rb) for analysis. The spectra acquired let us estimate the isotope composition and identify all the hyperfinetransitions of the D 2 -line and the cross-over peaks. Also, we tested an algorithm for digital locking to one of the spectra peaks and could reach frequency stabilization around 40 MHz line-width.