1. Sensitivity of Slope to B GHz-1/G B Field (G) 290 326 Sensitivity of Lock Pt to B σ+ σ– 302 338 MHz/G 314 358 M = -1 M = 0 M = +1 Indicates optimal pt For B≠0 λ/4 plate Polarizer B Field (G) PBS Vapor Cell LASER Model Data Permanent Magnets Detectors 100 220 140 260 180 280 Indicates optimal pt Theoretical Optimization of a DAVLL System for a Rubidium Vapor Joel A. Greenberg, Andrew M. C. Dawes, Daniel J. Gauthier Quantum Electronics Lab, Physics Department, Duke University Introduction Experimental Data Here we show sensitivity to B field changes MOTIVATION: Experimental Setup • Model and optimize a simple, robust, laser frequency lock system METHOD: Dichroic Atomic Vapor Laser Lock (DAVLL)1 Temp (K) • Zeeman effect shifts energy levels • Resonant frequencies shift down/up for σ+/σ- Model vs. Experiment Absorption Scan Difference Signal • Subtracting the shifted absorption signals produces a dispersion-like curve suitable as an error signal Diff Signal Transmission Absorption Profile Difference Signal Conclusions σ+ - σ- σ- σ+ Frequency (MHz) Frequency (MHz) Optimal conditions for a D2 lock in a 7.5cm Rb87 cell: B~260 G, T~335 K Optimization • Slope = 2 GHz-1 • Capture range = 0.5 GHz GOALS: • Choose the combination of B and T which : • Provides a large but insensitive slope • Provides a difference signal with an insensitive lock point • Produces a signal which is suitably linear • Produces a broad capture range Sensitivity of Slope to T • Within ± 5 K and ±2.5 G of the optimum conditions, the signal fluctuates as: • slope sensitivity: <0.5 (1/GHz)/K <0.1 (1/GHz)/G • lock point sensitivity: 0 ± 10 KHz/K 50 ± 50 KHz/G • capture range variation: 0 ± 20 MHz/K 4 ± 1 MHz/G GHz-1/K Here we show sensitivity to temperature changes Temp (K) The Model B Field(G) Sensitivity of Lock Pt to T MHz/K Citations 1) Corwin, Lu, Hand, Epstein, Wieman: Appl. Opt. 37, 3295 (1998) 2) Beverini, Marsili, Ruffini, Sorrentino: Appl. Phys. B 73, 133-138 (2001) Hamiltonian Output intensity 2 Temp (K) Funding US Army Research Office (grant # W911NF-05-1-0228)