1. Graham Lochead 07/09/09 Pulsed laser spectroscopy in strontium

2. Graham Lochead 07/09/09 Outline Strontium project update Ladder EIT Electron shelving spectroscopy

3. Graham Lochead 07/09/09 Project update Pyramid MOT Cavity 412 nm laser 420 nm laser

4. Graham Lochead 07/09/09 Optical setup Cell 461 nm light from fibre FPD Aperture DispenserBaffle Lens ~5 mm beam diameter 10 Hz repetition 10 ns pulse duration ~20 mJ per pulse ~5 nm tuning range ~2 GHz linewidth Dye laser parameters Pump laser Dye laser

5. Graham Lochead 07/09/09 Ladder EIT (I) Probe: 5s 2 1 S 0 → 5s5p 1 P 1 Couple: 5s5p 1 P 1 → 5snd 1 D 2 5s 2 1 S 0 5s5p 1 P 1 5snd 1 D 2 lg> le> lr> 461 nm 413 nm 1 P 1 lifetime ~ 5 ns, Rydberg lifetime ~ 10 μs ωeωe ωrωr ωpωp ωcωc ΔpΔp ΔcΔc J.P. Marangos, J. Mod. Opt 45, p. 471-503 (1998)

6. Graham Lochead 07/09/09 Ladder EIT (II) Diagonalization of the Hamiltonian leads to new eigenstates: For Ω c >> Ω p and Δ p = 0 Probe couples to excited state of both |+> and |-> which have equal but opposite transition probabilities, thus on-resonance probe not absorbed Coherent process – decoherence effects increase absorption

7. Graham Lochead 07/09/09 Simulations Solve three level optical Bloch equations Rydberg transition Rabi frequency from oscillator strength S.-U. Haq et al., EPJD 44, p. 439 (2007)

8. Graham Lochead 07/09/09 Catastrophe! Hole drilled in viewport Vacuum lost Hole Cell cleaned out Reassembled and re- evacuated Absorption seen again

9. Graham Lochead 07/09/09 Electron shelving Off-resonant two photon excitation to Rydberg state 5s 2 1 S 0 5s5p 1 P 1 5snd 1 D 2 ΩpΩp ΩcΩc 461 nm 435 nm P. Thoumany et al., Optics Letters 34, p. 1621-1623 (2009) Probe: 5s 2 1 S 0 → 5s5p 1 P 1 Couple: 5s 2 1 S 0 → 5snd 1 D 2 Unlikely to see EIT due to large decoherence Rydberg state has a long lifetime relative to 1 P 1

10. Graham Lochead 07/09/09 Outlook Change dye to attempt electron shelving Finish building pyramid MOT