An optical frequency standard using strontium atoms

• Published in: 2003 European Quantum Electronics Conference. EQEC 2003 (IEEE Cat No.03TH8665) p. 303
• Main Authors: Quessada, A., Courtillot, I., Kovacich, R.P., Brusch, A., Kolker, D., Rovera, G.D., Clairon, A., Santarelli, G., Lemonde, P.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 2003
• Subjects: Atom optics; Atomic beams; Atomic measurements; Frequency; Laser beams; Optical mixing; Optical pumping; Pump lasers; Ring lasers; Strontium
• ISBN: 9780780377332; 0780377338
• DOI: 10.1109/EQEC.2003.1314160

Sr atoms are cooled on the /sup 1/S/sub 0/ /spl rarr/ /sup 1/P/sub 1/ transition at 461 nm, which linewidth is 32 MHz. Atoms from a thermal beam are decelerated by a Zeeman slower before capture in a magneto-optical trap (MOT). The MOT is formed by three retro-reflected laser beams of a total power 17 mW and of a waist radius 1 cm. The loading rate is 4 /spl times/ 10/sup 10/ atoms with up to 1.3 /spl times/ 10/sup 9/ atoms in the MOT. To generate 461 nm laser light, sum-frequency mixing of a Nd:YAG laser at 1064 nm is used and laser diodes at 813 nm in a KTP crystal. The 20 mm long crystal is placed inside a ring cavity resonant for both pump lasers with finesses of 35 at 813 nm and 75 at 1064 nm. With pump powers of 170 mW at 813 nm and 900 mW at 1064 nm, the respective coupling efficiencies are 70% and 35%. A blue light of 115 mW is obtained.