A CO2 TO VISIBLE OPTICAL FREQUENCY-SYNTHESIS CHAIN - ACCURATE MEASUREMENT OF THE 473 THZ HENE/I2 LASER

We have built an optical frequency synthesis chain starting from our laboratory-measured reference at 29 THz (CO2/OsO4 laser) and we have measured the frequency of a HeNe laser locked on a hyperfine transition of iodine at 473 THz. The result of the measurement of the laser locked on the ''f'' component of the (127)R11-5 transition is nu=473 612 353 586.9+/-5 kHz. The given uncertainty (DELTAnu/nu=1X10(-11)) is 10 times better than the previous published measurement. It is only limited by the reproducibility of that standard laser. Our chain is potentially capable of measuring optical frequencies from the visible down to the near infrared range with an accuracy level of 10(-12), which is presently limited by our reference accuracy.