Long ULE Cavities with Relative Fractional Frequency Drift Rate below 5 × 10–16/s for Laser Frequency Stabilization

48 -cm-long room-temperature cavities in vertical and horizontal orientations for Sr optical clock

“…The frequency drift of the ULE glass cavities is associated with the compression of the cavity spacer, usually explained by glass degassing. The relative frequency drift of the two systems was studied in 36 and turned out to be about 200 mHz/s. We expect that the drift will be reduced during aging of the systems and will reach tens of mHz/s in a few years.…”

“…and optical imperfections (optical etalons, power fluctuations, etc.). To characterize the noise of the optoelectronic feedback loops we performed the comparison between two individual lasers locked to the single (vertical) cavity, similar to the method described in 36 . We locked two lasers to two frequency-separated TEM00 modes of the vertical cavity spaced by two FSRs.…”

Dual-mode stabilization for laser to radio-frequency locking by using a single-sideband modulation and a Fabry–Pérot cavity

“…Another method is to use an ultrastable optical cavity to purify the laser frequency [19][20][21][22][23] . In addition to the cavity finesse, the consistency of the cavity length plays a dominant role in laser performance.…”

Frequency stabilization of multiple lasers to a reference atomic transition of Rb

“…Laser cooled ytterbium ion ( 171 Yb + ) offers two ultra-narrow clock transitions in the optical domain, i.e., a quadrupole transition at 435 nm and an octapole transition at 467 nm with natural line width of 3 Hz and 3 nHz respectively 18 , 19 . Stabilizing of clock laser’s frequency, for probing such ultra-narrow transitions, requires tremendous effort for generating ultra-stable and ultra-narrow linewidth frequency using ultra low expansion (ULE) cavity 1 , 20 – 22 and fast servo controller. Atomic transitions used for the production of ytterbium ions through photoionization, laser cooling of ions and repumping of the metastable states of the ions, have typical natural linewidth of tens of MHz and therefore the frequencies of those lasers need to be stabilized within same range, i.e., few tens of MHz for the above purposes 5 .…”

“…For example, precision spectroscopy or high accuracy metrology-related experiments demand relative frequency instabilities 18 better than 10 −15 whereas other experiments such as atomic spectroscopy or atom cooling can be performed with laser frequencies having short-term instabilities ≤ 10 −10 .Laser cooled ytterbium ion ( 171 Yb + ) offers two ultra-narrow clock transitions in the optical domain, i.e., a quadrupole transition at 435 nm and an octapole transition at 467 nm with natural line width of 3 Hz and 3 nHz respectively 18,19 . Stabilizing of clock laser's frequency, for probing such ultra-narrow transitions, requires tremendous effort for generating ultra-stable and ultra-narrow linewidth frequency using ultra low expansion (ULE) cavity 1,[20][21][22] and fast servo controller. Atomic transitions used for the production of ytterbium ions through photoionization, laser cooling of ions and repumping of the metastable states of the ions, have typical natural linewidth of tens of MHz and therefore the frequencies of those lasers need to be stabilized within same range, i.e., few tens of MHz for the above purposes 5 .The present article reports about simultaneous and long terms frequency stabilization of four different lasers, used for production and laser cooling of ytterbium ions, through a wavelength meter.…”