A pyramid MOT with integrated optical cavities as a cold atom platform for an optical lattice clock.

We realize a two-stage, hexagonal pyramid magneto-optical trap (MOT) with strontium, and demonstrate loading of cold atoms into cavity-enhanced 1D and 2D optical lattice traps, all within a single compact assembly of in-vacuum optics. We show that the device is suitable for high-performance quantum technologies, focusing especially on its intended application as a strontium optical lattice clock. We prepare 2 × 10 spin-polarized atoms of Sr in the optical lattice within 500 ms; we observe a vacuum-limited lifetime of atoms in the lattice of 27 s; and we measure a background DC electric field of 12 V m from stray charges, corresponding to a fractional frequency shift of (-1.

Suppression of amplitude-to-phase noise conversion in balanced optical-microwave phase detectors.

We demonstrate an amplitude-to-phase (AM-PM) conversion coefficient for a balanced optical-microwave phase detector (BOM-PD) of 0.001 rad, corresponding to AM-PM induced phase noise 60 dB below the single-sideband relative intensity noise of the laser. This enables us to generate 8 GHz microwave signals from a commercial Er-fibre comb with a single-sideband residual phase noise of -131 dBc Hz(-1) at 1 Hz offset frequency and -148 dBc Hz(-1) at 1 kHz offset frequency.

Spectroscopic applications of femtosecond optical frequency combs.

Over the past twelve years, notable advances have occurred in a diverse range of scientific areas following the development of femtosecond optical frequency combs. Compared to a conventional laser source, the distinguishing feature of a femtosecond comb is that it provides a broadband source with well-defined phase coherence across the optical spectrum. This makes it a unique tool for spectroscopic applications, simultaneously providing high spectral resolution and broad spectral coverage.

Dissemination of an optical frequency comb over fiber with 3 × 10(-18) fractional accuracy.

We demonstrate that the structure of an optical frequency comb transferred over several km of fiber can be preserved at a level compatible with the best optical frequency references currently available. Using an optical phase detection technique we measure the noise introduced by the fiber link and suppress it by stabilizing the optical path length. The measured fractional frequency stability of the transferred optical modes is 2 × 10(-18) at a few thousand seconds and the mode spacing stability after optical-microwave conversion is better than 4 × 10(-17) over the same time scale.

High-resolution microwave frequency transfer over an 86-km-long optical fiber network using a mode-locked laser.

We demonstrate the transfer of an ultrastable microwave frequency by transmitting a 30-nm-wide optical frequency comb from a mode-locked laser over 86 km of installed optical fiber. The pulse train is returned to the transmitter via the same fiber for compensation of environmentally induced optical path length changes. The fractional transfer stability measured at the remote end reaches 4×10(-17) after 1600 s, corresponding to a timing jitter of 64 fs.

Common-path self-referencing interferometer for carrier-envelope offset frequency stabilization with enhanced noise immunity.

A nonlinear interferometer design for stabilizing the carrier-envelope offset frequency of a Ti:sapphire frequency comb with superior immunity to air currents and acoustic noise is presented. The scheme uses a pair of Wollaston prisms for group-delay dispersion compensation, providing an all-common-path optical configuration. Out-of-loop phase noise measurements for an unshielded interferometer setup showed up to 15 dB improvement compared to a Michelson interferometer based system.

High-stability microwave frequency transfer by propagation of an optical frequency comb over 50 km of optical fiber.

A high-stability microwave frequency reference is transferred over 50 km of spooled optical fiber by propagation of a 90-nm-wide optical frequency comb centered at 1.56 microm. Environmentally induced fiber phase noise is actively suppressed by returning the optical frequency comb via a separate fiber.

Frequency measurement of the 2S(1/2)-2D(3/2) electric quadrupole transition in a single 171Yb+ ion.

We report on precision laser spectroscopy of the 2S(1/2)(F = 0)-2D(3/2) (F = 2, m(F) = 0) clock transition in a single ion of 171Yb+. The absolute value of the transition frequency, determined using an optical frequency comb referenced to a hydrogen maser, is 688358979309310 +/- 9 Hz. This corresponds to a fractional frequency uncertainty of 1.

Absolute frequency measurement of a 1.5-microm acetylene standard by use of a combined frequency chain and femtosecond comb.

We have developed and characterized a pair of Doppler-free acetylene-stabilized diode laser frequency standards as optical communications references. The Allan deviation sigma/f of an individual system reaches a minimum of 4 x 10(-14) at a sampling time of 5000 s, and the long-term lock-point repeatability is found to be 0.4 kHz (one standard uncertainty), corresponding to a fractional uncertainty of 2 x 10(-12).