Optical frequency metrology

@article{Udem2002OpticalFM,
  title={Optical frequency metrology},
  author={Thomas Udem and Ronald Holzwarth and Theodor W. H{\"a}nsch},
  journal={Nature},
  year={2002},
  volume={416},
  pages={233-237}
}
Extremely narrow optical resonances in cold atoms or single trapped ions can be measured with high resolution. A laser locked to such a narrow optical resonance could serve as a highly stable oscillator for an all-optical atomic clock. However, until recently there was no reliable clockwork mechanism that could count optical frequencies of hundreds of terahertz. Techniques using femtosecond-laser frequency combs, developed within the past few years, have solved this problem. The ability to… 

Femtosecond optical frequency combs

A laser frequency comb allows the conversion of the very rapid oscillations of visible light of some 100’s of THz down to frequencies that can be handled with conventional electronics. This

Precision spectroscopy of hydrogen and femtosecond laser frequency combs

  • T. HänschJ. Alnis M. Zimmermann
  • Physics
    Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
  • 2005
TLDR
Precision spectroscopy of the simple hydrogen atom has inspired dramatic advances in optical frequency metrology and is setting new limits for possible slow variations of the fine structure constant α and the magnetic moment of the caesium nucleus μCs in units of the Bohr magneton μB.

Frequency combs and applications

  • T. Udem
  • Physics
    2013 Conference on Lasers and Electro-Optics Pacific Rim (CLEOPR)
  • 2013
A laser frequency comb allows the conversion of the very rapid oscillations of visible light of some 100's of THz down to frequencies that can be handled with conventional electronics. This

Passion for Precision (Nobel Lecture)

Optical frequency combs from mode-locked femtosecond lasers have revolutionized the art of counting the frequency of light. They can link optical and microwave frequencies in a single step, and they

Einstein Lecture – Passion for precision

Optical frequency combs from mode‐locked femtosecond lasers have link optical and microwave frequencies in a single step, and they provide the long missing clockwork for optical atomic clocks. By

Einstein Lecture – Passion for precision *

Optical frequency combs from mode‐locked femtosecond lasers have link optical and microwave frequencies in a single step, and they provide the long missing clockwork for optical atomic clocks. By

Kilohertz-resolution spectroscopy of cold atoms with an optical frequency comb.

TLDR
The potential for high-resolution absolute-frequency spectroscopy over the entire spectrum of the frequency comb output using a single high-finesse optical reference cavity is demonstrated.

Direct frequency comb optical frequency standard based on two-photon transitions of thermal atoms

TLDR
A novel scheme of optical frequency standard based on comb-directly-excited atomic two-photon transitions is proposed, and experimentally demonstrated, which achieves a simplified structure, high robustness as well as decent frequency stability, which promise widespread applications in various scenarios.

Femtosecond Lasers for Optical Clocks and Low Noise Frequency Synthesis

In the late 1990’s mode-locked femtosecond lasers were introduced as an important new tool for the synthesis and measurement of optical frequencies. The simplicity, robustness and improved precision

Deep-Ultraviolet Quantum Interference Metrology with Ultrashort Laser Pulses

TLDR
High-accuracy quantum interference metrology on atomic transitions is demonstrated with the use of an amplified train of phase-controlled pulses from a femtosecond frequency comb laser, paving the way for extension of frequency comb metrology in atoms and ions to the extreme ultraviolet and soft x-ray spectral regions.
...

References

SHOWING 1-10 OF 59 REFERENCES

An Optical Clock Based on a Single Trapped 199Hg+ Ion

TLDR
An all-optical atomic clock referenced to the 1.064-petahertz transition of a single trapped199Hg+ ion is demonstrated and an upper limit for the fractional frequency instability of 7 × 10−15 is measured in 1 second of averaging—a value substantially better than that of the world's best microwave atomic clocks.

Optical frequency synthesizer for precision spectroscopy

We have used the frequency comb generated by a femtosecond mode-locked laser and broadened to more than an optical octave in a photonic crystal fiber to realize a frequency chain that links a 10 MHz

Phase coherent vacuum-ultraviolet to radio frequency comparison with a mode-locked laser

TLDR
A versatile new technique is demonstrated that provides a phase coherent link between optical frequencies and the radio frequency domain and determined a new value of the hydrogen 1S-2S two-photon resonance, representing now the most accurate measurement of an optical frequency.

Absolute frequency measurement of iodine lines with a femtosecond optical synthesizer

We have used a single laser femtosecond optical frequency synthesizer together with a widely tunable Nd:YAG laser to measure the absolute frequency of several absorption lines in molecular iodine

Femtosecond-laser-based optical clockwork with instability</= less than or equal to 6.3 X 10(-16) in 1 s.

TLDR
Two octave-spanning optical-frequency combs (750-MHz comb spacing) are phase locked to a common continuous-wave laser diode and the possibility of transfering the stability and accuracy of the best current optical standards to ~500,000 individual oscillators across the visible and near-infrared spectrum is demonstrated.

Accurate measurement of large optical frequency differences with a mode-locked laser.

We have used the comb of optical frequencies emitted by a mode-locked laser as a ruler to measure differences of as much as 20 THz between laser frequencies. This is to our knowledge the largest gap

Single-Ion Optical Frequency Standards and Measurement of their Absolute Optical Frequency

This work examines the current status of research on optical frequency standards based upon single trapped ions. Methods for the containment and laser cooling of such single-ion samples are briefly

High-resolution spectroscopy of a single In ¿ ion: Progress towards an optical frequency standard

ion in a miniature radiofrequency trap isinvestigated as a possible optical frequency standard. This line at a frequency of 1267 THz ~wavelength 236.5nm! is highly immune to frequency shifts due to

Direct link between microwave and optical frequencies with a 300 THz femtosecond laser comb

TLDR
A great simplification in the long-standing problem of measuring optical frequencies in terms of the cesium primary standard is demonstrated, enabling us to measure the 282 THz frequency of an iodine-stabilized Nd:YAG laser directly in Terms of the microwave frequency that controls the comb spacing.

Phase-coherent link from optical to microwave frequencies by means of the broadband continuum from a 1-GHz Ti:sapphire femtosecondoscillator.

TLDR
It is demonstrated that the short-term stability of the microwave output of the optical clock is at least as good as that of a high-performance hydrogen maser.
...