High-resolution spectroscopy with a femtosecond laser frequency comb.

Area of Science:

• Atomic Physics
• Quantum Optics
• Laser Spectroscopy

Background:

• Mode-locked femtosecond lasers offer unique pulse characteristics for high-resolution measurements.
• Cesium (133Cs) atomic transitions are fundamental for atomic clock applications.
• Single-photon spectroscopy requires precise control over laser parameters.

Purpose of the Study:

• To investigate the application of mode-locked femtosecond laser output for precision single-photon spectroscopy of 133Cs.
• To measure the optical frequencies of cesium D1 and D2 transitions using a femtosecond laser.
• To demonstrate the feasibility of a simple cesium optical clock based on femtosecond laser technology.

Main Methods:

• Utilizing the output of a mode-locked femtosecond laser for single-photon spectroscopy.
• Adjusting the laser's repetition rate to probe specific cesium transitions (D1 and D2).
• Employing atomic fluorescence detection and feedback control to stabilize the laser repetition rate.

Main Results:

• Accurate detection of 133Cs D1 and D2 transitions.
• Optical frequencies measured with accuracy comparable to continuous-wave (cw) lasers.
• Successful implementation of femtosecond laser repetition rate control via atomic fluorescence.

Conclusions:

• Femtosecond lasers can achieve precision comparable to cw lasers in atomic spectroscopy.
• The controlled repetition rate of a femtosecond laser enables the realization of a simple cesium optical clock.
• This work highlights a novel approach for developing compact and accurate atomic clocks.