Diode-Pumped Nd:FAP Laser at 1.126 microm: A Possible Local Oscillator for a Hg+ Optical Frequency Standard

Area of Science:

• Atomic Physics
• Laser Science
• Metrology

Background:

• Optical frequency standards are crucial for precise timekeeping and fundamental physics.
• Trapped ions, such as mercury (Hg+), offer highly stable atomic transitions for frequency standards.
• Developing stable laser sources at specific wavelengths is essential for interrogating these transitions.

Purpose of the Study:

• To report the development and efficient operation of a continuous-wave, single-frequency, diode-pumped Neodymium-doped Fluorapatite (Nd:FAP) laser at 1.126 µm.
• To explore the potential application of this laser, after frequency quadrupling, as a local oscillator for an optical frequency standard.
• To investigate its use in conjunction with the (2)S(1/2)-(2)D(5/2) electric quadrupole transition of trapped and laser-cooled (199)Hg(+) ions.

Main Methods:

• Utilized a diode-pumped Neodymium-doped Fluorapatite (Nd:FAP) laser.
• Operated the laser in a continuous-wave (CW) and single-frequency mode.
• Considered frequency quadrupling of the laser output for application in optical frequency standards.

Main Results:

• Achieved efficient operation of the continuous-wave, single-frequency, diode-pumped Nd:FAP laser at 1.126 µm.
• Demonstrated the potential for frequency quadrupling this laser.
• Proposed its use as a local oscillator for a (199)Hg(+) ion optical frequency standard.

Conclusions:

• The developed Nd:FAP laser is a viable source for optical frequency standard applications.
• Frequency quadrupling enables its use with the mercury ion clock transition.
• Harmonic relationship simplifies phase-coherent frequency measurements to the cesium primary standard.