Resonantly enhanced second-harmonic generation in zinc vapor

Area of Science:

• Atomic Physics
• Nonlinear Optics
• Quantum Electronics

Background:

• Coherent harmonic generation is crucial for developing novel light sources.
• Atomic vapors offer unique nonlinear optical properties.
• Two-photon resonance enhances nonlinear processes significantly.

Purpose of the Study:

• To investigate coherent second-harmonic generation in atomic zinc vapor.
• To explore the influence of resonance enhancement on harmonic generation.
• To detect and quantify static electric fields within the atomic vapor.

Main Methods:

• Utilizing two-photon resonance enhancement in atomic zinc vapor.
• Generating coherent second-harmonic radiation at specific wavelengths (1792.5 and 1601 Å).
• Measuring the ratio of second-harmonic to third-harmonic generation to infer electric field strength.

Main Results:

• Successful generation of coherent second-harmonic radiation from 5(1)S(0) and 4(1)D(2) states.
• Detection of static electric fields of approximately 5 kV/cm.
• Attribution of these fields to the ionization of ~2% of atoms in the laser focal volume.

Conclusions:

• Two-photon resonance enhancement is an effective method for generating coherent harmonics in atomic zinc.
• Significant static electric fields are present in the laser-induced plasma, impacting harmonic generation.
• Atomic ionization plays a key role in the observed nonlinear optical phenomena.