Broadband Carrier-Envelope Phase-Controlled Stimulated Ultraviolet Emission from Carbon Dioxide Ions

Area of Science:

• Quantum Optics
• Ultrafast Laser Science
• Molecular Ion Physics

Background:

• Generating coherent broadband ultraviolet (UV) light is crucial for research and industry but remains difficult.
• Existing methods often lack the required control or intensity for advanced applications.

Purpose of the Study:

• To demonstrate a novel method for generating microjoule-level broadband UV emission.
• To explore the control mechanisms of UV emission from molecular ions.
• To develop a simple, high-resolution technique for carrier-envelope-phase (CEP) tagging.

Main Methods:

• Utilizing carrier-envelope-phase (CEP)-stabilized, near-single-cycle ultrashort pulses to ionize carbon dioxide (CO2).
• Driving transitions between excited and ground states of CO2+ ions to produce UV emission (300-450 nm).
• Investigating UV emission seeded by self-phase modulation (SPM) and third-harmonic (TH) generation.

Main Results:

• Achieved microjoule-level UV emission from CO2+ ions.
• Demonstrated that TH-seeded emission is CEP-independent, while SPM-seeded emission is strongly CEP-dependent.
• Observed CEP-dependent UV radiation due to Ramsey-type interference modulating ionic dipole strength.
• Successfully implemented a single-shot CEP tagging technique with high resolution.

Conclusions:

• Established a robust method for generating and controlling broadband UV stimulated emission in molecular ions.
• The CEP-sensitive lasing offers new possibilities for strong-field ionic quantum optics.
• This technique provides a simple and effective way to tag CEP with high precision.