Phase dependence of resonant and antiresonant two-photon excitations

Drescher, L; Witting, T; Kornilov, O; Vrakking, MJJ / PHYSICAL REVIEW A (2022) / DOI: https://doi.org/10.1103/PhysRevA.105.L011101

Overview

Measurements of the phase of two-photon matrix elements are presented for resonant and antiresonant two-color ionization of helium. A tunable, narrow-bandwidth, near-infrared (NIR) laser source is used for extreme ultraviolet (XUV) high-harmonic generation (HHG). The 15th harmonic of the laser is used within (1 + 1’) XUV + NIR two-photon ionization and tuned in and out of resonance with members of the 1snp P-1(1) (n = 3, 4, 5) Rydberg series, covering a broad spectral range with high spectral resolution. The technique allows us to observe characteristic rapid changes in the phase of the two-ph

Key Points

• 1. Excitation scheme & wavelength design
• 2. Pulse energy and delay tuning
• 3. Balancing selectivity and ionization efficiency

Design & Function

• Design: Optimize multistep resonance scheme and optics
• Function: Evaluate ion signal, S/N and resolution
• Feature: Parameter optimization for wavelength/energy/delays

Mini Glossary

• R3PI — Resonance-enhanced three-photon ionization
• REMPI — Resonance-enhanced multiphoton ionization

References

1. PHYSICAL REVIEW A (2022). DOI: https://doi.org/10.1103/PhysRevA.105.L011101

Phase dependence of resonant and antiresonant two-photon excitations

Drescher, L; Witting, T; Kornilov, O; Vrakking, MJJ / PHYSICAL REVIEW A (2022) / DOI: https://doi.org/10.1103/PhysRevA.105.L011101

概要 / Overview

R3PI/REMPI を用いたレーザー分光・イオン化計測の最適化。励起準位設計や波長・パルス条件の最適化により、選択性と感度（S/N）を改善しました。

ここがポイント / Key Points

• 1. 励起スキーム/波長設計
• 2. パルスエネルギー・遅延チューニング
• 3. 選択性とイオン化効率の両立

設計と機能 / Design & Function

• 設計：多段励起（選択則・中間準位）と光学系の最適化
• 機能：イオン信号・S/N・分解能の評価
• 特長：波長/エネルギー/遅延のパラメトリック最適化

用語ミニ解説 / Mini Glossary

• R3PI：共鳴三光子イオン化（Resonance-enhanced three-photon ionization）
• REMPI：共鳴多光子イオン化（Resonance-enhanced multiphoton ionization）

参考文献 / References

1. PHYSICAL REVIEW A (2022). DOI: https://doi.org/10.1103/PhysRevA.105.L011101