理论分析振动态H_2~+偶次谐波的辐射机制
|
摘要
理论研究和认证了振动态H_2~+偶次谐波的辐射机制.结果表明,偶次谐波是由于谐波辐射在激光上升和下降区间的不对称效应所产生的.具体来说,在低振动态下,偶次谐波主要来源于激光下降区间.随着振动态增大,来源于激光下降区间的偶次谐波强度减弱;但是,一些来源于激光上升区间的偶次谐波逐渐增强.
The generations of the even-order harmonics from vibrating H_2~+ have been theoretically investigated and identified. The results showed that due to asymmetric harmonic emission(asymmetric half-wave profile) on the rising and the falling parts of the laser field, the even-order harmonics can be generated. In detail, for the case of the lower initial vibrational state, the even-order harmonics mainly come from the falling part of the laser field; while as the initial vibrational state increases, the identified even-order harmonics on the falling part of the laser field decreases; while some other even-order harmonics coming from the rising part of the laser field are gradually enhanced.
The generations of the even-order harmonics from vibrating H_2~+ have been theoretically investigated and identified. The results showed that due to asymmetric harmonic emission(asymmetric half-wave profile) on the rising and the falling parts of the laser field, the even-order harmonics can be generated. In detail, for the case of the lower initial vibrational state, the even-order harmonics mainly come from the falling part of the laser field; while as the initial vibrational state increases, the identified even-order harmonics on the falling part of the laser field decreases; while some other even-order harmonics coming from the rising part of the laser field are gradually enhanced.
引文
[1]Krausz F,Ivanov M.Attosecond physics[J].Rev Mod Phys,2009,81:163.
[2]Feng L Q.Molecular harmonic extension and enhancement from H2+ions in the presence of spatially inhomogeneous fields[J].Phys Rev A,2015,92:053832.
[3]Lu R F,Zhang P Y,Han K L.Attosecond-resolution quantum dynamics calculations for atoms and molecules in strong laser fields[J].Phys Rev E,2008,77:066701.
[4]Corkum P B.Plasma perspective on strong field multiphoton ionization[J].Phys Rev Lett,1993,71:1994.
[5]Lewenstein M,Balcou P,Ivanov M Y,et al.Theory of high-harmonic generation by low-frequency laser fields[J].Phys Rev A,1994,49:2117.
[6]Zuo T,Chelkowski S,Bandrauk A D.Harmonicgeneration by the H2+molecular ion in intense laser fields[J].Phys Rev A,1993,48:3837.
[7]Liu H,Li W L,Feng L Q.Chirp control of multiphoton resonance ionization and charge resonance enhanced ionization on molecular harmonic generation[J].Chem Phys Lett,2017,676:118.
[8]Feng L Q,Chu T S.Nuclear signatures on the molecular harmonic emission and the attosecond pulse generation[J].J Chem Phys,2012,136:054102.
[9]Bian X B,Bandrauk A D.Multichannel molecular high-order harmonic generation from asymmetric diatomic molecules[J].Phys Rev Lett,2010,105:093903.
[10]Kan C,Capjack C E,Rankin R,et al.Spectral and temporal structure in high harmonic emission from ionizing atomic gases[J].Phys Rev A,1995,52:R4336.
[11]Watson J B,Sanpera A,Burnett K.Pulse-shape effects and blueshifting in the single-atom harmonic generation from neutral species and ions[J].Phys Rev A,1995,51:1458.
[12]冯立强.H2+分子双H核对高次谐波辐射的贡献[J].原子与分子物理学报,2018,35:267.
[13]Corso P P,Fiordilino E,Orlando G,et al.Even harmonics from laser driven homonuclear molecules[J].J Mod Opt,2007,54:1387.
[14]Vafaee M,Ahmadi H,Maghari A.Identifying spatially asymmetric high-order harmonic emission in the falling edge of an intense laser pulse[J].J Phys B:At Mol Opt Phys,2017,50:025601.
[15]刘航,李义,姚震,等.利用啁啾场与单极场的组合场驱动He+发射高次谐波[J].四川大学学报:自然科学版,2018,55:118.
[16]刘航,冯立强.利用He+离子链模型增强谐波辐射强度[J].四川大学学报:自然科学版,2018,55:349.
[17]Antoine P,Piraux B,Maquet A.Time profile of harmonics generated by a single atom in a strong electromagnetic field[J].Phys Rev A,1995,51:R1750.
[18]Hu J,Han K L,He G Z.Correlation quantum dynamics between an electron and D2+molecule with attosecond resolution[J].Phys Rev Lett,2005,95:123001.
[2]Feng L Q.Molecular harmonic extension and enhancement from H2+ions in the presence of spatially inhomogeneous fields[J].Phys Rev A,2015,92:053832.
[3]Lu R F,Zhang P Y,Han K L.Attosecond-resolution quantum dynamics calculations for atoms and molecules in strong laser fields[J].Phys Rev E,2008,77:066701.
[4]Corkum P B.Plasma perspective on strong field multiphoton ionization[J].Phys Rev Lett,1993,71:1994.
[5]Lewenstein M,Balcou P,Ivanov M Y,et al.Theory of high-harmonic generation by low-frequency laser fields[J].Phys Rev A,1994,49:2117.
[6]Zuo T,Chelkowski S,Bandrauk A D.Harmonicgeneration by the H2+molecular ion in intense laser fields[J].Phys Rev A,1993,48:3837.
[7]Liu H,Li W L,Feng L Q.Chirp control of multiphoton resonance ionization and charge resonance enhanced ionization on molecular harmonic generation[J].Chem Phys Lett,2017,676:118.
[8]Feng L Q,Chu T S.Nuclear signatures on the molecular harmonic emission and the attosecond pulse generation[J].J Chem Phys,2012,136:054102.
[9]Bian X B,Bandrauk A D.Multichannel molecular high-order harmonic generation from asymmetric diatomic molecules[J].Phys Rev Lett,2010,105:093903.
[10]Kan C,Capjack C E,Rankin R,et al.Spectral and temporal structure in high harmonic emission from ionizing atomic gases[J].Phys Rev A,1995,52:R4336.
[11]Watson J B,Sanpera A,Burnett K.Pulse-shape effects and blueshifting in the single-atom harmonic generation from neutral species and ions[J].Phys Rev A,1995,51:1458.
[12]冯立强.H2+分子双H核对高次谐波辐射的贡献[J].原子与分子物理学报,2018,35:267.
[13]Corso P P,Fiordilino E,Orlando G,et al.Even harmonics from laser driven homonuclear molecules[J].J Mod Opt,2007,54:1387.
[14]Vafaee M,Ahmadi H,Maghari A.Identifying spatially asymmetric high-order harmonic emission in the falling edge of an intense laser pulse[J].J Phys B:At Mol Opt Phys,2017,50:025601.
[15]刘航,李义,姚震,等.利用啁啾场与单极场的组合场驱动He+发射高次谐波[J].四川大学学报:自然科学版,2018,55:118.
[16]刘航,冯立强.利用He+离子链模型增强谐波辐射强度[J].四川大学学报:自然科学版,2018,55:349.
[17]Antoine P,Piraux B,Maquet A.Time profile of harmonics generated by a single atom in a strong electromagnetic field[J].Phys Rev A,1995,51:R1750.
[18]Hu J,Han K L,He G Z.Correlation quantum dynamics between an electron and D2+molecule with attosecond resolution[J].Phys Rev Lett,2005,95:123001.