Journal Article

PUBDB-2025-04769

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Engineering High-Order Harmonic Generation through Gas Confinement at Sub-Millimeter Lengths

Azzolin, A. (Corresponding author)Extern*DESY* ; Giovannetti, G.CFEL*DESY* ; Cannelli, O.CFEL*DESY* ; Guangyu, F.CFEL*DESY* ; Ahsan, M. S.Extern*CFEL*DESY* ; Colaizzi, L.CFEL*DESY* ; Maansson, E.CFEL*DESY* ; Tettenborn, N.Extern*CFEL* ; Oberti, L.DESY* ; Facciala, D.Extern* ; Frassetto, F. ; Ciriolo, A. G. ; Lodi, D. W. ; Ashraf, A. ; Manzoni, C. ; Martínez Vázquez, R. ; Devetta, M.Extern* ; Osellame, R. ; poletto, l.Extern* ; Stagira, S.Extern* ; Vozzi, C.Extern* ; Mullins, T.XFEL.EU*DESY* ; Wanie, V.CFEL*DESY* ; Trabattoni, A.DESY* ; Calegari, F. (Corresponding author)DESY*

2025
IOP Publishing Bristol

This record in other databases:  

Please use a persistent id in citations: doi:10.1088/2515-7647/ae4080  doi:10.3204/PUBDB-2025-04769

Abstract: Attosecond light sources based on high-order harmonic generation (HHG) constitute to date the only table-top solution for producing coherent broadband radiation covering the spectral range from the extreme ultraviolet to the soft X-rays. The so-called emission cutoff can be extended towards higher photon energies by increasing the driving wavelength at the expense of conversion efficiency. An alternative route is to overdrive the process by using higher laser intensities, with the challenging requirement of interacting with higher plasma densities over short propagation distances. Here, we address this challenge by using a differentially pumped glass chip designed for optimal gas confinement over sub-mm lengths. By driving HHG with multicycle pulses at either 800 nm or 1500 nm, we demonstrate a cutoff extension by a factor of two compared to conventional phase matching approaches and surpassing the present record using multicycle fields. Our three-dimensional propagation simulations, in excellent agreement with the experiment, confirm that gas confinement is crucial since efficient phase matching of cutoff harmonics occurs only for short propagation lengths. Additionally, we show that the high photon energy component is not only temporally confined to the leading edge of the driving pulse, but also spatially confined in the near-field to an off-axis contribution due to reshaping of the driving field along propagation inside the medium. Our findings contribute to the fundamental understanding of HHG across different regimes.

---

Contributing Institute(s):

1. Attosecond Science and Technology (FS-ATTO)

Research Program(s):

1. 631 - Matter – Dynamics, Mechanisms and Control (POF4-631) (POF4-631)
2. DFG project G:(GEPRIS)390715994 - EXC 2056: CUI: Tiefe Einblicke in Materie (390715994) (390715994)
3. METRICS - Element-selective impulsive electronic and vibrational spectroscopy of iron-sulfur clusters (101106352) (101106352)
4. DFG project G:(GEPRIS)545611997 - Vermessung von chiralen Transienten von Attosekunden bis Femtosekunden durch ultraschnelle Spektroskopie (545611997) (545611997)
5. SoftMeter - Multi-messenger soft-field spectroscopy of molecular electronics at interfaces (101076500) (101076500)

Experiment(s):

1. No specific instrument

Appears in the scientific report 2025

---

Database coverage:
; ; ; ; Article Processing Charges ; Clarivate Analytics Master Journal List ; DOAJ Seal ; Emerging Sources Citation Index ; Fees ; IF < 5 ; JCR ; SCOPUS ; Web of Science Core Collection

---