SciPost Submission Page
A real-time approach to frequency-mixing spectroscopies: application to sum and difference frequency generation in two-dimensional crystals
by Mike N. Pionteck, Myrta Grüning, Simone Sanna, Claudio Attaccalite
Submission summary
| Authors (as registered SciPost users): | Claudio Attaccalite |
| Submission information | |
|---|---|
| Preprint Link: | scipost_202505_00003v2 (pdf) |
| Date accepted: | Oct. 20, 2025 |
| Date submitted: | Sept. 9, 2025, 12:18 p.m. |
| Submitted by: | Claudio Attaccalite |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approaches: | Theoretical, Computational |
Abstract
We propose a computational framework to extract non-linear response functions from real-time simulations in presence of more than one external field. We apply this approach to the calculation of sum frequency generation (SFG) and difference frequency generation (DFG). SFG and DFG are second-order nonlinear processes where two lasers with frequencies ω1 and ω2 combine to produce a response at frequency ω = ω1 ± ω2 . Compared with other nonlinear responses such as second-harmonic gen eration, SFG and DFG allow for tunability over a larger range. Moreover, the optical response can be enhanced by selecting the two laser frequencies in order to match specific electron-hole transitions. To assess the approach, we calculate the SFG and DFG of two-dimensional crystals, h-BN and MoS2 monolayers, from real-time solution of an effective Schrödinger equation. Within the effective Schrödinger equation, one can select from various levels of theory for the effective one-particle Hamiltonian to account for local-field effects and electron-hole interactions. We compare results obtained within the independent-particle picture and including many-body effects. Such comparison allows us to identify and characterize excitonic features in the obtained spectra. Additionally, we demonstrate that our approach can also extract higher-order response functions, such as field-induced second-harmonic generation. We provide an example using h-BN bilayer.
Author indications on fulfilling journal expectations
- Provide a novel and synergetic link between different research areas.
- Open a new pathway in an existing or a new research direction, with clear potential for multi-pronged follow-up work
- Detail a groundbreaking theoretical/experimental/computational discovery
- Present a breakthrough on a previously-identified and long-standing research stumbling block
Published as SciPost Phys. 19, 129 (2025)
Reports on this Submission
Report #2 by Anonymous (Referee 3) on 2025-9-21 (Invited Report)
- Cite as: Anonymous, Report on arXiv:scipost_202505_00003v2, delivered 2025-09-21, doi: 10.21468/SciPost.Report.11977
Report
Requested changes
There are still a number of minor typographic, spelling, or grammatical issues that should be corrected during the production stage.
A recurrent issue is "$h$-BN bilayer". I believe that there are two grammatically correct variants: either "the $h$-BN bilayer" or "bilayer $h$-BN", but these have slightly different meanings. The authors should decide which one corresponds to their intentions and fix this accordingly. The same is true for "$h$-BN and MoS$_2$ monolayer" on page 11.
There are a few further minor details that are noted in the attached PDF.
Recommendation
Publish (easily meets expectations and criteria for this Journal; among top 50%)
Claudio Attaccalite on 2025-09-09 [id 5800]
Full resubmission letter in attachment
Attachment:
referee_reply.pdf