{"id":"a68c78bb-309b-4315-8e00-6764153a17c6","arxiv_id":"2607.11037","paper_version":1,"verdict":"ACCEPT","confidence":"HIGH","novelty_score":7.0,"correctness_risk":"low","formal_verification":"none","parameter_count":1,"one_line_summary":"Polarization-resolved THG-CD in chiral (R/S-MBACl)2PbI4 yields hidden dissymmetry factors exceeding 1.9 for telecom-band CPL discrimination, with opposite signs in orthogonal THG channels that cancel in total intensity.","lead":"Researchers show that a chiral 2D perovskite converts telecom infrared light into visible light while strongly distinguishing left- from right-circular polarization via third-harmonic generation. Polarization-resolved detection uncovers giant hidden circular dichroism (g-factors >1.9) that cancels in ordinary total-intensity measurements, enabling anti-counterfeiting and optical encoding at communication wavelengths.","discovery_kind":"new_application","skeptic_critique":{"model":"grok-4.5","headline":"No significant objection identified","rationale":"The paper’s strongest claim is an experimental fact about polarization-resolved intensities, not a microscopic tensor model. The data, controls (racemic and PEA crystals, power dependence, wavelength scan), and methods are sufficient to establish opposite-signed, near-maximal g-factors in the two linear channels and their mutual cancellation in the total signal. The SI S4 interference condition is a plausible post-hoc explanation for why |g| can approach 2 and why CPL is converted into nearly pure linear THG, but the claim does not rest on that idealization being proven for every independent χ(3) element. Consequently the reader’s weakest-assumption note is correctly identified as non-load-bearing for acceptance. No internal inconsistency or missing control that would overturn the measured effect is apparent; the usual experimental caveats (crystal quality, full tensor determination) are already acknowledged. Verdict remains ACCEPT.","tokens_in":15458,"tokens_out":532,"duration_ms":5022,"concrete_test":"Independently re-measure one R-SC crystal that shows near-zero total gTHG-CD (as in Fig. 4a) under identical QWP rotation, extracting both x- and y-polarized THG intensities at the excitonic peak; confirm that |gx| and |gy| still exceed 1.9 with opposite signs and that the Stokes S1 under pure CPL remains >0.95. If this fails, the hidden-giant claim weakens; if it holds, the experimental core is robust.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim is the experimental observation that orthogonal THG polarization channels in (R/S-MBACl)2PbI4 single crystals carry opposite-signed THG-CD responses with |g| exceeding 1.9 that largely cancel in the total intensity. This is directly supported by the QWP-rotation data (Figs. 3–4, S4–S7), power-law checks, enantiomer and racemic/achiral controls, and wavelength dependence near excitonic resonance. The reader’s weakest assumption (ideal equal-amplitude, ±π/2 interference of the effective tensor combinations) is only an interpretive inference drawn after the fact in SI S4; it is not required for the measured polarization-resolved g-factors or the cancellation phenomenology to stand. Sample-to-sample variation and incomplete full-tensor determination are already noted by the authors and do not undermine the reported intensities.","agreement_with_reader":"agree"},"referee_report":{"model":"grok-4.5","summary":"The manuscript reports third-harmonic generation circular dichroism (THG-CD) in the chiral 2D halide perovskite (R/S-MBACl)2PbI4, enabling CPL discrimination at telecom-band fundamental wavelengths (roughly 1440–1650 nm) with conversion into the visible. Polarization-resolved QWP-rotation measurements show that the x- and y-polarized THG channels carry opposite-signed THG-CD responses; these largely cancel in the total (unpolarized) intensity, so conventional total-THG g-factors underestimate the intrinsic anisotropy. When the channels are separated, |g| values exceeding 1.9 are obtained, and the sign of the giant response can be switched by analyzer selection without enantiomer inversion. Power-law cubic dependence, excitonic resonance enhancement, enantiomer reversal, and racemic/achiral controls support the claim. An anti-counterfeiting concept based on the hidden polarization-resolved response is sketched.","tokens_in":15675,"tokens_out":992,"duration_ms":8909,"significance":"Third-order chiral NLO responses in molecular/hybrid materials remain sparsely explored relative to SHG-CD. Demonstrating telecom-band CPL discrimination via THG, together with the concrete experimental finding that opposite-signed giant g-factors hide in orthogonal linear polarization channels, is a clear advance. The result is of interest for chiral nonlinear optics, wavelength-converted CPL sensing, and optical anti-counterfeiting. Strengths include systematic power, wavelength, enantiomer, and control measurements, and an explicit statement that total-intensity g-factors can mask the material response. The interpretive tensor analysis (equal-amplitude, ±π/2 interference) is secondary and does not underwrite the measured intensities.","major_comments":[{"comment":"The central experimental claim (opposite-signed polarization-resolved THG-CD with |g| > 1.9 that cancel in total intensity) is well supported by Figs. 3–4 and S4–S7. No load-bearing technical correction is required for that claim. Sample-to-sample variation in total g is already acknowledged with error bars (Fig. 2b); the near-ideal interference condition in SI S4 is correctly presented as an inference from the observed |g|≈2 and polarization conversion, not as an independent measurement of every tensor element.","section":null}],"minor_comments":[{"comment":"Notation for the dissymmetry factor is inconsistent across the text and figures (gTHG-CD, g%&'!(), g,,%&'!(), gx,THG-CD, etc.). Standardize to a single form (e.g., g_THG-CD^x, g_THG-CD^y, g_THG-CD^tot).","section":null},{"comment":"Figure 1 caption refers to panels (d, e) for MoS2 comparisons, while the body text also cites “Figure 2e” for the bulk-crystal comparison; renumber or correct the cross-reference.","section":null},{"comment":"SI S3: the effective χ^(3) extraction relative to MoS2 is useful; state the refractive-index and absorption values (or literature sources) used for the perovskite more explicitly so the factor 0.04 can be reproduced.","section":null},{"comment":"Table S1 is referenced for Fourier coefficients but the numerical entries are not fully visible in the provided text; ensure the published SI includes the complete coefficient table for both enantiomers.","section":null},{"comment":"A brief quantitative estimate of absolute THG conversion efficiency (or photons/s under stated power and focusing) would help readers judge practical utility for the proposed telecom detection and anti-counterfeiting schemes.","section":null},{"comment":"Minor typos: “roll” → “role” (Introduction); “2-phenylehtylamine” → “2-phenylethylamine” (Materials); occasional missing spaces around units and g-factor symbols.","section":null}],"recommendation":"accept","confidential_remarks":"The work is solid experimental materials physics with a clear, reproducible central observation. Fit for a high-quality materials/optics journal is good. The anti-counterfeiting application is conceptual rather than demonstrated; that is acceptable if framed as outlook. No novelty or citation concerns of note."},"author_rebuttal":null,"desk_editor":{"model":"grok-4.5","letter":"The real result here is experimental and clean: in (R/S-MBACl)2PbI4 single crystals, the x- and y-polarized THG channels carry opposite-signed THG-CD with |g| values that reach ~1.9 and largely cancel when you just measure total intensity. That cancellation is why conventional total-THG g-factors look modest, and polarization-resolved detection recovers the giant response without flipping the enantiomer. They also push the fundamental into the telecom band and convert it to visible light, which SHG-CD work in the same materials family has not done.\n\nWhat they do well is the measurement package. Cubic power dependence, spectral match to the excitonic peak, QWP rotation curves for both enantiomers, racemic and (PEA)2PbI4 controls that stay near zero even when polarization-resolved, and wavelength dependence that collapses off resonance. Sample-to-sample scatter in the total g is acknowledged and averaged with error bars. The anti-counterfeiting sketch (hidden chiral signature only appears after an analyzer) is a natural extension of the data rather than a stretch.\n\nSoft spots are real but secondary. Full third-order tensor extraction is incomplete; the |A|=|B| and ΔΦ=±π/2 story in the SI is a post-hoc inference that explains why |g| can approach 2, not a load-bearing claim. Crystal quality and thickness still move the numbers. Thin-film data are weaker and more isotropic, as expected for polycrystals. None of that undercuts the measured polarization-resolved intensities or the cancellation phenomenology.\n\nThis is for people working on chiral NLO, hybrid perovskites, or telecom-band chiroptical devices. The math is standard Jones/Fourier fitting; the citations cover the SHG-CD and metamaterial THG literature fairly. I would send it to referees. It is a clear experimental advance on a sparsely explored third-order chiral effect, not a foundational rewrite, but the data justify the space.","headline":"Solid experimental report of opposite-signed, near-maximal THG-CD in orthogonal polarization channels of a chiral 2D perovskite that cancel in total intensity, giving telecom-band CPL discrimination plus a simple anti-counterfeiting idea.","tokens_in":16277,"tokens_out":528,"would_cite":true,"duration_ms":8499,"reading_group":"yes","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"grok-4.5","headline":"Polarization-resolved third-harmonic generation in a chiral 2D perovskite uncovers opposite-signed circular dichroism in orthogonal channels that cancel in total intensity, yielding dissymmetry factors above 1.9 and telecom-band circular-li","keywords":["chirality","third-harmonic generation","circular dichroism","two-dimensional halide perovskite","telecom-band detection","nonlinear optics","anti-counterfeiting","polarization-resolved detection"],"falsifier":"Repeat the polarization-resolved THG measurement on the same crystals but detuned well away from the excitonic resonance (or on crystals of identical structure but suppressed excitonic oscillator strength); if the giant opposite-signed g-factors collapse while total THG remains finite, the interference premise fails.","tokens_in":16399,"feed_emoji":"🔬","tokens_out":650,"duration_ms":5366,"temperature":0.7,"pith_summary":"The paper shows that third-harmonic generation (THG) from the chiral two-dimensional perovskite (R/S-MBACl)2PbI4 can discriminate the handedness of circularly polarized light at telecom wavelengths and convert the signal into the visible. Conventional total-intensity THG circular dichroism underestimates the material’s intrinsic response because the x- and y-polarized THG components carry opposite chiral signatures that largely cancel. When those channels are separated with a polarizer, dissymmetry factors exceed 1.9 in magnitude—nearly the theoretical maximum—and the sign of the giant response can be switched simply by choosing the output polarization, without any structural enantiomer inversion. The effect is strongest under excitonic resonance and is absent in racemic or achiral analogues. The result both supplies a practical route for telecom-band circular-light detection and demonstrates that polarization-resolved analysis is required to reveal the true strength of chiral third-order nonlinear optics.","feed_headline":"Hidden giant THG circular dichroism exceeds 1.9 in chiral perovskite","feed_subtitle":"Orthogonal polarization channels cancel in total intensity; a polarizer unlocks either handedness at telecom wavelengths","key_machinery":"Polarization-resolved THG-CD: the intensity difference between left- and right-circular fundamental light measured separately in the x- and y-linear THG channels (governed by independent third-order tensor combinations), which cancel when summed but each approach |g| ≈ 2 under excitonic resonance.","core_discovery":"In (R/S-MBACl)2PbI4 single crystals the orthogonally polarized THG channels exhibit opposite-signed THG circular dichroism; these contributions cancel in the total intensity, masking giant dissymmetry factors |g| > 1.9 that become accessible only under polarization-resolved detection and allow selective extraction of either handedness without structural chiral inversion.","pith_inferences":[],"forward_implications":[],"fun_headline_variants":["Polarization unlocks |g| > 1.9 THG-CD hidden in chiral perovskite","Opposite THG channels cancel, masking giant chirality at telecom band","Polarizer reveals |g| exceeding 1.9 in 2D perovskite THG circular dichroism","Hidden THG-CD anisotropy yields g-factors over 1.9 without inversion","Orthogonal polarizations hide giant THG-CD in chiral 2D perovskite"],"cache_read_input_tokens":128,"weakest_assumption_plain":"The near-maximal dissymmetry factors are taken to mean that the symmetric and chiral-asymmetric third-order tensor combinations have equal amplitudes and a relative phase of roughly ninety degrees, an interference condition inferred from the data rather than measured element-by-element.","fun_headline_variants_meta":{"raw":{"variants":["Polarization unlocks |g| > 1.9 THG-CD hidden in chiral perovskite","Opposite THG channels cancel, masking giant chirality at telecom band","Polarizer reveals |g| exceeding 1.9 in 2D perovskite THG circular dichroism","Hidden THG-CD anisotropy yields g-factors over 1.9 without inversion","Orthogonal polarizations hide giant THG-CD in chiral 2D perovskite"]},"model":"grok-4.5","effort":"low","cost_usd":0.004762,"raw_usage":{"total_tokens":1407,"prompt_tokens":824,"num_sources_used":0,"completion_tokens":96,"cost_in_usd_ticks":47620000,"prompt_tokens_details":{"text_tokens":824,"audio_tokens":0,"image_tokens":0,"cached_tokens":256},"completion_tokens_details":{"audio_tokens":0,"reasoning_tokens":487,"accepted_prediction_tokens":0,"rejected_prediction_tokens":0}},"tokens_in":824,"tokens_out":96,"duration_ms":4514,"temperature":1.0,"reasoning_tokens":487,"cache_read_input_tokens":256,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-07-14T07:28:28.730893+00:00","model_set":{"reader":"grok-4.5"},"falsifier":"Repeat the polarization-resolved THG measurement on the same crystals but detuned well away from the excitonic resonance (or on crystals of identical structure but suppressed excitonic oscillator strength); if the giant opposite-signed g-factors collapse while total THG remains finite, the interference premise fails.","supporting_citations":[],"review_version":1}