English translation of the paper "Electromagnetic field inside a plane-parallel layer in the resonant absorption regime" (1962) by A. P. Khapalyuk: Pioneering study on coherent perfect absorption

Denis V. Novitsky

REVIEW 2 major objections 5 minor 27 references

English translation of the paper "Electromagnetic field inside a plane-parallel layer in the resonant absorption regime" (1962) by A. P. Khapalyuk: Pioneering study on coherent perfect absorption

T0 review · 2 major / 5 minor · reviewed 2026-08-05 · deepseek-v4-flash

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Pith's one-line read This paper argues that a 1962 article by A. P. Khapalyuk, presented here in its first English translation, already derived the conditions for coherent perfect absorption, moving the concept's discovery almost five decades earlier than usual

desk verdict A faithful-looking translation of a 1962 CPA precursor; the math checks out, but the historical claim rests on unverified translation fidelity and an undocumented 'first translation' assertion. read the letter →

arxiv 2508.19687 v1 pith:TJ65DH3T submitted 2025-08-27 physics.hist-ph physics.optics

Denis V. Novitsky This is my paper · ORCID

classification physics.hist-phphysics.optics

keywords coherentperfectabsorptionresonantplane-parallellayerinterferencehistoryofopticsanti-lasingKhapalyuk

verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

This paper presents the first English translation of A. P. Khapalyuk's 1962 article on 'resonant absorption' in a plane-parallel layer and argues that this article is the first study of what is now called coherent perfect absorption (CPA), the total absorption of two coherent counter-propagating waves by a lossy medium. The translated derivation shows that total absorption occurs when the layer thickness and refractive index satisfy two conditions: e^{-4kκl}=r1 r2 for amplitude matching and 2kn1l=2πs−ρ1−ρ2 for phase matching, which together make the layer absorb all incoming light and emit no outgoing waves. If the author is right, the core CPA concept was published in 1962 rather than in 2010, and this translation makes that derivation accessible to an English-speaking audience for the first time. The paper also places the result in the context of later CPA work and the earlier Borrmann effect.

What carries the argument

The key object is the plane-wave solution of Maxwell's equations for a single plane-parallel lossy layer: two coherent waves incident from both sides and two internal counter-propagating waves, with no waves leaving the layer. Substituting these fields into the boundary conditions that require continuity of tangential electric and magnetic components gives a homogeneous linear system whose nonzero solution requires the determinant to vanish. That determinant condition splits into the amplitude and phase matching equations (4), which are the mechanism that converts the absorption problem into a condition on layer thickness, refractive index, and the Fresnel reflection coefficients r1, r2 and

What would settle it

Locate the original Russian text and verify that equations (4) and the zero-outgoing-wave boundary condition are rendered as in this translation; then run a two-beam absorption experiment on a single lossy slab at the predicted thickness and refractive index. If the original equations differ, or if measurable outgoing power remains, the priority claim and its equivalence to modern CPA would be undermined.

Watch

Extended reading notes

Core claim

The central claim is that Khapalyuk's 1962 paper contains the first derivation of coherent perfect absorption. By solving Maxwell's equations for a single absorbing slab with two coherent waves incident from opposite sides and requiring that no waves leave the layer, Khapalyuk obtains the amplitude condition e^{-4kκl}=r1 r2 and the phase condition 2kn1l=2πs−ρ1−ρ2, where r1 and r2 are the Fresnel reflection coefficients at the two boundaries and ρ1 and ρ2 are the corresponding phase shifts. These are precisely the conditions under which all incident power is absorbed in the layer. The present author argues that this is the same physical situation as modern CPA, gives the first English transla

Load-bearing premise

The identification of the 1962 article with modern CPA rests on the English translation being a faithful rendering of the Russian original and on interpreting 'no waves leaving the layer' as total absorption; the preprint does not include the original text for comparison.

Editorial extensions

If this is right

If accepted, the discovery date of coherent perfect absorption moves from 2010 back to 1962, making Khapalyuk's 'resonant absorption' the first published account.
The translated conditions give a simple, exact recipe: for a given transparent surrounding medium, one can choose layer thickness and complex refractive index to achieve total absorption of coherent two-sided illumination without any structured or periodic medium.
The derivation's zero-outgoing-wave condition is equivalent to the modern picture of CPA as a scattering zero at a real frequency; what is genuinely new after 1962 is the scattering-pole/zero framework, not the absorption condition itself.
The paper supports the argument that 'resonant absorption' is an older and arguably more accurate name than 'coherent perfect absorption,' since CPA also abbreviates chirped pulse amplification.
The historical connection places CPA in a lineage that includes the Borrmann effect in X-ray physics, so the same phenomenon has had several independent formulations under different names.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

A direct extension would be to re-derive equations (4) in scattering-matrix language and show that they correspond exactly to a scattering zero at a real frequency; if that mapping holds, the 1962 paper fully anticipates the mathematical core of modern CPA.
The translated formulas suggest a concrete modern experiment: illuminate a single lossy slab at normal incidence with two phase-locked beams and scan thickness or refractive index to observe zero outgoing power, which would make the historical claim physically testable today.
If the priority claim is accepted, standard historical reviews of non-Hermitian photonics may need to credit an earlier Soviet-era derivation, with 2010 work credited for popularizing the concept and adding the scattering-zero interpretation.
The symmetric equal-medium formulas, involving cosh and sinh terms, hint that the same conditions could be recast as an impedance-matching problem, the language commonly used to describe CPA today; checking this equivalence is a natural next step.

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Signed reviews

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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Desk Editor's Note

read the letter

This is a useful translation job, not new physics. Khapalyuk's 1962 derivation, as rendered here, is internally consistent and does reproduce the two-beam coherent perfect absorption conditions: equations (4) reduce correctly to the amplitude and phase matching conditions, and the determinant treatment is sound. The introductory remarks are honest in crediting Rosanov's earlier priority observation, and the biographical material is a nice touch. The paper's real value is making a historically interesting derivation accessible to an English-speaking audience.

The soft spots are exactly where the reader's report puts them. The manuscript gives no original Russian text and no scan, so the fidelity of the translation is not independently checkable. The 'first English translation' claim is asserted without documenting a search of databases or catalogs. These are addressable additions rather than fatal flaws, and I would not treat them as grounds for rejection if the author can supply the source text and a brief statement of the search. The identification with CPA is interpretive but reasonable: Khapalyuk's 'resonant absorption' really is the same two-sided coherent illumination problem, and the paper itself is suitably cautious with 'can be considered.'

The citation pattern looks fine: the author relies on Rosanov's published note for the priority claim, not on self-citations, and the self-citations in the context section are relevant to the modern CPA trends being surveyed. The paper does not overreach; it states clearly that Chong et al. added the scattering-zero framework, which is the genuinely new modern element.

In short: this is a solid contribution to the historiography of CPA and a useful teaching text. It deserves serious peer review, with the expectation that the author adds the original text or scan and documents the search for prior translations. I would not cite it in my own work unless I were writing specifically about CPA history, but it is a reasonable addition to a reading group on the prehistory of non-Hermitian photonics.

Referee Report

2 major / 5 minor

Summary. The manuscript presents an English translation of A. P. Khapalyuk's 1962 Doklady Akademii Nauk BSSR paper on 'resonant absorption' in a plane-parallel lossy layer, arguing that this work 'can be considered as a first study' of coherent perfect absorption (CPA). The translation is preceded by biographical and contextual remarks and followed by Khapalyuk's derivation: solving Maxwell's equations with a no-outgoing-waves boundary condition leads to determinant condition (3), equivalent to the two real conditions (4), e^{-4kκl}=r1r2 and 2kn1l=2πs−ρ1−ρ2, together with expressions for the internal fields, energy density, Poynting vector, and absorption. The historical claim is explicitly qualified as 'can be considered' and is supported by N. N. Rosanov's earlier note [3] plus the self-contained translated derivation.

Significance. If the historical claim holds, this is a significant finding for the history of optics: the core CPA idea—total absorption of two coherent counter-propagating waves by a lossy layer—would be published in 1962, almost five decades before the standard attribution to Chong et al. (2010). The translated mathematics is internally consistent and parameter-free; I verified that the determinant reduction from Eq. (3) to Eq. (4) reproduces the standard CPA amplitude and phase conditions without any fitted parameters. The paper also adds useful context by connecting the effect to the Borrmann effect and modern CPA-lasing / virtual-absorption developments. The main vulnerability is not the derivation but the unverified translational and bibliographic premises on which the priority claim rests.

major comments (2)

[Abstract and §2 (Translation)] The claim that this is the 'first translation' and that it faithfully represents Khapalyuk's 1962 original is load-bearing for the paper's central historical conclusion, but the manuscript provides no original Russian text, facsimile, or archival link, and no statement of translation policy or notation-modernization choices. Since the identification with CPA depends on equations (1)–(4) being exactly Khapalyuk's, please add a supplemental file with the original Russian text (or a stable scan/URL) and a note describing how the translation handles notation, equation numbering, and terminology. Without this, the referee cannot verify the translation fidelity that the priority claim requires.
[Abstract and §1] The assertion 'we give the first English translation' is undocumented. No bibliographic search is described (e.g., Google Scholar, WorldCat, zbMATH, MathSciNet, Scopus, or citation databases), so the 'first translation' claim cannot be checked. Please either document the search or qualify the claim as 'to the best of our knowledge'; the latter would be appropriate given the difficulty of proving a negative for a 1962 Russian-language paper.

minor comments (5)

[Eq. (1)] The magnetic-field labels for the third and fourth waves are both written as H2; they should be H3 and H4.
[Eqs. (1) and (2)] The phase convention for E4 is confusing: Eq. (1) includes a factor e^{ikn2l} in the z=l field, but Eq. (2) uses E4 without this factor. Clarify whether E4 denotes the field amplitude at the boundary or the coefficient E0_4.
[Eq. (5a)] The arctangent branch is given as 0≤ρ_j≤π, but arctan alone is undefined in the second quadrant. Specify the quadrant rule explicitly (e.g., atan2 with numerator 2n_jκ and denominator n_j^2−n1^2−κ^2).
[§1.1] Minor wording: '3 Doctor and 13 Candidate dissertations' should be '3 Doctor of Sciences and 13 Candidate of Sciences dissertations' or similar.
[Translation footnote 1] The reference to Khapalyuk's 1960 paper in Inzhenerno-Fizicheskii Zhurnal gives only issue 3; add volume and pages if available.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the translated 1962 derivation is self-contained and the CPA-priority claim rests on an external historical comparison, not on fitted parameters or self-citations.

full rationale

The translated paper derives the resonant-absorption conditions from Maxwell's equations and boundary conditions with no outgoing waves: equations (1)-(2) define the plane-wave ansatz and continuity conditions, equation (3) is the determinant-zero condition for a nontrivial solution, and equation (4) separates it into amplitude and phase conditions e^{-4kκl}=r1r2 and 2kn1l=2πs−ρ1−ρ2. This is a self-contained boundary-value derivation, not a fitted parameter restated as a prediction. The identification with coherent perfect absorption is made by comparing these derived zero-scattering conditions with the later Chong et al. formulation and by citing Rosanov's independent historical note [3]; the author's own publications [18,19,25] appear only as examples of modern CPA trends and are not load-bearing for the priority claim. The remaining concerns—fidelity of the translation and the undocumented 'first translation' assertion—are source-critical and bibliographic issues, not circularity in the derivation chain. Therefore no circular step meets the evidentiary standard.

Assumptions & free parameters 0 free parameters · 5 assumptions · 0 invented entities

No free parameters are fitted; Eq. (4) relates physical parameters of the layer. The translated derivation assumes Maxwell's equations, plane-wave fields, and standard boundary conditions. The historical claim assumes translation fidelity and the interpretive equivalence between 'resonant absorption' and modern CPA. No new entities are postulated.

assumptions (5)

standard math Maxwell's equations and continuity of tangential E and H at layer boundaries
The translated derivation (Eqs. (1)-(2)) uses these without proof.
domain assumption Field configuration consists of four monochromatic plane waves with no outgoing waves in the outer media
This defines the resonant absorption / CPA setup in the opening paragraph and Eq. (1).
domain assumption The layer is described by a complex refractive index n1 - iκ with positive κ
Needed for absorption and for conditions (4); standard passive-medium assumption.
domain assumption The English translation faithfully represents the 1962 Russian original
The whole historical claim depends on it; the original is not included for comparison.
domain assumption Khapalyuk's 'resonant absorption' is identified with modern CPA
The paper asserts this equivalence based on the translated formulas and Rosanov [3]; it is an interpretive judgment rather than a theorem.

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Cite this review

Pith. "Pith review of English translation of the paper "Electromagnetic field inside a plane-parallel layer in the resonant absorption regime" (1962) by A. P. Khapalyuk: Pioneering study on coherent perfect absorption." pith.science (2026). https://pith.science/paper/TJ65DH3T

@misc{pith2026250819687,
  author       = {Pith},
  title        = {Pith review of: English translation of the paper "Electromagnetic field inside a plane-parallel layer in the resonant absorption regime" (1962) by A. P. Khapalyuk: Pioneering study on coherent perfect absorption},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/TJ65DH3T}},
  note         = {Machine review of arXiv:2508.19687}
}

read the original abstract

In 1962, Belarusian physicist A. P. Khapalyuk has published the paper [Doklady Akademii nauk BSSR, volume 6, issue 5, pages 301-304] devoted to the effect of resonant absorption of light in a layer of matter. This work can be considered as a first study of the phenomenon known today as coherent perfect absorption (CPA). Unfortunately, the paper by A. P. Khapalyuk was published in a local journal in Russian and is almost unknown to the English-language scientific community. Here, we give the first translation of this paper into English, accompany it with the introductory remarks including some biographical information on A. P. Khapalyuk and put it in the context of modern CPA studies.

Figures

Figures reproduced from arXiv: 2508.19687 by the authors.

**Figure 1.** plane and increasing in the direction from the 0th medium to the 2nd one; l is the layer thickness. Substituting (1) into the boundary conditions requiring continuity of the tangential components of electric and magnetic vectors at both layer boundaries, we have (n1 − iκ)E 0 2 e −kκl−ikn1l − (n1 − iκ)E 0 3 e kκl+ikn1l + n2E4 = 0, E 0 2 e −kκl−ikn1l + E 0 3 e kκl+ikn1l − E4 = 0, n0E 0 1 − (n1 − iκ)E 0 2 + (n1 − iκ)E… view at source ↗

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

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2025

Pith tools

Reviewed August 5, 2026 · model on record in the stance chip above.

[1] [3]

N. N. Rosanov, Antilaser: resonance absorption mode or coherent per- fect absorption?, Physics Uspekhi 60, 818 (2017)

work page 2017

[2] [1]

D. G. Baranov, A. Krasnok, T. Shegai, A. Al` u, and Y. Chong, Coherent perfect absorbers: linear control of light with light, Nature Reviews Materials 2, 17064 (2017)

work page 2017

[3] [2]

Y. D. Chong, L. Ge, H. Cao, and A. D. Stone, Coherent Perfect Ab- sorbers: Time-Reversed Lasers, Physical Review Letters 105, 053901 (2010)

work page 2010

[4] [4]

https://poisk.re/person/officers/9110095 (in Russian)

work page arXiv

[5] [6]

B. I. Stepanov, A Universal Relation Between the Absorption and Lu- minescence Spectra of Complex Molecules, Soviet Physics Doklady 2, 81 (1957)

work page 1957

[6] [7]

1, issue 2, 92 (2000, in Russian); https://elib.bsu.by/handle/123456789/195075

Alexander Petrovich Khapalyuk, Vestnik BSU, ser. 1, issue 2, 92 (2000, in Russian); https://elib.bsu.by/handle/123456789/195075

arXiv 2000

[7] [8]

A. M. Bel’skii, T. M. Korneichik, A. P. Khapalyuk. Spatial structure of laser radiation (Minsk, BSU, 1982, in Russian)

work page 1982

[8] [9]

https://kb.brl.by/index.php/heritage/item/786-13-sakavika-2015-g- 90-gadou-z-dnya-naradzhennya-alyaksandra-pyatrovicha-khapalyuka- 1925-belaruskaga-vuchonaga-fizika-autara-prats-pa-fizichnaj-optytsy-i- lazernaj-fizitsy (in Belarusian)

work page 2015