pith. sign in

arxiv: 2604.06634 · v1 · submitted 2026-04-08 · ⚛️ physics.optics

UV-enhanced SEM: towards orientation and electron work function imaging

Maciej Kretkowski , Haoran Mu , Hsin-Hui Huang , Krishna Prasad Khakurel , Lukita Sari Ikhsan , Yu Masuda , Saulius Juodkazis , Wataru Inami
show 1 more author
Yoshimasa Kawata
This is my paper

Pith reviewed 2026-05-10 18:31 UTC · model grok-4.3

classification ⚛️ physics.optics
keywords UV-enhanced SEMdeep-UV illuminationsecondary electron emissionwork function imagingsurface orientation contrastpolarization controlscanning electron microscopyin-situ illumination
0
0 comments X

The pith

Deep-UV tilted illumination inside an SEM enables coating-free imaging of surface orientation and electron work function.

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

The paper develops a practical instrument that shines deep-ultraviolet light at 250 nm onto a sample while it is imaged in a scanning electron microscope. External mechanisms outside the vacuum chamber control the light source's lateral position, tilt angle up to 6.5 degrees from a 42-degree baseline, and the plane of a linear polarizer. This setup modulates the tangential and normal electric-field components at the surface to steer and increase secondary-electron emission in chosen directions. The authors show through modeling that the field enhancement should produce observable contrast tied to crystal orientation or local work function. No metal coating is required, so the same specimen remains available for later measurements.

Core claim

Deep-UV ~250 nm (4.96 eV) tilted in-situ co-illumination of the sample under SEM imaging is implemented with external mechanical control of LED position and tilt, plus an adjustable linear polarizer for s-polarized light; numerical modeling confirms the resulting E-field enhancement supports directional secondary-electron emission from uncoated surfaces, opening orientation and work-function contrast modes.

What carries the argument

External mechanical control of UV-C LED position and tilt combined with an adjustable linear polarizer that tunes tangential and normal electric-field components at the sample surface.

If this is right

  • Secondary-electron emission can be directed and enhanced by tuning the incident polarization and angle without metal coatings.
  • New contrast mechanisms become available for mapping surface orientation and local electron work function in the SEM.
  • Sample integrity is preserved, allowing the same specimen to undergo subsequent non-SEM analyses.
  • Linearly polarized UV-C light with azimuthal control in the (s,p) plane is feasible and can be modeled for optimized emission.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The method could be adapted to map work-function variations across heterogeneous or polycrystalline materials at nanoscale resolution.
  • Polarization tuning might permit selective enhancement of emission from specific surface states or crystal faces.
  • Integration into routine SEM workflows would shorten sample-preparation time for beam-sensitive or coating-intolerant specimens.
  • Further wavelength or angle optimization could improve contrast selectivity for particular classes of inorganic or organic surfaces.

Load-bearing premise

External mechanical adjustments of the UV source position and tilt can be performed without breaking vacuum integrity or degrading SEM image resolution, and the modeled field enhancements will produce measurable gains in secondary-electron yield or directional contrast.

What would settle it

A side-by-side comparison of secondary-electron images acquired with and without the UV illumination, showing either no increase in yield or no new orientation-dependent contrast features while the vacuum and beam resolution remain unchanged.

Figures

Figures reproduced from arXiv: 2604.06634 by Haoran Mu, Hsin-Hui Huang, Krishna Prasad Khakurel, Lukita Sari Ikhsan, Maciej Kretkowski, Saulius Juodkazis, Wataru Inami, Yoshimasa Kawata, Yu Masuda.

Figure 1
Figure 1. Figure 1: FIG. 1. Technical implementation of the deep-UV module combined with SEM (FE Jeol 7001). (a) [PITH_FULL_IMAGE:figures/full_fig_p003_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. Cross section of the UV LED illumination end-effector assembly. Focusing lens was added [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. (a) Electrical connector block for a feed-through with 3 electrical contact pins within 12- [PITH_FULL_IMAGE:figures/full_fig_p004_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4. Complete assembly: (a) UV beam and e-beam delivery and detection parts inside SEM [PITH_FULL_IMAGE:figures/full_fig_p005_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: FIG. 5. (a) Cross sectional view of UV-C focused beam with indicated location for 10-mm-diameter [PITH_FULL_IMAGE:figures/full_fig_p006_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: shows light intensity distribution in the (x,y)-plane and for the normal to it |Ez| 2 component. Finite difference time domain (FDTD, Lumerical, Ansys) was used for the nor￾mal incidence to demonstrate specific light intensity enhancement for the normal to the interface E-field component E(n) . Depending on the orientation of the sample (e.g., placed on rotational stage), different sides of the Si and Ta n… view at source ↗
read the original abstract

Deep-UV ~ 250 nm (4.96 eV) tilted in-situ co-illumination of the sample under imaging by scanning electron microscope (SEM) is developed at a robust and practical instrument level. Precise mechanical control of the lateral position and tilt angle (within 6.5$^\circ$ from a 42$^\circ$ baseline) of the UV-C LED source is achieved using mechanisms external to the vacuum chamber. The incorporated linear polariser (for s-pol. mode illumination) with external polarisation plane adjustment allows for modulation and tuning of tangential $E^{(t)}$ and normal $E^{(n)}$ electric field components and their enhancement for controlled directional electron emission from the surface of the sample. Numerical modelling of E-field enhancement corroborates the expected enhancement in the production of secondary electrons. This modality of SEM imaging does not require metal coatings, preserving sample integrity for subsequent analysis. The feasibility of having linearly polarised incident UV-C light with azimuthal orientation control in $(s,p)$-plane is modeled and discussed.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 1 minor

Summary. The manuscript describes the development of an in-situ deep-UV (~250 nm) co-illumination system for SEM, featuring external mechanical controls for LED lateral position and tilt (within 6.5° of a 42° baseline) plus an adjustable linear polarizer for s-polarized illumination. Numerical modeling of tangential and normal E-field components is presented to support expected enhancement of secondary electron yield, enabling potential orientation and work-function contrast imaging without metal coatings.

Significance. If the modeled E-field enhancements translate to measurable imaging gains, the external-control architecture could offer a practical, non-destructive SEM modality for surface characterization. The emphasis on vacuum-compatible external mechanisms is a clear engineering strength that addresses integration challenges.

major comments (2)
  1. [Abstract] Abstract and modeling discussion: the central claim that numerical E-field modeling 'corroborates the expected enhancement in the production of secondary electrons' and enables a 'new modality of SEM imaging' is unsupported by any experimental secondary-electron yield data, image contrast measurements, or polarization-dependent results; no test-sample images under 250 nm s-polarized illumination versus baseline are shown.
  2. [Instrument description] The manuscript asserts that external mechanical control of UV-C LED position and tilt 'is achieved' at a 'robust and practical instrument level' without compromising SEM performance, yet provides no vacuum-integrity tests, imaging-resolution comparisons, or interference data to substantiate this load-bearing assumption for the proposed modality.
minor comments (1)
  1. [Abstract] Notation for electric-field components (E^(t) and E^(n)) is introduced without explicit definition of the coordinate system relative to the sample surface and incidence plane.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive review and recommendation for major revision. We address each major comment below with our response and planned revisions to the manuscript.

read point-by-point responses

  1. Referee: [Abstract] Abstract and modeling discussion: the central claim that numerical E-field modeling 'corroborates the expected enhancement in the production of secondary electrons' and enables a 'new modality of SEM imaging' is unsupported by any experimental secondary-electron yield data, image contrast measurements, or polarization-dependent results; no test-sample images under 250 nm s-polarized illumination versus baseline are shown.

    Authors: We agree that the manuscript presents numerical E-field modeling to support the anticipated enhancement of secondary electron production but does not include experimental secondary-electron yield data, contrast measurements, or comparative images. The scope of this work is the development of the deep-UV co-illumination instrument with external controls and polarization tuning, together with modeling of the tangential and normal field components. We will revise the abstract and modeling discussion sections to explicitly state that the enhancement is predicted by the numerical results and that experimental validation of imaging contrast and yield improvements constitutes planned future work. This revision will ensure the claims accurately reflect the presented content without overstating current experimental evidence. revision: partial

  2. Referee: [Instrument description] The manuscript asserts that external mechanical control of UV-C LED position and tilt 'is achieved' at a 'robust and practical instrument level' without compromising SEM performance, yet provides no vacuum-integrity tests, imaging-resolution comparisons, or interference data to substantiate this load-bearing assumption for the proposed modality.

    Authors: The instrument description is based on the implemented external mechanical system for LED positioning, tilt, and polarization control. We acknowledge that explicit supporting data on vacuum integrity, SEM resolution comparisons before and after integration, and potential interference effects are not included. We will add a dedicated subsection or supplementary information describing the vacuum compatibility verification, any resolution and image quality checks performed during integration, and observations regarding interference with the SEM electron optics. These additions will provide the requested substantiation for the robustness claim. revision: yes

Circularity Check

0 steps flagged

No circularity: experimental instrument paper with independent numerical modeling

full rationale

The paper is a description of an experimental UV-SEM setup with external mechanical controls and a linear polarizer, plus standard numerical E-field modeling to illustrate expected secondary-electron enhancement. No derivation chain, fitted parameters renamed as predictions, or self-citation load-bearing steps exist. The modeling is presented as corroborative illustration rather than a self-referential prediction; no equations reduce to inputs by construction. This matches the default non-circular case for instrument-development work.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

This is an experimental instrument development paper. No free parameters, axioms, or invented entities are introduced in the abstract.

pith-pipeline@v0.9.0 · 5515 in / 1119 out tokens · 63699 ms · 2026-05-10T18:31:33.537301+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

27 extracted references · 27 canonical work pages

  1. [1]

    Gervinskas , author G

    author author G. Gervinskas , author G. Seniutinas ,\ and\ author S. Juodkazis ,\ title title Control of surface charge for high-fidelity nanostructuring of materials , \ https://doi.org/https://doi.org/10.1002/lpor.201300093 journal journal Laser & Photonics Reviews \ volume 7 ,\ pages 1049--1053 ( year 2013 ) ,\ https://arxiv.org/abs/https://onlinelibra...

    work page doi:10.1002/lpor.201300093 2013

  2. [2]

    Seniutinas , author A

    author author G. Seniutinas , author A. Balčytis ,\ and\ author S. Juodkazis ,\ title title Ultraviolet-photoelectric effect for augmented contrast and resolution in electron microscopy , \ https://doi.org/10.1063/1.4945357 journal journal APL Photonics \ volume 1 ,\ pages 021301 ( year 2016 ) ,\ https://arxiv.org/abs/https://pubs.aip.org/aip/app/article-...

    work page doi:10.1063/1.4945357 2016

  3. [3]

    author author L. S. \ Ikhsan , author Y. Masuda , author M. Kretkowski , author W. Inami ,\ and\ author Y. Kawata ,\ title title Contrast enhancement of sem image using photoelectric effect under UV LED irradiation , \ https://doi.org/10.3390/app152413250 journal journal Applied Sciences \ volume 15 ( year 2025 ),\ 10.3390/app152413250 NoStop

    work page doi:10.3390/app152413250 2025

  4. [4]

    author author G. D. \ Danilatos ,\ title title An atmospheric scanning electron microscope (ASEM) , \ https://doi.org/https://doi.org/10.1002/sca.4950030314 journal journal Scanning \ volume 3 ,\ pages 215--217 ( year 1980 ) ,\ https://arxiv.org/abs/https://onlinelibrary.wiley.com/doi/pdf/10.1002/sca.4950030314 https://onlinelibrary.wiley.com/doi/pdf/10.1...

    work page doi:10.1002/sca.4950030314 1980

  5. [5]

    Teramoto , author H

    author author K. Teramoto , author H. Nishiyama , author Y. Maruyama , author Y. Konyuuba , author Y. Abe , author D. Guarrera , author M. Suga ,\ and\ author C. Sato ,\ title title Morphological characterization of bacteria using the atmospheric scanning electron microscope (asem) , \ https://doi.org/10.1017/S1431927610055625 journal journal Microscopy a...

    work page doi:10.1017/s1431927610055625 2010

  6. [6]

    Kleindiek , author M

    author author S. Kleindiek , author M. Dadras , author K. Schock , author A. Lieb ,\ and\ author G. Renka ,\ title Combining SEM with AFM for in situ correlative microscopy , \ in\ https://doi.org/https://doi.org/10.1002/9783527808465.EMC2016.5289 booktitle European Microscopy Congress 2016: Proceedings \ ( publisher John Wiley & Sons, Ltd ,\ year 2016 )\...

    work page doi:10.1002/9783527808465.emc2016.5289 2016

  7. [7]

    Kretkowski , author K

    author author M. Kretkowski , author K. Hosomi , author H. Futamata , author W. Inami ,\ and\ author Y. Kawata ,\ title title Fast sample switching mechanism for atmospheric scanning electron microscopy and electron beam irradiation systems of living cells , \ https://doi.org/10.12693/APhysPolA.146.382 journal journal Acta Physica Polonica A \ volume 146 ...

    work page doi:10.12693/aphyspola.146.382 2024

  8. [8]

    Kretkowski , author J

    author author M. Kretkowski , author J. Katai , author H. Futamata , author W. Inami ,\ and\ author Y. Kawata ,\ title title Vacuum gripper-based practical method of gentle deposition of living cells and its filter substrates onto sin films for electron beam irradiation experiments , \ in\ @noop booktitle Recent Advances in Technology Research and Educati...

    work page 2024

  9. [9]

    Guaita , author S

    author author M. Guaita , author S. C. \ Watters ,\ and\ author S. Loerch ,\ title title Recent advances and current trends in cryo-electron microscopy , \ https://doi.org/https://doi.org/10.1016/j.sbi.2022.102484 journal journal Current Opinion in Structural Biology \ volume 77 ,\ pages 102484 ( year 2022 ) NoStop

    work page doi:10.1016/j.sbi.2022.102484 2022

  10. [10]

    Liu , author Z

    author author B. Liu , author Z. Hu , author P. Ruterana , author E. J. \ Olivier , author L. Gu ,\ and\ author Y. Wang ,\ title title Recent research progress of 4d-stem from methodology to application in materials science , \ https://doi.org/https://doi.org/10.1016/j.mattod.2025.12.029 journal journal Materials Today \ volume 92 ,\ pages 906--924 ( year...

    work page doi:10.1016/j.mattod.2025.12.029 2025

  11. [11]

    Troyon , author D

    author author M. Troyon , author D. Pastré , author J. Pierre Jouart ,\ and\ author J. Louis Beaudoin ,\ title title Scanning near-field cathodoluminescence microscopy , \ https://doi.org/https://doi.org/10.1016/S0304-3991(98)00049-7 journal journal Ultramicroscopy \ volume 75 ,\ pages 15--21 ( year 1998 ) NoStop

    work page doi:10.1016/s0304-3991(98)00049-7 1998

  12. [12]

    Jirak , author P

    author author J. Jirak , author P. Čudek ,\ and\ author V. Nedela ,\ title title Scintillation secondary electron detector for esem and sem , \ https://doi.org/10.1017/S1431927612008185 journal journal Microscopy and Microanalysis \ volume 18 ,\ pages 1266--1267 ( year 2012 ) NoStop

    work page doi:10.1017/s1431927612008185 2012

  13. [13]

    Raptis , author E

    author author N. Raptis , author E. Pikasis ,\ and\ author D. Syvridis ,\ title title Power losses in diffuse ultraviolet optical communications channels , \ https://doi.org/10.1364/OL.41.004421 journal journal Opt. Lett. \ volume 41 ,\ pages 4421--4424 ( year 2016 ) NoStop

    work page doi:10.1364/ol.41.004421 2016

  14. [14]

    Kim , author H

    author author J. Kim , author H. Ha , author G. H. \ Gu , author S.-G. \ Heo , author Y. Kim , author G.-H. \ Jeong ,\ and\ author H. S. \ Kim ,\ title title Argon plasma–induced compressive residual stress for simultaneous strength–ductility enhancement in a cocrfemnni high-entropy alloy , \ https://doi.org/https://doi.org/10.1016/j.msea.2026.150062 jour...

    work page doi:10.1016/j.msea.2026.150062 2026

  15. [15]

    Sathiyamoorthi \ and\ author H

    author author P. Sathiyamoorthi \ and\ author H. S. \ Kim ,\ title title High-entropy alloys with heterogeneous microstructure: Processing and mechanical properties , \ https://doi.org/https://doi.org/10.1016/j.pmatsci.2020.100709 journal journal Progress in Materials Science \ volume 123 ,\ pages 100709 ( year 2022 ) ,\ note a Festschrift in Honor of Bri...

    work page doi:10.1016/j.pmatsci.2020.100709 2020

  16. [16]

    \ Jung , author Y

    author author S.-G. \ Jung , author Y. Han , author J. H. \ Kim , author R. Hidayati , author J.-S. \ Rhyee , author J. M. \ Lee , author W. N. \ Kang , author W. S. \ Choi , author H.-R. \ Jeon , author J. Suk ,\ and\ author T. Park ,\ title title High critical current density and high-tolerance superconductivity in high-entropy alloy thin films , \ @noo...

    work page 2022

  17. [17]

    Zhang , author J

    author author N. Zhang , author J. Xu , author Z. Feng , author Y. Sun , author J. Huang , author X. Zhao , author X. Yao , author S. Chen , author L. Lu ,\ and\ author S. Luo ,\ title title Shock compression and spallation damage of high-entropy alloy al0.1cocrfeni , \ @noop journal journal Journal of Materials Science & Technology \ volume 128 ,\ pages ...

    work page 2022

  18. [18]

    Takenaka , author Y

    author author M. Takenaka , author Y. Hashimoto , author T. Iwasa , author T. Taketsugu , author G. Seniutinas , author A. Balčytis , author S. Juodkazis ,\ and\ author Y. Nishijima ,\ title title First principles calculations toward understanding sers of 2,2'-bipyridyl adsorbed on Au, Ag, and Au–Ag nanoalloy , \ https://doi.org/https://doi.org/10.1002/jc...

    work page doi:10.1002/jcc.25603 2019

  19. [19]

    Hashimoto , author G

    author author Y. Hashimoto , author G. Seniutinas , author A. Balcytis , author S. Juodkazis ,\ and\ author Y. Nishijima ,\ title title Au-Ag-Cu nano-alloys: tailoring of permittivity , \ @noop journal journal Scientific Reports \ volume 6 ,\ pages 25010 ( year 2016 ) NoStop

    work page 2016

  20. [20]

    Nishijima , author T

    author author Y. Nishijima , author T. Sudo , author Y. Matsuo ,\ and\ author S. Juodkazis ,\ title title A noble metal high-entropy alloy for mid-infrared metasurfaces , \ https://doi.org/https://doi.org/10.1016/j.eng.2025.01.017 journal journal Engineering \ volume 49 ,\ pages 81--89 ( year 2025 ) NoStop

    work page doi:10.1016/j.eng.2025.01.017 2025

  21. [21]

    Grineviciute , author H.-H

    author author L. Grineviciute , author H.-H. \ Huang , author H. Mu , author J. Nikitina , author N. H. A. \ Le , author T. Katkus , author A. S. M. \ Ang ,\ and\ author S. Juodkazis ,\ title title Surface texturing and localized oxidation of tantalum nano-film by fs-laser , \ https://doi.org/https://doi.org/10.1016/j.optlastec.2026.115018 journal journal...

    work page doi:10.1016/j.optlastec.2026.115018 2026

  22. [22]

    Sims and Bayden R

    author author C. Gassner , author J. Vongsvivut , author M. Ryu , author S. H. \ Ng , author M. Toplak , author V. Anand , author P. Takkalkar , author M. L. \ Fac , author N. A. \ Sims , author B. R. \ Wood , author M. J. \ Tobin , author S. Juodkazis ,\ and\ author J. Morikawa ,\ title title Bridging spectroscopy and advanced molecular orientation analy...

    work page doi:10.1016/j.compbiomed.2025.110573 2025

  23. [23]

    Anisotropy

    author author M. Ryu , author H.-H. \ Huang , author J. Vongsvivut , author S. H. \ Ng , author I. Dumbrytė , author D. Narbutis , author M. Malinauskas , author S. Juodkazis ,\ and\ author J. Morikawa ,\ title title Anisotropy analysis of bamboo and tooth using 4-angle polarization micro-spectroscopy , \ https://doi.org/https://doi.org/10.1002/nano.70099...

    work page doi:10.1002/nano.70099 2025

  24. [24]

    + command, where the argument is the citation key mentioned above. +

    work page

  25. [26]

    + command with the same argument as the + #1 + command. +

    work page

  26. [27]

    F =|- E ;. ())mۆ磰 /Ƹq. |A̛7 _ 9 cĈ qo /> ! & d0 -ߖqA<o dބ-'h\68a’LKm'( (Oϑ1K W]uUl? vddd`ܸq17M?ĭފE I ߃ y|GŨ((CZw|sã? < Y xWՅ6 uh4 u] hooǁ 8

    + commands may be crafted by hand or, preferably, generated by Bib . REV 4.2 includes Bib \ style files +apsrev4-2.bst+, +apsrmp4-2.bst+ appropriate for Physical Review and Reviews of Modern Physics, respectively. Example references This sample file employs the + + command, which formats the .bbl file and specifies which bibliographic databases are to be ...

    work page doi:10.1029/2002jd002268 2000

  27. [28]

    The AIP styles for REV 4 include Bib \ style files +aipnum.bst+ and +aipauth.bst+, appropriate for numbered and author-year bibliographies, respectively

    + commands may be crafted by hand or, preferably, generated by using Bib . The AIP styles for REV 4 include Bib \ style files +aipnum.bst+ and +aipauth.bst+, appropriate for numbered and author-year bibliographies, respectively. REV 4 will automatically choose the style appropriate for the document's selected class options: the default is numerical, and y...

    work page