---
_id: '13495'
abstract:
- lang: eng
  text: The use of additive manufacturing for rapid prototyping of near-infrared and
    terahertz components provides seamless and error-free production. This article
    discusses the additive manufacturing and post-processing of axicons and their
    performance evaluation using attenuation and near-field-measurements based fundamental
    techniques. The axicons are manufactured using the materials cyclic olefin copolymer
    (TOPAS) and polymethyl methacrylate (PMMA), for their respective use in terahertz
    and near-infrared applications. The optical and terahertz components manufactured
    using traditional 3D-printing processes, e.g., fused filament fabrication or stereolithography
    apparatus exhibit high surface roughness in the range of 15 ± 2.5 µm, resulting
    in undesired propagation and scattering in the near infrared wavelengths. This
    research work proposes an economical post-processing technique for additively
    manufactured terahertz and near-infrared axicons for applications in multispectral
    characterization, e.g., bio-sensing. The authors used an enhanced method of dip-coating,
    which involves interval dipping and intermittent hardening to achieve better surface
    finish. An emphasis is placed on interval dipping and intermittent hardening,
    which lead to excellent transparency in case of additively-manufactured near-infrared
    axicons. The dip-coated samples exhibit surface roughness below 10 nm. With the
    use of heated resin material as the coating layer, due to reduced viscosity, the
    resin material distributes uniformly over the surface of the 3D-printed terahertz
    and near-infrared axicons. The authors also observed that the DOF length deviation
    between unprocessed and enhanced dip-coated axicons remains within the measurement
    error estimation from analytical calculations. In addition to the improved surface
    finish and transparency, the coatings are also closely matched in refractive index
    to the axicon material. Such post-processed axicons pave the way for producing
    a wide array of systems in the fields of communication, imaging, and bio-sensing.
article_number: '264'
author:
- first_name: Abhijeet Narendra
  full_name: Shrotri, Abhijeet Narendra
  id: '74090'
  last_name: Shrotri
  orcid: 0000-0003-2116-156X
- first_name: Annamarija
  full_name: Starsaja, Annamarija
  last_name: Starsaja
- first_name: Suraj
  full_name: Joshi, Suraj
  last_name: Joshi
- first_name: Sascha
  full_name: Preu, Sascha
  last_name: Preu
- first_name: Oliver
  full_name: Stübbe, Oliver
  id: '51864'
  last_name: Stübbe
  orcid: 0000-0001-7293-6893
citation:
  ama: Shrotri AN, Starsaja A, Joshi S, Preu S, Stübbe O. Multispectral Characterization
    of Additively Manufactured and Dip-Coated Axicons. <i>Photonics</i>. 2026;13(3).
    doi:<a href="https://doi.org/10.3390/photonics13030264">10.3390/photonics13030264</a>
  apa: Shrotri, A. N., Starsaja, A., Joshi, S., Preu, S., &#38; Stübbe, O. (2026).
    Multispectral Characterization of Additively Manufactured and Dip-Coated Axicons.
    <i>Photonics</i>, <i>13</i>(3), Article 264. <a href="https://doi.org/10.3390/photonics13030264">https://doi.org/10.3390/photonics13030264</a>
  bjps: <b>Shrotri AN <i>et al.</i></b> (2026) Multispectral Characterization of Additively
    Manufactured and Dip-Coated Axicons. <i>Photonics</i> <b>13</b>.
  chicago: Shrotri, Abhijeet Narendra, Annamarija Starsaja, Suraj Joshi, Sascha Preu,
    and Oliver Stübbe. “Multispectral Characterization of Additively Manufactured
    and Dip-Coated Axicons.” <i>Photonics</i> 13, no. 3 (2026). <a href="https://doi.org/10.3390/photonics13030264">https://doi.org/10.3390/photonics13030264</a>.
  chicago-de: Shrotri, Abhijeet Narendra, Annamarija Starsaja, Suraj Joshi, Sascha
    Preu und Oliver Stübbe. 2026. Multispectral Characterization of Additively Manufactured
    and Dip-Coated Axicons. <i>Photonics</i> 13, Nr. 3. doi:<a href="https://doi.org/10.3390/photonics13030264">10.3390/photonics13030264</a>,
    .
  din1505-2-1: '<span style="font-variant:small-caps;">Shrotri, Abhijeet Narendra</span>
    ; <span style="font-variant:small-caps;">Starsaja, Annamarija</span> ; <span style="font-variant:small-caps;">Joshi,
    Suraj</span> ; <span style="font-variant:small-caps;">Preu, Sascha</span> ; <span
    style="font-variant:small-caps;">Stübbe, Oliver</span>: Multispectral Characterization
    of Additively Manufactured and Dip-Coated Axicons. In: <i>Photonics</i> Bd. 13.
    Basel, MDPI AG (2026), Nr. 3'
  havard: A.N. Shrotri, A. Starsaja, S. Joshi, S. Preu, O. Stübbe, Multispectral Characterization
    of Additively Manufactured and Dip-Coated Axicons, Photonics. 13 (2026).
  ieee: 'A. N. Shrotri, A. Starsaja, S. Joshi, S. Preu, and O. Stübbe, “Multispectral
    Characterization of Additively Manufactured and Dip-Coated Axicons,” <i>Photonics</i>,
    vol. 13, no. 3, Art. no. 264, 2026, doi: <a href="https://doi.org/10.3390/photonics13030264">10.3390/photonics13030264</a>.'
  mla: Shrotri, Abhijeet Narendra, et al. “Multispectral Characterization of Additively
    Manufactured and Dip-Coated Axicons.” <i>Photonics</i>, vol. 13, no. 3, 264, 2026,
    <a href="https://doi.org/10.3390/photonics13030264">https://doi.org/10.3390/photonics13030264</a>.
  short: A.N. Shrotri, A. Starsaja, S. Joshi, S. Preu, O. Stübbe, Photonics 13 (2026).
  ufg: '<b>Shrotri, Abhijeet Narendra u. a.</b>: Multispectral Characterization of
    Additively Manufactured and Dip-Coated Axicons, in: <i>Photonics</i> 13 (2026),
    H. 3.'
  van: Shrotri AN, Starsaja A, Joshi S, Preu S, Stübbe O. Multispectral Characterization
    of Additively Manufactured and Dip-Coated Axicons. Photonics. 2026;13(3).
date_created: 2026-03-12T07:07:54Z
date_updated: 2026-03-12T07:12:29Z
department:
- _id: DEP5020
- _id: DEP6020
doi: 10.3390/photonics13030264
intvolume: '        13'
issue: '3'
keyword:
- additive manufacturing
- stereolithography
- dip-coating
- post-processing
language:
- iso: eng
place: Basel
publication: Photonics
publication_identifier:
  issn:
  - 2304-6732
publication_status: published
publisher: MDPI AG
status: public
title: Multispectral Characterization of Additively Manufactured and Dip-Coated Axicons
type: scientific_journal_article
user_id: '83781'
volume: 13
year: '2026'
...