This review asks how two-photon lithography can combine submicron 3D geometry with functional inorganic materials. It synthesizes published fabrication studies in which photosensitive precursors are printed and converted through pyrolysis, annealing, or sintering into glass, ceramics, metals, or carbon, connecting precursor chemistry and structural evolution to applications in optics, mechanics, electronics, and biointerfaces. The reported demonstrations come from the reviewed literature; future directions are proposed. Controlling shrinkage while increasing throughput and integrating compatib

The laser chooses the shape. Precursor chemistry and thermal treatment determine what it becomes.

This review brings together routes for making intricate 3D glass, ceramic, metal, and carbon structures—at scales where a strand can be narrower than a wavelength of light.

One shape. Four transformations.

Start with a 10 µm precursor. Choose a reported material route, then convert it. Watch how preserving the shape can still mean changing its size.

Glassy carbon

A light-written polymer scaffold becomes carbon through pyrolysis.

900 °C · vacuum

The selected report produced 200 nm carbon struts and a reported material strength of 3 GPa.

All three dimensions shrink equally around the center. Each route comes from a different reported precursor, rather than a single resin that makes every material.

The model assumes freely shrinking geometry. Substrate attachment can make shrinkage nonuniform, as shown in the titania photonic-crystal study discussed in the review.

Land on 10 µm.

Your converted structure must finish at 10 µm wide. How large should you print the precursor?

A geometric design exercise using the selected route’s reported endpoint shrinkage.

Choose a precursor size, then test your design.

A shape first. A material next.

Two-photon lithography uses tightly focused femtosecond laser pulses to address tiny regions inside a precursor. In the polymerization routes explored here, light writes a solid 3D scaffold before heat changes its chemistry.

Localize the reaction

Two-photon absorption is strongly concentrated near the focus. Moving that focus crosslinks a 3D network where the material responds to the light.

Two-photon reaction probability rises approximately with intensity squared.

Reveal the green body

Development removes uncured precursor. The remaining “green body” holds the written geometry: an organic–inorganic hybrid or a carbon-forming polymer.

The printable body is an intermediate material.

Transform the framework

Thermal treatment removes or rearranges organic components and densifies or reorganizes the remaining framework. The temperature and atmosphere depend on the precursor.

Sintering, reduction, or carbonization produce different outcomes.

What does “TPL” include?

Two-photon lithography is the umbrella. TPP polymerizes a precursor; TPR reduces metal ions; TPD decomposes a precursor. This review focuses on thermal-treatment-assisted fabrication and also discusses direct metal-writing routes that can form metal during exposure.

Small by design. Functional by nature.

Microscale architecture joins the properties of a material with the behavior of its geometry. Explore demonstrations gathered by the review.

An optical lens, at the end of a fiber.

Beyond a single tiny structure.

The review points toward parallel writing for higher throughput, compatible thermal cycles for combining materials, and lower-temperature routes for integration with sensitive chips.

These are proposed directions: a path from exquisite individual microstructures toward more complex, integrated devices.

The science behind the experience.

Recent Advances in Two‐Photon Lithography of 3D Inorganic Microstructures: Glass, Ceramics, Metals, and Carbon

Xiaojiang Liu, Yahui Li, Yiting Huang, Angxi Zhu, Xiaolu Sun, Xiaoxiang Gao, Jing Sun, and Zhongze Gu.

Small 22: e74770 (2026). doi: 10.1002/smll.74770 ↗

This is a review of published studies. The conversion lab draws on selected reported examples in §§2.1, 3.4, 4.1, and 5.1. Application examples come from §§6.1–6.4.

Paper © 2026 Wiley-VCH GmbH. All rights reserved. The graphical abstract is an AI-generated conceptual illustration inspired by Figures 1–2, with schematic scales and material alternatives. Interactive diagrams are original conceptual illustrations.

Zhang et al., Nature Nanotechnology 19, 1813–1820 (2024), doi: 10.1038/s41565-024-01780-5, discussed in review §6.2. Its supplementary §9 and Figure 9 inform the substrate-attachment assumption in the lab. The supplementary material is linked in the model details.