Nanoimprint & Wafer-Level Optics
Industry Notes
High-index and low-index UV resins and coatings for imprinted micro- and nano-optics. Formulated to your stamp, your substrate and your cure, on wafer, plate or roll.
Why index
Index is the design variable in imprinted optics
An imprinted lens, grating or pillar is only as good as the index contrast it works with. A higher resin index shortens focal lengths, widens the field of view of a waveguide and lets a diffractive structure do more in less height. A lower index next to it gives the contrast back as cladding, gap fill or anti-reflection. Most imprint lines qualify one resin and live with its index. Kriya works the other way round: tell us the index, the viscosity and the cure your process needs, and we formulate to that.
What we formulate for imprint lines
| Function in your stack | Chemistry | Refractive index | Imprinted or coated | Cure |
|---|---|---|---|---|
| Imprint resin, low to mid index | 100 % solids UV, solvent-free | 1.34 – 1.65 | Imprinted | UV |
| Imprint resin, high index | Solvent-based UV resist | 1.79 at 633 nm (published) | Imprinted | UV |
| High-index resin and coating | Solvent-based UV, same family | up to 1.95 | Coated layer; available for imprint evaluation | UV |
| Low-index cladding and gap fill | UV hybrid | 1.30 – 1.40 | Coated layer | UV |
| Ultra-low-index layer | Sol-gel with hollow silica | 1.21 at 80 °C cure; 1.16 at high-temperature cure | Coated layer | Thermal |
| Anti-reflection topcoat | Multi-layer | R < 0.15 % | Coated layer | UV or thermal |
Solvent-free (100 % solids) resins currently reach n 1.65; higher indices are in development. Above n 1.79 our solvent-based grades are supplied as coatings and for imprint evaluation on your line.
Fits your process
We do not ask you to change your line. We ask for your process window and formulate inside it.
What we ask you for
- Format: wafer (200 or 300 mm), plate-to-plate, roll-to-plate or roll-to-roll
- Application method: spin coating, slot die, gravure, screen printing or dispensing
- Target viscosity and layer or residual-layer thickness
- Stamp or working-stamp material
- Cure: lamp or LED wavelength, dose, inert or air
- Substrate and its temperature limit
- Target index and wavelength, transmission and haze limits
- Downstream steps the layer must survive: solder reflow, damp heat, thermal cycling, overcoating
Imprint trials run on your line or at your equipment supplier's demo lab. We adjust the formulation between runs.
Published result
Proven in print: an imprinted high-index resist on thin-film solar cells
In a peer-reviewed study, a Kriya high-index resist (n 1.79 at 633 nm) was UV nano-imprinted with a moth-eye texture on top of CIGS solar cells, using a PDMS replica in wafer-by-wafer UV NIL. Because its index sits close to that of the transparent front contact (AZO, n 1.91 at 633 nm), light is not lost at the interface between the two. Across three absorber thicknesses the cells delivered on average 7.2 % more short-circuit current and 6.0 % higher efficiency, in line with a 7.0 % drop in reflection.
Burghoorn et al., AIP Advances 4, 127154 (2014), doi:10.1063/1.4905456. Open access.
The same formulation know-how now goes into resins for waveguide gratings, wafer-level lenses and metalenses.
Where imprinted optics meet our materials
Wafer-level lenses and diffractive elements
Imprint resins with the index your lens design assumes, plus low-index and AR layers for the same stack.
AR/VR waveguide gratings
High-index resins and coatings to widen the field of view, low-index layers to keep light guided.
Metalenses and flat optics
Imprinted structures with high-index coated layers on top or underneath.
Photonic packaging and co-packaged optics
Low-index claddings and index-matched layers for polymer waveguides and optical interfaces.
Image sensors and microLED
Index-engineered layers for light extraction, light collection and index matching.
Light management in photovoltaics
Textured high-index layers that cut front-surface reflection.
Run the numbers before you ask for a sample
Our calculators are built on published physics. See each one in demo mode, then request access to use it with your own values.
- Demo
/tools/nil-fidelityNIL pattern-fidelity estimator - Demo
/tools/metalensMetalens phase-profile designer - Demo
/tools/waveguide-fovAR waveguide TIR / FOV calculator - Demo
/tools/rgb-waveguideRGB waveguide stack designer - Demo
/tools/effective-mediumEffective medium index calculator - Demo
/tools/lri-particleLow-RI hollow-particle index calculator - Demo
/tools/tmmTMM thin-film reflectance simulator - Demo
/tools/cure-shrinkageCure-shrinkage and residual-stress estimator - Demo
/tools/stoney-stressStoney film-stress calculator - Demo
/tools/cte-mismatchCTE mismatch and warpage estimator - Demo
/tools/wet-thicknessWet-to-dry thickness converter - Demo
/tools/pi-lamp-matchUV lamp / resin absorbance match
How a project runs
- 01
Intake
You fill in our project intake sheet: index, process, substrate, volumes.
- 02
Review
We check the substrate and process window and tell you what is feasible.
- 03
Formulate and sample
We formulate to your window and send samples for your line.
- 04
Quotation
Once the samples work, you receive a quotation for your product code.
Frequently asked
Which refractive indices can be imprinted?
Our solvent-free UV resins cover n 1.34 to 1.65, and a Kriya solvent-based high-index resist with n 1.79 has been nano-imprinted in peer-reviewed work. The same family is available up to n 1.95 for coating and for imprint evaluation, and low-index layers down to n 1.16 complete the stack.
Are the materials PFAS-free?
Yes. Every material on this page can be supplied PFAS-free, including the low-index grades.
Do you have standard grades I can order?
No. Each material is formulated to your substrate and process and gets its own product code. That is how we hit your viscosity, cure and index at the same time.
Can you run imprint trials for us?
We formulate and supply the material. Trials run on your line or at your equipment supplier’s demo lab, and we adjust the formulation between runs.
Do you supply photoresists or other front-end semiconductor chemistry?
No. We make optical layers: imprint resins, index-matching layers, claddings and anti-reflection coatings.
Where are the materials made?
In the Netherlands, under ISO 9001:2015. All products are REACH-compliant.
Working on an imprinted optical element?
Send us your index target and process window. We will tell you what we can formulate.