Sairon Prism Coupler (SPA-4000)

Sairon Prism Coupler SPA-4000

Sairon Prism Coupler has been supplied mainly with leading companies, research institutes, and universities in Asia including Korea, Japan, China, Taiwan, Singapore, Malaysia, etc. Now we have partnered with JY TECH in South Korea, which is the manufacturer of Sairon Prism Coupler. We are the exclusive seller of SPA-4000. This excellent technology is available to all our EU customers.

What is Prism Coupler?

Prism Coupler is a measurement system to examine thin film properties such as refractive index, thickness, dn/dT (temperature dependency of index), propagation loss, or birefringence. It utilizes the prism coupling method. In the prism coupling method, unlike ellipsometry, reflection from the backside of substrate is less likely influence a measurement result. This means that special attention is not needed to measure a layer of film even on the transparent substrate. In addition, it can analyze samples with higher index than an Abbe refractometer. Also, the prism coupling method is less influenced by surface or boundary conditions as it utilizes propagating waves inside the thin film. Prism Coupler can measure the dependence of refractive index on wavelength by changing a incident laser beam. In order for prism coupler to obtain refractive index and thickness of the film at the same time, it needs to find at least two modes. To do so, sample thickness generally has to be as long as laser wavelength, or more.

Introduction Video

Key features

  • Loss measurement of high quality film with low propagation waveguide loss (~0.05dB/cm)
  • High resolution measurement for both refractive index and thickness of thin film
  • High accuracy measurement of bulk or substrate materials
  • dn/dT (index VS temperature) measurement
  • Dual layer film measurement
  • Index profile for the film with graded index
  • No information requirement of lower layer for dual layer film
  • Unrelated film / Substrate combinations
Prism Coupler details


Basic configuration

  • 632.8 nm He-Ne Laser
  • GGG(n=1.965) prism & Holder (index :<1.8)
  • One controller and PC interface(RS-232)
  • Si-photodiode Detector
  • TE measurement
  • Analysis software (O/S : MS Windows)


  • TM Mode option for each wavelength
  • Ge-Detector for Infrared Laser
  • Rutile (n=2.865) prism for high index refraction (index:1.8~2.45)
  • Solid state Laser ,Laser Diode Module(405~1550 nm);user choice
  • Sample Rotation system (-90 ~ +90 degree)
  • Thermo optic coefficient measurement system (dn/dT)
  • Liquid measurement system
  • Propagation LOSS measurement system


Refractive Index

Measurement range

(GGG prism)

1.0 – 1.8

Measurement range

(Rutile prism)

1.8 – 2.45
Accuracy +/- 0.001
Resolution +/- 0.0005


Measurement range 0.4 – 20 um
Accuracy +/- 0.5 %
Resolution +/- 0.01 um


Bulk (index only)

Accuracy +/- 0.001
Resolution +/- 0.0001


Liquid (index only)

Accuracy +/- 0.001
Resolution +/- 0.0001


Thermo-Optic Coefficient

Temperature range Room temp ~ 150 ℃


Loss measurement

Measuring limitation below 0.05 dB/cm

Demo system & Sample test

Would you like to see our system and test your samples? A demonstration system is accessible at our partner’s site in Belgium. Additionally, we can offer sample testing service for free at JY-TECH in South Korea. Please don’t hesitate to reach out to us for further details.


Please click the link below to download a brochure in your language.

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