Uncoated Suprasil ® 311 plates,
wedge < 0.2 arcsec
Fabry-Perot etalons are extremely narrow line width filters with a series of sharp transmission peaks, separated by the free spectral range (FSR).
FSR depends on the optical thickness of the etalons only, whereas the finesse (F) is determined not only by the reflectivity of the coatings, but mainly on surface quality, parallelism, homogeneity of the substrate material and defect free coatings.
Solid etalons can be tuned by tilting and by temperature change. If a minimum resolvable resolution is needed, the reflectivity finesse FR can be calculated with
With the diagrams the reflectivity R of the layers can be determined.The final finesse of the etalon is limited in most cases by the flatness finesse FF (flatness of /20 gives FF = 20) for beam diameter 20 mm. With thinner beams FF can grow to > 200.
Pairs of etalons in series may be used to obtain ultra high resolution combined with a very long FSR. The resulting finesse of such a combination can be one oder of magnitude higher.
Besides lower costs solid etalons offer the following advantages over air spaced etalons for intra cavity use:
lower size harder coatings with
higher damage thresholds.
|Diameter||Thickness||Wedge /||Flatness||Surface||Suprasil 311||FSR|
|Article-No.||€||nm @ 633nm||GHz|
|All components with an price are available from stock.|