Optical Coating

Substrate General Specification

• Substrate : Silicon / Germanium / Sapphire / Glass etc.
• Diameter : ~8inch
• Thickness : 0.55±0.05mm

Durability TEST Method

• Humidity : MIL-C-48797A 4.5.3.2
• Moderate Abrasion : MIL-C-48497A 4.5.3.3
• Adhesion : MIL-C-48497A 4.5.3.1

Optical Coating Specification

CWL(Center Wavelength Length, λ₀)

: Where λ₁ and λ₂ are the wavelength at 50% of band pass filter peak transmittance

FWHM(Full Width at Half Maximum)

: Band width of band pass filter

T_peak (Peak Transmittance)

: Maximum transmittance with in the band pass filter

Out of Band Blocking

: It is the amount of energy to the total energy out side the band pass.
Commonly refer to as signal to noise ratio or it is usually express in optical density(OD)

Band Pass Shape

: Band pass shape is defined to the number of cavities in a filter. The more cavity The number of cavities is defined by customer’s requirement about CWL, FWHM, Transmittance, and blocking.

Wavelength shift with angle

: Thin film interference filters change with incident angle. The following equation may be used to define the wavelength at a certain angle of incident.

Wavelength shift with Temperature

: The center wavelength will shift to a longer wavelength with increasing temperature.

T_avg (Average Transmittance)

: Transmittance average from λ₁ to λ₂ 50%

λc (Cut on or Cut off Wavelength)

: This is the wavelength at which the edge filter begin(or end) to transmit.

S_% (Slope of Filter in Percent)