Rocky Mountain Instrument Co.
1.303.664.5000
 

Optical Components:

Developed in conjunction with Ext-Joom.com

Dichroic Filters » Visible / Near IR

Dichroic Filter coatings are designed to transmit one spectral region (passband) and reflect another (rejection band).

The filter is a Short Wave Pass (SWP) if the passband is to the left of the transition slope, and a Long Wave Pass (LWP) if the passband is to the right of the slope.

The advantages of dichroic filters over colored glass filters are:
  1. The rejection band is reflected rather than absorbed.
  2. Steeper transition slope between the passband and the rejection band; i.e. sharper cut-on or cut-off.
  3. Coatings can be custom designed for specific center wavelengths. 
 
 

sketch-visible-near-ir

RMI Standard Specifications
Angle of Incidence: 0º or 45º
Passband: T = 50% + 5% at λ0
Tavg > 90% at 0º 
Tavg > 85% at 45º
Rejection Band: Ravg > 99% at 0º 
Ravg > 98% at 45º
Damage Threshold:  3 J/cm2, 10 ns pulse