Wavelength tunable narrow band filter

An image sensor, comprising:

• a first photodetector and a second photodetector in a substrate;
• and
• a filter overlying the first and second photodetectors and comprising:
• a first distributed Bragg reflector (DBR) and a second DBR overlying the first DBR;
• an interlayer between the first and second DBRs;
• and
• a first columnar structure and a second columnar structure that are inset into the interlayer and that are respectively and directly over the first and second photodetectors,
• wherein a thickness of the interlayer has a first thickness value overlying the first photodetector and further has a second thickness value greater than the first thickness value overlying the second photodetector, and wherein the second columnar structure has a height greater than the first thickness value.

An image sensor, comprising:

• a first photodetector, a second photodetector, and a third photodetector in a substrate;
• a first distributed Bragg reflector (DBR) overlying the first, second, and third photodetectors;
• a second DBR overlying the first DBR;
• a first interlayer between the first and second DBRs;
• and
• a second interlayer inset into the first interlayer and having a different refractive index than the first interlayer,
• wherein a first ratio of the second interlayer to the first interlayer throughout a first area covering the first photodetector is different than a second ratio of the second interlayer to the first interlayer throughout a second area covering the second photodetector, wherein the second interlayer has a first thickness value overlying the first photodetector, wherein the first interlayer has the first thickness value overlying the second photodetector, and wherein the first and second interlayers respectively have a second thickness value and a third thickness value that overlie the third photodetector and that are less than the first thickness value.