US 11,796,887 B2
Capacitively controlled fabry-perot interferometer
Heikki Saari, Vtt (FI); Martti Blomberg, Vtt (FI); and Sari Elomaa, Vtt (FI)
Assigned to TEKNOLOGIAN TUTKIMUSKESKUS VTT OY, Espoo (FI)
Filed by TEKNOLOGIAN TUTKIMUSKESKUS VTT OY, Espoo (FI)
Filed on Sep. 14, 2021, as Appl. No. 17/474,781.
Claims priority of application No. 20205917 (FI), filed on Sep. 22, 2020.
Prior Publication US 2022/0091471 A1, Mar. 24, 2022
Int. Cl. G02F 1/21 (2006.01); G01J 3/26 (2006.01)
CPC G02F 1/213 (2021.01) [G01J 3/26 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A capacitively controlled Fabry-Perot interferometer, said interferometer comprising:
a first mirror layer which comprises a first metallic thin-film layer embedded in a first insulating layer, wherein the first metallic thin-film layer is configured as a first reflector in the first mirror layer, and the first metallic thin-film layer comprises a central region, and a control region;
a second mirror layer which comprises a second metallic thin-film layer embedded in a second insulating layer, wherein the second metallic thin-film layer is configured as a second reflector in the second mirror layer, and the second metallic thin-film layer comprises a central region and a control region, and the central region of the first metallic thin-film layer is at least partly aligned in an actuation direction with the central region of the second metallic thin-film layer, and the control region of the first metallic thin-film layer is at least partly aligned in the actuation direction with the control region of the second metallic thin-film layer;
a first control electrode and a first dielectric layer, wherein the first dielectric layer lies between the first control electrode and at least a part of the control region of the first metallic thin-film layer, wherein the interferometer comprises a first control capacitor disposed between the first control electrode and the first metallic thin-film layer, wherein the first dielectric layer is a part of the first insulating layer in which the first metallic thin-film layer is embedded, and wherein the first control electrode is on top of and is in contact with the first mirror layer; and
a second control electrode which is electrically coupled to the control region of the second metallic thin-film layer, wherein the second mirror layer lies on a substrate, and the first mirror layer is suspended above the substrate by two spacers so that a tuning cavity is defined between the first and the second mirror layers,
wherein the interferometer further comprises a second dielectric layer, wherein the second dielectric layer lies between the second control electrode and at least a part of a control region of the second metallic thin-film layer, wherein the interferometer further comprises a second control capacitor disposed between the second control electrode and the second metallic thin-film layer, wherein one of the spacers also lies between the second control electrode and the second metallic thin-film layer, and wherein the second control electrode is on top of and is in contact with the first mirror layer.