A method for forming an optical component includes (i) depositing optical layers on a base, and (ii) controlling a thickness of a tuning layer by (a) depositing the tuning layer on the optical layers, (b) measuring a first optical characteristic, (c) measuring a second optical characteristic after continued deposition of the tuning layer, (d) determining whether the second optical characteristic has decreased compared to the first optical characteristic, (e) when the second optical characteristic has not decreased, continuing deposition of the tuning layer and returning to steps (ii)(b)-(e), when the second optical characteristic has decreased, terminating the depositing and removing a portion of the tuning layer formed during a period of time defined from when an increase/decrease of the second optical characteristic is stopped to when the second optical characteristic is changed to be decreased, and (f) adding a layer of a lower refractive index on the tuning layer.