Development Of Filter For Creating The Standard Spectral Coverage Used In Photorejuvenation

Recent significant developments in Photorejuvenation technology has created a demand for improvement of a key component, namely the filter. This paper describes the preparation of the filter in the device whose function is to produce the standard spectrum used in that device. TiO2 and SiO2 were chosen as high and low index materials and quartz as the substrate. Design of the stack was done by formula and needle optimizing was used to eliminate ripple. An average transmittance less than 0.3% in the 200 to 500(630) nm band and>95% in the band 570(650) to 1200nm was achieved by depositing films by ion assisted electron beam evaporation. An improved monitoring method was used to both decrease thickness errors and reduce loss in the TiO2. Observed wavelength shifts were analyzed and reasonable methods proposed to eliminate them. Examples of filters satisfying the requirements were prepared. These satisfy not only the optical requirements but also durability ones of adhesion, and water solubility.