Lenses are a transparent optical component consisting of one or more pieces of optical glass with surfaces so curved (usually spherical) that they serve to converge or diverge the transmitted rays from an object, thus forming a real or virtual image of that object. Lenses are classified as single lenses, cylindrical lenses and achromatic lenses. COT provides these lenses with BK7 and fused silica and other optical glasses. Special focusing systems can be designed by COT’s engineers upon request.