Ellipsoidal mirrors have two conjugate foci. Light from one focus passes through the other after reflection. Ellipsoids collect a much higher fraction of total emitted light than a spherical mirror or conventional lens system. Thus, they are efficient over a much broader spectral range and exhibit no chromatic aberrations. Therefore, they are less expensive than many IR lens materials. These products can either be on-axis or off-axis, and can be supplied in a variety of materials; including BK7 glass, copper, fused silica, UV grade fused silica, nickel, and optical crown glass. Common coatings for ellipsoidal mirrors include none (uncoated), enhanced aluminum, protected aluminum, dielectric, protected gold, and silver. We can provide both on-axis and off-axis ellipsoidal mirrors, and specialize in production of medium to large-size custom ellipsoids with exacting tolerances, high grade surface finish and difficult coatings. Surface accuracy can be verified by the Foucault test or on the Zygo interferometer upon request. Please send us your specification or drawing and we will be happy to return a quotation ASAP. Our average response time is within 24 hours. Our optical designers are always available to assist with your special needs, and our factory in China is ready to meet your quantity requirements. Specifications: 1) Diameter: Φ25.4 - 1000mm 2) Material: BK7 (K9), or as requested 3) Surface quality: up to 10-5 S&D, or as requested 4) Surface accuracy: up to λ/20, or as requested 5) Clear aperture: >90% 6) Diameter tolerance: +(0.1 - 2)/-0.0mm (depends on the dimension) 7) Focal length tolerance: ±(1 - 1.5%) (depends on the dimension) 8) Edge thickness tolerance: +0/-10%, or as requested 9) Bevel: (0.1 - 2mm) x 45° (depends on the dimension) 10) Coating: as requested