Patent ID: 7330256

Claim:
A system for characterizing optical properties of a sample, the system comprising: a light source for generating a broadband optical beam; a first mirror positioned to image the light source on the sample; and a second mirror positioned to collect light reflected by a measurement area of the sample, wherein an angle of incidence of light directed to the sample is θ 1 , where 0°≦θ 1 ≦3.5°, and wherein (i) the first mirror is shaped such that at least 9.5% of a conical light beam is not reflected by the first mirror, (ii) the second mirror is shaped such that at least 9.5% of a conical light beam is not reflected by the second mirror, (iii) the first mirror is shaped and positioned such that at least 9.5% of a cross sectional area of a light beam is not reflected by the first mirror, (iv) the second mirror is shaped and positioned such that at least 9.5% of a cross sectional area of a light beam is not reflected by the second mirror.