Question

What is reproduced from a master holographic grating by moulding its grooves onto a resin surface or silica substrate?

(a) Diffraction grating

(b) Replica grating

(c) Silicate glasses

(d) Fused silica

The question was asked in an interview.

The origin of the question is Methods of Monitoring Foetal Heart Rate topic in division Foetal Monitoring Instruments of Biomedical Instrumentation

Answer 1

Right answer is (b) Replica grating

To explain: Holographic gratings used in commercial spectrophotometers are either original master gratings produced directly by an interferometer or are replica gratings. Replica gratings are reproduced from a master holographic grating by moulding its grooves onto a resin surface on a glass or silica substrate.