Abstract
Electric-field-induced absorption of a type IIa diamond has been measured at various resolutions over a wider spectral range (2300 to 2700 cm-1) than hitherto. A new feature has been observed at 2335 cm-1 close to the Raman-active but otherwise infrared-inactive band at 2339 cm-1. Higher-resolution (5 cm-1) measurements in the neighbourhood of the k approximately=0 overtone resulted in a band being observed at exactly twice the Raman frequency, namely 2664 cm-1. This frequency is compared with a previous field-induced infrared result at 2660 cm-1 measured at a resolution of 28 cm-1 and a Raman scattering result at 2667 cm-1 measured at a resolution of 8 cm-1. The anisotropy of the overtone band is also found to agree with theoretical predictions.