Holographic Encoding of Permanent Gratings Embedded in Diamond by Two Beam Interference of a Single Femtosecond Near-Infrared Laser Pulse

It is reported on the first demonstration that non-erasable gratings may be holographically encoded in diamonds by colliding a pair of pulses split from a single high peak power femtosecond laser pulse using a Ti: sapphire laser. Confocal microscopic observation revealed that gratings are formed beneath the top surface at ~0.5 to ~1.5 µm. Conversion of diamond into diamond-like or amorphous carbon occurs in the encoded portion, resulting in the refractive index modulation. The present method is applicable for encoding volume holograms for all crystalline and amorphous transparent dielectrics including sapphire, LiNbO3, SiC, ZnSe and various types of glass.