Method for producing hologram by pico-second laser

Abstract

Disclosed is a method of producing a hologram through a two-beam laser interfering exposure process, which comprises emitting a coherent laser light with a pulse width (τ) ranging from greater than 900 femtoseconds to 100 picoseconds and a laser power of 10 μJ/pulse or more using a solid-state laser as a light source, dividing the pulses light from the laser into two beams, controlling the two beams temporally and spatially in such a manner that the two beam are converged on a surface of or inside a workpiece for recording a hologram while matching the respective converged spots of the two beams with one another temporally and spatially to create the interference therebetween so as to record a surface-relief hologram on the surface of the workpiece or an embedded hologram inside the workpiece in an irreversible manner. The present invention can solve a problem with a conventional process of recording a hologram in a non-photosensitive material in an irreversible manner using interfering femtosecond laser pulses, specifically, distortion in the waveforms of pulsed laser beams and resulting instability in recording of an embedded hologram due to a non-linear optical interaction between the femtosecond laser pulses and air/the material.