Determination of Optimum Laser Beam Expansion Ratio for Nd: YAG Harmonics for Different Ranges

Abstract

Beam expander plays a key role in laser devices for remote detection for transmission unit. The study is conducted for Nd: YAG laser, λ =1064 nm and its harmonics, namely the second harmonic generation, λ = 532 nm, the third harmonic generation, λ = 355 nm, and the fourth harmonic generation, λ = 266 nm. Determination of expansion ratio of beam expander for specific wavelength and detection range is the key in beam expander optical design for determining minimum possible laser spot size at the target. Knowing optimum expansion ratio implies to reduce laser transmitting unit dimensions and increase performance efficiency of receiving unit.