EXPERIMENTS AND NUMERICAL SIMULATIONS ON BEAM BENDING AND TRANSVERSE BEAM ENCODING BY SPATIAL SELF-PHASE AND CROSS-PHASE MODULATION IN RUBY

Experiments and numerical simulations are Performed on the no near bea m evolution of simultaneously propagating cw argon-ion and HeNe laser beam through a ruby rod. The HeNe probe beam exhibits a deflection of nearly 12 mrad when a 1.5 W, 514.5 nm laser beam is injected into the ruby rod at an angle to the probe. The copropagating geometry is also studied where the azimuthally symmetric transverse beam encoding leads to complex ring structures in both the HeNe and argon-ion laser beams . The numerical simulations are compared with the experimental data to obtain the cross-phase modulation term. Using previously reported val ues for the saturable nonlinear index of ruby and a nonlinear index fo r cross-phase modulation n(c)= 1.35Re(n2), the nonlinear wave equation in two transverse dimensions is numerically solved to predict the ben ding angles and emerging beam profiles. These findings are discussed i n light of previous experiments in ruby as well as the possibility of using these effects for producing nanosecond optical switching systems .