Nonlinear Optical Properties of Some Newly Developed Crystals for Measurement of Ultrafast Laser Pulses

Second harmonic generation (SHG) in nonlinear optical crystal is well-established technique for the measurement of the pulse-width of ultrafast femtosecond laser pulses. However, only selected nonlinear crystalline materials are suited for this purpose due to the limitations in transparency cut-off, limited phase-matching wavelength range, and large difference between the group velocities of the fundamental and harmonic waves. It is found that some newly discovered crystals, such as CsLiB6O10 (CLBO), K2Al2B2O7 (KABO), Li2B4O7 (LB4), and KBe2BO3F (KBBF) have some advantageous characteristics for use in ultrafast nonlinear optical applications. Here we have presented several linear and nonlinear optical parameters including phase-matching angle, angular and spectral acceptance bandwidths, walk-off angle, nonlinear coupling coefficient, and group-velocity mismatch for generation of second harmonic of ultrafast laser radiations by employing type-I and type-II SHG techniques in these crystals.