Frequency and wavelength dependences of electro-optic coefficients in inorganic crystals

Abstract

The frequency dependence of electro-optic coefficients in congruent and stoichiometric LiNbO 3 ,L i T a O 3 , β-BaB 2 O 4 and KTiOPO 4 was determined and compared to each other for the first time in a wide frequency range from DC up to 150 MHz. The measurements have been investigated as a function of laser wavelength from 0.5 to 1.3 µm. Clamped and unclamped electro-optic coefficients as well as the acoustic contribution have been established for each crystal.

High-photorefractive resistance of hafnium-doped, single-domain, and periodically-poled lithium niobate crystals

“…We note that the observed photorefractivity reduction cannot be explained by invoking the wavelengthdispersion of the parameter R eff , since the changes of the refractive indices are fractionally small when going from λ 1 to λ 2 , and the measured electro-optical coefficients of lithium niobate have a rather weak dispersion over the same wavelength range [23]. Noting that the two measurements are performed in different ranges of green-beam intensities, the reduction could be due to a decrease of the sensitivity δS when the green-beam intensity is increased.…”

High-repetition-rate picosecond pump laser based on an Yb:YAG disk amplifier for optical parametric amplification

“…BBO Q-switches have been reported to exhibit negligible piezoelectric ringing at repetition rates of up to 6 kHz. Only a small acoustic contribution around 5 % to the total electro-optic coefficient has been measured [98] explaining why no piezoelectric ringing is detected with BBO Pockels cells up to 6 kHz [99]. The combination of high optical damage threshold, (single-shot bulk damage threshold value, up to 50 GW/cm 2 at 1064 nm [100]) reduced piezoelectric ringing and relatively low insertion loss makes this crystal particularly attractive for electro-optic Q-switching of high peak and average power solid-state lasers [96].…”

Oxide crystals for electro-optic Q-switching of lasers

“…Recently Abarkan et al [7] experimentally showed that the coefficients r T and r S for a number of crystals can differ substantially. This is especially true for lithium niobate (LNB) and lithium tantalate (LTA).…”

“…This difference is determined by the acoustic contribution in the intermediate frequency range in which the optical signal oscillates with a period that is governed by the main piezoelectric-resonance frequencies. The accompanying "piezoelectric ringing" limits the use of many crystals as Q-switches at high repetition rates, because the amplitude r a = r Tr S is directly related to the strength of the acoustic resonance [7]. Moreover, rather small coefficients r S can lead to undesirably high driving voltages when the cavity in Pockels cells is rapidly turned on and off.…”

“…When the repetition rates of electric pulses are of the order of several kilohertz, the inverse piezoelectric effect suppresses the acoustic ringing only at frequencies above 10 MHz and the constantstrain coefficients for the LNB and LTA compounds are equal to 3.8 and 1.0 pm/V respectively [7]. In practice, a substantial piezoelectric ringing in LNB Q-switches has already been observed at a repetition rate of 1 kHz [14].…”