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

Abstract

Transient and steady-state measurements of photo-induced birefringence variations in single domain and periodically poled lithium niobate (LN) crystals containing different non-photorefractive impurities are presented. The birefringence change is induced by a 532-nm laser beam in the intensity range 0-500 W/cm 2 , and is probed by 632.8-and 1523-nm beams. Data were taken at 25 and 50°C. We find that HfO 2 doping is very effective in reducing the photorefraction. This is interesting also because it is known that Hafnium-doped LN crystals can be periodically-poled during growth. The analysis of the rise and decay of the induced birefringence shows that doping considerably increases both the photoconductivity and the dark conductivity of the LN crystals.

Composition dependence of the electro‐optic properties of iron‐doped lithium niobate crystals mounted as bulk modulator

“…Numerous studies point that LN crystals present a large set of possibilities to control, that is, suppress or enhance the photorefractive effect for adaptation to opto‐electronic devices and applications. With a significant but nonexhaustive list of dopants, currently the most used dopants for functionalizing LN crystals via the electro‐optic effect, include divalent Mg 2+ , and Zn 2+ , trivalent In 3+ , Er 3+ , and Sc 3+ , and tetravalent Zr 4+ , Sc 4+ , and Hf 4+ ,. Moreover, in the fields of optical information processing, holographic volume storage, phase conjugation or interferometric holography, iron‐doped LN crystals present the fascinating possibilities, thanks to their high photorefractive sensitivity.…”