Microscopy and microRaman study of periodically poled domains in deeply thinned lithium niobate wafers

• Published in: Optical materials 2016-07, Vol.57 (C), p.243-248
• Main Authors: Bullen, P.S., Huang, H.-C., Yang, H., Dadap, J.I., Kymissis, I., Osgood, R.M.
• Format: Article
• Language: English
• Subjects: Deoxidizing; Domain broadening; Electric potential; Lithium niobates; Microscopy; Periodically poled lithium niobate (PPLN); Poling in thinned lithium niobate; Raman spectroscopy; Scanning; Spreading; Variability; Voltage
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2016.05.002

The domain structure of poled deeply thinned lithium niobate is investigated as a function of sample thickness. Free-standing samples of thickness from 25 to 500 μm are prepared by a multiple-cycle polish and annealing procedure and then periodically poled. Using these samples and employing micro-Raman scattering and scanning electron, atomic force, and optical microscopy together, the domain broadening and poling voltage are found to vary in a regular and significant manner. The poled domains show a reduction in width spreading of 38% as the sample thickness is reduced from 500 to 25 μm. Micro-Raman probe measurements verify the quality and the uniformity of the poled domains and provide insight into their thickness-dependent poling contrast. •Direct demonstration of forming PPLN in thinned samples.•Direct measurement of domain broadening vs thickness over a large thickness range from 25 μm to 500 μm.•Use of microRaman measurements over a range of sample thickness to show high spatial uniformity within the poled domains.•Analysis of thickness-dependent Raman intensity contrast between poled and unpoled domains.