Analysis on the electric field distribution in a relaxor ferroelectric KTN crystal near field-induced phase transition using optical deflection measurements.

Spatially analyzing non-uniform distributions of electric phenomena such as electric field and permittivity in ferroelectric devices is very challenging. In this study, we apply an optical beam deflection method to map the non-uniform electric phenomena in relaxor ferroelectric potassium tantalate niobate (KTN) crystals. To adequately correlate the physical parameters and their spatial distributions in KTN crystals, a general model that describes the giant electro-optic response and associated beam deflection is derived.

Single chip super broadband InGaN/GaN LED enabled by nanostructured substrate.

A new type of LED, single chip super broadband InGaN/GaN LED is presented in this paper. The LED is composed of an InGaN/GaN quantum well layer deposited on the nanostructured sapphire substrate, inscribed by femtosecond laser ablation. The super broadband emission is enabled due to the large variation of indium composition in a small local area so that different wavelengths can be emitted over a small area and the summation of these different emission wavelengths forms super broadband emission, which covers the entire visible spectral range.

Broadband supercontinuum generation covering UV to mid-IR region by using three pumping sources in single crystal sapphire fiber.

In this paper, we demonstrate that the the bandwidth of the supercontinuum spectrum generated in a large mode area sapphire fiber can be enhanced by employing triple pumping sources. Three pumping sources with wavelengths of 784 nm, 1290 nm, and 2000 nm are launched into a single crystal sapphire fiber that is 5 cm in length and has a core diameter of 115 microm. The nonlinear interactions due to self-phase modulation and four-wave mixing form a broadband supercontinuum that covers the UV, visible, near-IR and lower mid-IR regions.

Broadband IR supercontinuum generation using single crystal sapphire fibers.

In this paper, an investigation on broadband IR supercontinuum generation in single crystal sapphire fibers is presented. It is experimentally demonstrated that broadband IR supercontinuum spectrum (up to 3.2microm) can be achieved by launching ultra-short femtosecond laser pulses into single crystal sapphire fiber with a dimension 115microm in diameter and 5cm in length, which covers both the near IR spectral region and the lower end of the mid-IR spectral range.