Refractive Index Lab Report

The refractive index of the RLHHB crystal was determined by Brewster's angle method. For this study, a He-Ne Laser of wavelength 632.8 nm was used as a source. The laser was made to fall on the crystal placed on a rotary stage. The transmitted light traveling through the crystal gets polarized when the crystal has zero reflection. The angle at which the crystal has zero reflection is called Brewster's angle or polarizing angle (θp). The measured value of polarizing angle for the sample is 52.3 degree. Using the formula µ=tan θp, the linear refractive index of the grown crystal was calculated to be 1.293. Hardness, yield strength and stiffness constant are some of the mechanical constants and these properties can be evaluated by Vickers hardness test. Transparent crystal free from

In addition to identifying the materials with non-centro symmetric crystal structure, it is also used as a screening technique to identify the materials with the capacity for phase matching. The SHG intensity from the material is measured as a function of particle size. The continuous increase of SHG intensity with the increase of particle size and remaining essentially constant at particle sizes greater than the coherence length confirms the phase matching the behavior of the material [37-39]. A Q-switched Nd: YAG laser beam of wavelength (λ=1064nm) was used with a pulse width of 8ns and the repetition rate of 10Hz. The second harmonic signal generated in the RLHHB crystal was confirmed from the emission of green radiation from the powdered sample. Hence the SHG efficiency of RLHHB crystal is 1.90 times that of the standard KDP. The measurements of SHG output at various particle size show increasing SHG intensities with increasing particle sizes (figure.10). From this measurement, it was observed that the grown crystal proved the phase matching