16-01-2013, 03:52 PM
Kdp crystal
Kdp crystal.pptx (Size: 2.68 MB / Downloads: 46)
Nlo test – Kurtz powder shg method
The test was performed by illuminating the powder sample with fundamental mode of a Nd: YAG laser
The produced Second Harmonic signal is compared with the SHG efficiency of KDP crystal
In the case of UTMC the Second Harmonic efficiency is 2.6 times that of KDP
In the case of BMTS and UMTS the SHG efficiency is 1.5 and 2.8 times respectively.
DIELECTRIC STUDIES
Dielectric measurement is one of the useful characterizations of electrical response of solids.
A study of the dielectric properties of solids gives information about the electric field distribution within the solid.
The frequency dependence of these properties gives a great insight into the material’s applications.
The different polarization mechanisms in solids can be understood from the study of dielectric constant as a function of frequency and temperature.
Dielectric studies of urea thiourea doped crystals
The dielectric measurements of the crystals were carried out by using K-band microwave test bench
Frequency range of K- band microwave test bench is 18-26.6 GHz
Crystals were shaped to the wave guide dimensions
Four orientations of each crystal were measured
The standing wave patterns of the crystals were observed by mw detector, CRO and multimeter
Graph drawn between distance (x-axis) and detector voltage (y-axis)
The shift ‘Δ’ was found between the successive minimums of with and without sample
ROLE OF MICROWAVE TEST BENCH
Microwave test bench equipped with Gunn oscillator used to generate microwaves
Rectangular wave guide is employed with TE10 mode
K-band - wider dimension is 1.1 cm and 0.4 cm as breadth
DIELECTRIC CONSTANT Vs NLO PROPERTY
MILLER RULE : lower value of dielectric constant enhances Second Harmonic Generation (SHG) coefficient
Semi organic crystals exhibit good NLO property
Non Linear Optical property plays a major role in photonic devices fabrications