Use this URL to cite or link to this record in EThOS:
Title: The non-linear optical properties of crystals and molecules
Author: Jeggo, C. R.
ISNI:       0000 0001 3589 8496
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 1971
Availability of Full Text:
Access from EThOS:
Full text unavailable from EThOS. Please try the link below.
Access from Institution:
We consider some of the factors which affect the magnitudes of the tensor coefficients describing the nonlinear optical effects of second-harmonic generation and the Pockels or linear electro-optic effect. The effects of molecular geometry are our particular concern. The electro-optic coefficients of double sulphates with the langbeinite structure are compared with those of tetragonal phosphates and arsenates by ascribing the nonlinearitiee to the XO4 tetrahedra. The unfavourable orientation of the SO4 groups is shown to be responsible for the low electro-optic coefficients of the langbeinites. These ideas are carried a stage further by assigning the nonlinearities to individual bonds. By this means the signs and magnitudes of the second-harmonic generation coefficients of several niobates are predicted from those of lithium niobate. Similar calculations are carried out for iodates, and empirical nonlinear optical bond polarisabilities are evaluated for a number of complex materials containing covalently bonded oxygen atoms. It is shown that the nonlinear polarisability depends on the electronegativity difference between the atoms forming the bond, and on their coordination. A further chapter uses the well-known anharmonic oscillator model to establish a connection between nonlinear optical effects and optical activity in crystals of sodium chlorate and sodium bromate.
Supervisor: Robinson, F. N. H. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available