Nonlinear Optical Spectroscopy of Ce³⁺ Ions in Insulating Crystals

Abstract

Coherent anti-Stokes Raman spe~troscopy (CARS) involving electronic states of rare earth ions in insulating crystals has shown only limited success, unlike CARS involving vibrational transitions. The major problem is that x< 3 >R, the contribution to the third order susceptibility from the electronic states of the rare earth ions, is often obscured by x< 3 >NR, the contribution from the b~lk crystal which can be orders of magnitude larger. 3.3 Selection Rules 3.4 Experimental Details 3.5 Results and Discussion 3.5.1 2Fsn (r6) ~ 5d (r7)3.5.2 2Fsn (r6) ~ 5d <r ~ 3.5.3 Summary Chapter Four Electronic Coherent Anti-Stokes Raman Spectroscopy in CeF3 4.1 The Resonant and the Nonresonant Susceptibility 4.1.1 The Resonant Susceptibility 4.1.2 The Nonresonant Susceptibility 4. 2 Experimental 4.3 • Analysis 4.4 Summary Appendix 4.1 Calculation of lx< 3 )Rimax and <Jzz A 4.1.1 A 4.1.2 A 4.1.3 A 4.1.4 Application of the Axe Theory of Two-photon Processes Calculating I( 4f I r 15d )I for Ce 3 + in CeF 3 Wavefunctions for Ce 3 + in CeF 3 Calculation of the Electronic Raman Cross Section Appendix 4.2 Stimulated Electronic Raman Gain A 4.2.1 A 4.2.2 A 4.2.3 References Sumner Davis has been my research director and optics teacher. Looking back, I am amazed that I have learned so much from one person. Most importantly, however, Sumner believed in me even when I did not. Wednesday group meetings were made truly memorable by the presence of Davis group members Mark Abrams, Sandalphon, Yan Wu, Phil Becker and Glen Williams. Glen and Phil laid the foundation for this dissertation by their exhaustive study of the linear electronic spectroscopy of rare earth phosphate crystals. As my office mate for two years, Glen instilled in me a fascination with cerium and nonstandard English. Norm Edelstein has been responsible for both financial and scientific support of this work. Norm is fond of saying "Pa 4 + is just like Ce 3 +." After our long collaboration, my response is now "OK Norm,'you may be right, but I'd rather work with cerium." Among the LBL staff, Jerry Bucher pretended to be a wet blanket, but he is not, while George Shalimoff had to endure my foolishness. Other current and former grad students and LBLers assisted me in numerous ways on many occasions -the Medhursts (Laura and Jane), giant-