Optical Properties of Material - Light Matter Interaction - Final Exam | OSE 5312, Exams of Chemistry

Download Optical Properties of Material - Light Matter Interaction - Final Exam | OSE 5312 and more Exams Chemistry in PDF only on Docsity! OSE 5312 Optical Properties of Materials Summer 2002 Final Exam Wednesday, July 24, 2002 15:00– 18:00 Part A of this exam is closed book, closed notes, while part B is a open notes, open book. You must therefore submit your answers to part A before you can look at any of your notes. Answer all questions. Try to use drawings & figures to help explain your answers. Clearly state all your assumptions, definitions and approximations. Begin each question on a new page. Write on one side of each page only! PART A – CLOSED BOOK, CLOSED NOTES 1. Give very brief definitions of the following terms: susceptibility, refractive index, population inversion, phase mismatch, inhomogeneous broadening. (10 points) 2. (a) What property must molecules have so that they display optical activity? In what direction must the induced magnetic dipole moment of such a molecule point when irradiated with linearly polarized light, and how does it affect the electric polarization? (b) Describe clearly how Faraday rotation may be used to create an "optical isolator" - a device that blocks light that is reflected back along its path. (10 points) 3. In figures 3(a)-(e) you will see plots of n() and () for a number of materials (for one, only ()is shown). The materials are given below. Identify which graph corresponds to which material, giving ample explanation for your choices. Your explanations can include reasons why you made each match and also (where appropriate) why you think each graph does not correspond to the other materials. This question will be graded based on your reasoning, more than on the accuracy of your matches. (i) Diamond (cubic crystalline carbon - solid), (ii) Cu (solid), (iii) SiO2 (Glass - solid), (iv) HCl (gas), (v) GaAs (solid), (10 points) 4. Sketches labeled graphs that approximately show the absorption coefficient versus frequency (from d.c. to ultraviolet) for the following gases. Your labels should indicate the mechanism associated with each absorption feature. Clearly show where zero is on your absorption coefficient axis. CO2, CO, H2 (10 points) PART B: OPEN BOOK, OPEN NOTES. (You must hand in your answers to part A before opening your books & notes.) 5. In a second harmonic generation experiment, it is found that a cw laser beam at  = 1.064 nm with peak power of 10 W can produce a second harmonic power of 10 W in a 1 mm thick KDP crystal. If the laser is then Q-switched, producing a peak power of 10 kW, what should the peak power of the second harmonic be? (15 points) 6. Locate the beam waist in the following cavity and find the far field diffraction angle of the output beam if the cavity is used for a laser with wavelength 633 nm. (15 points) 7. Estimate the ratio of the frequencies of the infrared absorption band for NaCl and KCl. State your assumptions. (A periodic table of the elements is attached.) (10 points) Question 8 on next page… d =1 m R 1 = 3 m R2 = 2 m Figures for question 3 io 10? io! 10 100 WAVELENGTH (um) Figure 3 (a) 10° pid ob et  10? (um) Jo! 10° WAVELENGTH 10 Figure 3 (b)  essao TTL ye TA. — 4 6 4 3 qe _% . 4 s me a Sena —4 iy =e y 4 z =F % pel atl alee glut tha 2 8 % & & 6 gum) WAVELENGTH Figure 3 (c)