ENSC 470 Problem Workshop 6 & 7 Dec. 12/13, 2016

6 (a) In an electro-optic Pockels cell calculate the refractive index change per cm in Lithium Niobate (LiNbO3) for an applied field of 100 V/cm (use note values for parameters). Note n=2.272 for LiNbO3 . (b) How long must a longitudinal Pockels cell be to cause a phase change of 90o between the fast and slow rays for a ruby laser (λ = 694.3 nm). Assume the cell is at 45o to the laser polarization to begin with.

7. It is required to drill 0.3 mm diameter holes in a nickel sheet using a pulsed Nd:YAG 2nd harmonic laser with a 9 kW peak power output. How long will it take to reach the melting point on the top surface? (b) To reach the boiling point at the surface so hole drilling can begin? k = 90 W/m K, C = 420 J/kg K, α = 2.28x10-5 m2/s, R = 0.65 ρ = 8900 Kg/m3, Lv = 6.47x106 J/kg, Tm = 1700 K, Tv = 3110 K 

 

(b)

8. The system geometries used to record transmission and reflection holograms are illustrated in the figure below. The reference beam UR is collimated and object beam U0 originates from a point source. By using the hologram equations in the notes and drawing sketches, describe the results when the transmission and reflection holograms are constructed with: (a) UP = UR (b) UP = UR* (c) UP = UO (d) UP = UO*

Solution