e894a2k

# e894a2k - ENSC 460/894 Assignment 2: (Feb. 5 `09 due Feb....

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ENSC 460/894 Assignment 2: (Feb. 5 ‘09 due Feb. 12 ‘09) 1 (a) An atom has 1.5 eV separating two energy states. Calculate the ratio of the number of atoms in the excited state to the number in the ground state at T = 300, 700 and 1000 K. (7 marks) 1(b) What are the wavelengths and frequency of the light radiated in the transition from that excited state to the ground. (3 marks) 2 Assume a single layer antireflection coating is to be deposited on long IR ZnSe lens (n=2.4) for a wavelength of a CO 2 laser (10.4 microns). (a) What is the minimum thickness for this coating (3 marks) (b) What is the next smallest thickness that will give an AR coating. (2 marks) 3 If the round trip gain in a 30 cm long laser is 1%, what is the net gain coefficient ( g - α ). (5 marks) 4 For a ND:Yag laser calculate the ratio of the spontaneous radiation coefficient to the stimulated coefficient (Nd:YAG wavelength is 1064 nm). (5 marks) 5 A Huygens eyepiece (occular) is a combination of two positive thin lenses of the same glass. If the lenses are
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## This note was uploaded on 11/22/2010 for the course ENSC 470 taught by Professor Chapmann during the Spring '10 term at Simon Fraser.

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