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Survey Exams - EE 4270 October 5, 2005 Survey Exam Answer...

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Unformatted text preview: EE 4270 October 5, 2005 Survey Exam Answer four of the five questions only, clearly indicating the question not to be graded. Print yourname above, and on the back of this booklet. {You may use, when/g ropriate: F = ma, R=K1MNA, . In C’ ,.\ r DOF=K2MNA2.£}@1IS1+1/sz=1/f,E= mc2, ’ n1sine1 = n2Sln92} ask l l 3-17 ,f-f’ / "L1 A 7 1), This telescope is used to photograph a basketball player about 30 meters away. a) How large is the image formed on the film? (Assume he's 2 meters tall.) b) Is it inverted? c) What is the function of the dotted lens? lS-(MA. G! d) Compute the focal length of all three lenses. K e» 2) The same telescope in question (1) is used to look at the basketball player. - . c o n - n . u . . o . u a) How much, if any, does the telescope need to be refocused? ) How far away does the basketball player appear to be? c) If the front lens is 5 cm in diameter, what is the NA of the final lens? ............. .. d) If the telescope is used to photograph a star, ,how large will the image be? («g (WA/l r91 f$ 3) In the figure at the right light is incident from the right and left hand sides of a 450 prism made from glass with an index of refraction n = 2. Sketch the path taken by both beams of light within the prism, and exiting the prism. a) At what angle does the left hand beam enter the _ I, prism? s .- ....(Q..../ /. b) At what angle does the left hand beam leave the prism? c) At what angle does the right hand beam enter the rism? . o p .ftfi ...t/ d) At what angle does the right hand beam leave the prism? 9 go 4) In one fab line, integrated circuits are projection printed at a wavelength of 248 nm with a lens of NA 0.74. They have minimum feature widths of 0.1 pm and are printed with a depth of focus of 0.3 pm. k7 »2Lt% a a) Find K1. T93“? : {9 3“!" W o .314 “A ..... .3: I. b) Find K2. 2:): 00\’3/* M 1V 2 p MW e) What resolution could be obtained with the same NA by upgrading to a wavelength of 193 nm, assuming the same K1 could be maintained? ' q q 3 (i y ‘0’? d) What would the depth of focus be under these conditions, assuming the same K2 could be maintained? e) Find a NA such that both the resolution and the depth of focus are improved. \ I .r'J/‘v \\ d) To what diameterw’ill the laser beam be focused if the lens is placed at the distance you found in part b? \‘\..x u . . . . . . . . . . . . n EE 4270 Survey Exam November 28, 2005 ‘ ( q Answer‘four of the five questions only, clearly indicating the question not to be graded. Print your name above, and on the back of this booklet. {You may use, when appropriate: F = g ma, R=K12t/NA, DOF=K2)t/NA2, a) = Column --------- -- kd/nwo, 1/s1+1/52= 1/f, E = m02, Seat ...... .... " n1sin61 = n2sin62} 1) Sketch an energy level diagram for a four level laser. Indicate the relative populations in the levels both before and after excitation. Show the metastable level and the lasing transition. Find angexpression for the wavelength at which lasing occurs. v 2) A laser beam is modulated by either an acousto—optic modulator or an electro-optic modulator. If the modulators (and the laser beam) are made half as wide, what are ,the effects (if any) on ‘ AO mod EO mod a) The rise time of the transmitted light. .... . .. ...... .. b) The electrical drive required for modulation; . . . . . . . . . . . .. J, c) The extinction ratios. 1 7: ....... .. 2. ....... .. l, d) The minimum size to which the laser beam can be focused. ?/. ...... .. Z. ...... .. ' _ l. f e) The maximum amount of light that can be transmitted. u . . u . . . It]? , l l 3) Design a fiber optic link between Baton Rouge and New Orleans (125 Km), based on the following specs: a) Fiber loss: 0.2 dB/Km ’~=-> ” 2“ 5M”- b) Maximum fiber length: 10 Km ‘l"5r2KM>< V?) 0) Maximum loss per splice: 0.5 dB ” 7r all, d) Maximum amplifier gain: 25 dB The signal starts out at full strength, and should be at full signal strength at the end of the fiber link, so the fiber optic guide should terminate with an amplifier. Specify how many amplifiers are required, where they may be located, and what minimum gains they should have. in?“ ‘4“ w New in... a,“ , 7 Melly”? 1314qu L '3Ab-l" q‘tbk 7" ‘(TNC £2 i - ' W 9‘4 OWHA + ( i ' P“?- atoz ‘. .1,7.,# W-r.--«—~—+%me—-— 4” —-"» w -‘ ‘- ""7"" 1?“: M T W-(Bdb+7.b2db)+ :3 51w. 4),]‘we—beams of monochromatic light are incident on the same surface. The int sity of . ‘ ' one beam is l m ,2 and of the other is 100 mW/cm.2 Find the maximumfleeifsity on +20 the surface, the minim intensity on the surface, and the ratio b een the maximum to the minimum intensities, ‘ w 5) a. The lattice constant, or space between crystal planes in some particular crystal is 0.5 nm. It is observed that when X—rays are incident at an angle of 30 degrees to the normal, they are diffracted with high efficiency a a complementary angle‘of 30 degrees. What is the wavelength of the X-rays? ”‘ \ d ALMB b. It is observed that a collimated beam of light is diffracted by an angle of 30 degrees when it is incident on a grating of period 1 micron. What is the wavelength of the light? ...
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Survey Exams - EE 4270 October 5, 2005 Survey Exam Answer...

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