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Unformatted text preview: EEV4270 Midterm Exam October 12 2005 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 = ma, s=K1N NA, E = mcz, DOF=K2M NA2, Column ......... ..
a) = )uZ/ﬂiwo, llS1+1 /52= f, n1sin61 = n28ln92, 1/f=(n—1)~(1/R1+1/R2)} Seat".61 ....... " ML 2 .r l _ y :_ . ’
i ) {MA I "ll" 0‘4» 1) This microscope is used to photograph a bug about 1 mm high. I l l _ .
a) How far is the objective lens from the slide? q ; "L 5’0 2 3/
b) What is the magniﬁcation of the objective? Ar ‘ Y 2‘0
c) Is the image on the ﬁlm inverted? i 0 A .... .. O” ' KL“ {5
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d) What is the focal length of the eyepiece? —?L g + ,l. .g i t t '7, g ' ‘l ‘ ‘ ‘——._
e) What is the size of the image on the ﬁlm? 9 "~ W a
on ,, x 22$. FM.”— 1 ' 20 0'4 W“ 49” 7.7
2) The same microcope in question (1) is used to look at the bug.
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a) What is the overall magmﬁcation? a; E— __ Ll ' ’0 "—10 ........ ‘) b) How large does the bug appear to be? (use 25 cm as normal viewing distance). l LeLce 222
c) What is the focal length of the ﬁeld lens? 70 2.: AK I .... ..: ...... .. 7 {2.105 d) If the objective is 5 mm in diameter, what is its NA? ‘ glam e) In visible light (A = 0.5pm) what is the smallest feature that can be seen?
'2 ~;‘ ' . . L ' “s s. . . .
3) You Wish to de51gn a lenﬁo image a luminous object on to a screen at a distance of 36 cm, so that its image is twice as large as the object. 'Z
May$5”! a) How far from the object will you place the lens? 1
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b) What IS the focal length of the lens. a (e 2%  6'05.
0) Choose radii for the lens, assuming the index of refraction n = 1.5.
K  2 (L. > ' p! Repeat, if the image is to be the same size as the object.
. Ls ,. l i d) How far% the object will you place the lens?
e) What is the focal length of the lens? J; 4 [1% , [111‘ f) Choose radii for the lens, assuming the index of refraction n = 1.5. are l (a; e. ‘7 1.9 sL. 30 tri.“(o'€‘3
IL, 9i 6, :3 rt; Sal92 4) In the figures at the right, both the 600 prism and
the lens have an index of refraction of 1.6. a) Light passes through prism parallel to the base.
Find the angle 6 at which it is incident to the prism. €31" b) The radius of curvature at the frontisurface of the
lens is 10 cm. Where do the two rays cross? (vi, 9 ~o 5AA} 54466" 0
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W") E VAN [MW " 'rected laser beams at CHIWHCS. Assume at the gaussian beam fr a C02 laser a a wavelength of 10.6
umh’as to be focused to a diameter of 1 meteryég: to damage th missile. Q) If the missile is ’lleglM damaged by e laserbeam. EE 4270 Endterm Exam December 5,2005 (15‘3" l 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. a\
Column..3.... Seat ............... .. You may request that any equation you
wish be written on the blackboard. xivl
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1) Sketch an energy level diagram for a three level laser. Indicate the relative populations I
in the levels both before and after excitation. Show the metastable level and the lasing “ 4
transition. Find an expression for the wavelength at which lasing occurs. 2 2) MC— atbgé’gjs 5'04"“;
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‘LABMJGA b(( .15 b H E7: (2 ( C;on 9 2) Indicate whether the following statements are true or false: T t.a)eThe resolution of a zone plate is approximately equal to the width of the last zone.
T Enb) The resolution of a zone plate depends on its numerical aperture. ‘
T In) The resolution of a zone plate is independent of the wavelength.
‘; '/.§;...d) The focal length of a zone plate is independent of the wavelength.
l: V glue) Doubling the diameter of a zone plate also doubles its focal length. XL: KN:
fl” 1/ The same zone plate cin‘ have both a real and a virtual focus. ’ $ g)»C/O§ lasers are used to produce the ﬁnest lines in integrated circuits. 5y Apt/{3Q
VT T L/ T i) The wavelength of some lasers can be continuously varied. .. ...h) Laser machining requires less power if the laser is pulsed. ? Q switching is used to minimize the rier on YAG lasers. .\ ' "‘"SQQHCheck whether the following properties apply to either acoustooptic modulators or elecnkptmdulators. W D > AO mod < EO mod / a) Requires polarized light. \ ' . . . . . . . ..
b) Shifts the wavelength of the modulated light. r ‘y c) Requires a high voltage supply for operation. . ........ .. d) Requires a radio frequency source for operation. ........ .. e) Can independently control more than one laser beam. . . . . . . . . . . . . . . . . . . .. x.__ _ 4) Design a ﬁber optic link between Baton Rouge and Orlando (1100 Km), based on the
following specs: a) Fiber loss: 0.1 dB/Km ‘ “0 “lg b) Maximum ﬁber length: 10 Km llO 640W  I a . 1 t f c) Maximum loss per splice: 0.25 dB \96 war; 7.3.73 ‘ ' d) Ampliﬁer gain: 5 to 25 dB e) Maximum number of ampliﬁers before regeneration: 5 4,755 3‘5 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 the
minimum number of ampliﬁers and regenerators required, where they may be locatedI ‘ y.
and what gains they should have. ~« L~W pg 00‘ + O "'2ﬁ2?_2¢,&73‘ A A A A A «an ‘iso': \Rmt [YOH Wok 200K
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Agave I; 290 W W ﬁ£.(§g.¢d"0~ .920qu
5) A portion of a wide coherent laser beam passes through a slit, producing a maximum
intensity of 1 mW/cm2 on a distant screen. What are the maximum intensity, and the avera e intensity, on the screen if there are r
g A 2A: 1?, I + mm. ‘
39 o I max I average ' 7 E '" a) 2 slits. W A: l
b) 3 slits! ...l.tt‘i’lésa:i€. ..“>..v~.~.w.lt+s.$ ' W “‘ ‘ .iwm t O “LL/«a
c) n slits. 1:: J3}? ! CAN; Z 9 d) If I max / I average is not a constant, explain why it is not. 0 (C (2/2 x 1+ t: a, Coms‘lc,tLL+’ hlmuae 1m 51 ~13“ “A I ‘ Imageo (fl“6 ‘1) Azﬁﬂ‘" l QQC/im & {mite : a. x Ila.1 ‘2’ 4‘\w€.me\’eCuv€ WC (ffl5 fut—qt Tﬁﬁﬂ") w
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This note was uploaded on 02/26/2012 for the course EE 2120 taught by Professor Aravena during the Fall '08 term at LSU.
 Fall '08
 ARAVENA

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