e894a3g - 4 For a GaAs laser diode the laser emission area...

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ENSC 460/894 Assignment 3: (Oct. 21 due Oct. 28 2003) 1 The total power emitted by a CW laser in the TEM 00 mode is 10 W. If the focused spot 1/e 2 radius is 0.2 mm calculate the irradiance (power density) at the spot centre. (2 marks) 2. The beam radius (1/e 2 ) for a HeNe laser (running the most common line) TEM 00 mode is 0.5 mm. Determine the spot size at distances of 1 and 500 m from the waist.(8 marks) 3. If the spot radius for a HeNe TEM 00 mode beam entering a f=12.5 cm is 1.5 cm 3(a) Calculate the focused spot size.(3 marks) 3(b) Calculate the depth of focus to keep the spot size within 10% of the minimum value.(4 marks)
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Unformatted text preview: 4 For a GaAs laser diode the laser emission area is 1 micron thick by 50 microns wide. Calculate the divergence angle in the vertical an horizontal direction. What is the Rayleigh range for each direction, (8 marks) 5 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)...
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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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