13. A Q-switched laser uses a cavity with a length of 1m and an output coupler mirror reflectivity of r = 0.9 and an end

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13 A Q Switched Laser Uses A Cavity With A Length Of 1m And An Output Coupler Mirror Reflectivity Of R 0 9 And An End 1 (63.62 KiB) Viewed 77 times

13. A Q-switched laser uses a cavity with a length of 1m and an output coupler mirror reflectivity of r = 0.9 and an end mirror with reflectivity r = 1. The gain medium is an 5cm long Nd:YAG crystal, which is pumped by a flashlamp (laser wavelength = 1064nm, beam diameter 2mm). a) Draw the optical configuration in the laser cavity that shows Q-switch operation, clearly labeling all optical components necessary in generating the pulsed output. Also show the polarization state of the beam before and after each component. b) For a quarter wave electro-optical q-switch for a 9mm (w) x9mm (h) x 25mm (1) LI:N.Os crystal where the phase retardation between the components is given by: T=(ns – n;) 210 For LiNbO3 in question 1: n = n. + a rzey Al and n= no- n Where h is the height and lis the length of the crystal. Also calculate the quarter wave voltage. c) Assuming the laser output has an average power of 1W and repetition rate 1kHz with a pulse duration of 10ns, what is the peak power? d) If the cavity loss time is 20ns, estimate how much power per pulse you can extract if your Q- switch is fast enough for a pulse duration of ins. e) Design a grating that can resolve the wavelength output of this laser with at least 10pm precision. Determine the grating period as well as the FSR and resolving power. (HINT: remember resolving power of a grating and use the beam diameter of the laser).