Laser Physics ILaser Physics I PH481/581-3A (Mirov)( )

Control of Laser OscillatorsControl of Laser Oscillators

Lectures 16-18 chapter 7

Fall 2011C. Davis, “Lasers and Electro-optics”

1

Control of Laser Oscillation

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Single Longitudinal Mode Operation

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Mode-locking of lasers

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Mode-Locking

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Methods of mode-locking

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Active mode-locking

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Passive Mode-Locking

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Mode-locking operation of a pulsed Nd:YAG laser with LiF:F2- color center crystal as simultaneous saturable absorber and active laser media

Mirov, APL1992

22Mode lock train duration – 80 ns; Pulse duration in the train 500 fs

Advanced mode-locked laser system

23to overlap or collide as they pass through an intracavity saturable absorber (dye).

Colliding pulse mode-locking

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Pulse compression

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Optimum coupling

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1. A laser (=10.6 m, =3x10-25 m2, =4 s) measured to have an intensity of 0.3 W/cm2 emerging from one end of the laser, which has two identical mirrors each with a transmission of 10%. The gain of the laser is also measured to be 0.5. What is the optimum output mirror transmission?

34 1026.6 10 3 101 1 6 /hv

24 25

0

6.6 10 3 101. 1.56 /10.6 10 3 10 4(1 ) (1-A-0.9)2. ( ln ) 0.3=1.56 (0.5 ln 0.9)

2 2 1 1 0 9

s

out s

hvI W cm

I I A R L RR

2

2 2 1 1-0.96.82 10

3 1; 0 116 11 6%opt o

RAT L T A L A

3. 1; 0.116 11.6%opt oT A L AA A

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