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In the optical sytem sketched here, linearly polarized light from an oscillator goes through an “optical isolator”
consisting in a combination of polarizing cubes, a (45 deg) Faraday rotator, and a wave plate. The beam goes
through a series of optical systems (stretcher, regenerative amplifier) before being sent to the multipass amplifier.
These optical systems return the same polarization. Indicate by a sketch (xin the plane of the figure, y
orthogonal, and z along k) the state of polarization at each passage through a polarizing element. Explain why
(how) the beam can be made to follow the red arrows.
Regenerative Amplifier
Temporal
Compressor
Multipass Power Amplifier
Temporal
Stretcher
To Frequency
Tripler
l/2
From Ti:Sapphire
Oscillator
Optical Isolator
p-polarized
The regenerative amplifier.
The s-polarized beam (pulse train) comes from the isolator (arrives from the top of this figure), is deflected by a thin film
polarizer TFP. What is the voltage sequence to be applied to the Pockel’s cell PC such that at t<0 all pulses make a single
passage through the cavity before being extracted. At t=0 one pulse is trapped in the cavity until it makes 20 RT,
and is extracted at t = te
s-polarized
Express all voltages as fraction of the half wave voltage Vhw
TS
FM
p-polarized
Pump Beam
EM2
PM
TFP
PC=Pockel Cell; PM= Pump Mirror;
TFP=Thin Film Polarizer; FM= Folding Mirror;
TS= Ti:Sapphire Crystal; EM1= End Mirror (R=3m);
Em2= End Mirror (Flat)
PC
A pulse short compared with the dimensions of the Mach Zehnder interferometer is sent through this system,
split in two, reflected by the mirror M2. The “blue” pulse arrives between the two pulses created by the Mach
Zehnder and change the relative phase of these two pulses. Describe the outputs detected in A and B.
P is a polarizer.
TRIPLER -FS UV
AMPLIFIER
M2
l/2
LASER
M
A
P
E
B
METALLIC REFLECTOR (M) TO ADJUST THE PHASES
CCD
ETALON (E) TO BALANCE THE AMPLITUDES
Explain the path and polarization of the pulse circulating clockwise and counterclockwise in the ring and in
the tail of the ring.
How should be the axis of the quarter wave plates to have a p polarized pulse circulating in
both directions in this cavity?
Will a magnetic field (as indicated) have an effect on the cavity modes in either direction?
saturable
absorber
dye jet TGG
l
B field