Fiber Laser for ERL

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Fiber Laser for ERL

• Zach Ulibarri
• Mentor Zhi Zhao

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Introduction

• Goal
• Mode locked laser oscillator
• 50 MHz repetition rate
• Designed for emittance measurement

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Laser Basics

• Population inversion in gain medium

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Laser Basics

• Stimulated photon emission

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Laser Basics

• Light emits and repeats process

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Mode Locked Lasers

• Saturable absorber

Transmission
Intensity
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Mode Locked Lasers

• With saturable absorber in place, random noise
  can create pulses

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Mode Locked Lasers

• How do we add sufficient noise to the cavity?

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Mode Locked Lasers

• How do we add sufficient noise to the cavity?

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Artificial Saturable Absorber

• Wave plates create phase shift induced intensity
  modulation

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Experimental Setup
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Top View
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Mode Locked Lasers
19.8ns
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Mode Locked Lasers

• Detector is too slow

FWHM suggests Pulse width 1.22 ns
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Autocorrelator Measurement

• Michelson interferometer creates small delay
• Aligned pulses create second harmonic generation

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Intensity Autocorrelation
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Intensity Autocorrelation
FWHM suggests pulse width 8ps. Very large!
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Chirp

• Index of refraction depends on wavelength
• Compensate with diffraction grating

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Chirp
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Intensity Autocorrelation
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Dechirped Autocorrelation
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Dechirped Autocorrelation
FWHM 330 fs 1.5220
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Interferometric Autocorrelation
FWHM suggests pulse width 220fs
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Spectrum
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Simulated Results
Agrees with estimates
200fs
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Pulse Energy

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Peak Power
Chirped
Dechirped

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Questions?