Ultrashort pulse-generation by saturable absorber mirrors based on polymer-embedded carbon nanotubes

Area of Science:

• Optics and Photonics
• Materials Science
• Laser Physics

Background:

• Passive mode locking is crucial for generating ultrashort laser pulses.
• Traditional saturable absorbers often require complex fabrication methods like epitaxial growth.
• Carbon nanotubes (CNTs) offer unique optical properties suitable for saturable absorption.

Purpose of the Study:

• To demonstrate a novel method for fabricating saturable absorbers using carbon nanotubes (CNTs).
• To investigate the performance of CNT-based saturable absorbers in passive mode locking of solid-state lasers.
• To achieve ultrafast pulse generation with short recovery times.

Main Methods:

• Fabrication of saturable absorbers by spin-coating a polymer doped with CNTs onto dielectric laser-mirrors.
• Integration of CNT saturable absorber mirrors into Nd:glass and Er/Yb:glass laser cavities.
• Characterization of generated laser pulses, including pulse duration and wavelength.

Main Results:

• Successful demonstration of passive mode locking using CNT-based saturable absorbers.
• Achieved broadband artificial saturable absorber mirrors with ultrafast recovery times.
• Generated the shortest pulse to date (68 fs) in a self-starting Er/Yb:bulk-glass laser configuration at 1570 nm.
• Reported a pulse repetition rate of 85 MHz.

Conclusions:

• CNT-based saturable absorbers provide an effective and simpler alternative to traditional methods.
• The spin-coating technique allows for versatile fabrication on various substrates.
• This approach enables efficient generation of ultrashort laser pulses for diverse applications.