Optical limiting threshold in carbon suspensions and reverse saturable absorber materials

Area of Science:

• Materials Science
• Optics
• Nonlinear Optics

Background:

• Optical limiting materials are crucial for protecting sensitive optical components and sensors from high-energy laser pulses.
• Carbon black suspensions are investigated for their potential as effective optical limiters due to their nonlinear optical properties.

Purpose of the Study:

• To measure and report the threshold energy fluence for optical limiting using nanosecond and microsecond pulses in a specific carbon suspension, Defence Research Establishment Valcartier carbon black suspension (CBS)-100.
• To establish a figure of merit for comparing the optical limiting performance of different carbon suspensions.

Main Methods:

• Utilized an f/20 optical system with a small analysis aperture for precise measurement of threshold energy fluence.
• Validated the measurement technique using known reverse saturable absorber materials and other carbon suspensions documented in the literature.

Main Results:

• Achieved low threshold energy fluences: 24 mJ/cm² for nanosecond pulses and 100 mJ/cm² for microsecond pulses.
• Developed a factor of merit to rank the optical limiting performance of various carbon suspensions.
• CBS-100 exhibited the best optical limiting performance among the tested suspensions for both short and long pulses.

Conclusions:

• Defence Research Establishment Valcartier carbon black suspension (CBS)-100 is a highly effective material for optical limiting applications.
• The developed factor of merit provides a reliable method for evaluating and comparing optical limiting materials.
• CBS-100 presents a promising solution for laser protection across different pulse durations.