Transmission and damage-threshold measurements in AgGaSe(2) at 2.1 microm

Area of Science:

• Materials Science
• Optics
• Solid State Physics

Background:

• Silver gallium selenide (AgGaSe2) is a nonlinear optical crystal with applications in infrared technologies.
• Understanding its optical properties, particularly transmission loss and laser-induced damage, is crucial for device performance.

Purpose of the Study:

• To measure transmission loss coefficients in AgGaSe2 at 2.1 micrometers.
• To determine the primary factor influencing the laser damage threshold of AgGaSe2.
• To evaluate the damage threshold of coated AgGaSe2 surfaces and the impact of surface quality.

Main Methods:

• Transmission loss coefficients were measured for AgGaSe2 at a wavelength of 2.1 micrometers.
• Laser-induced damage experiments were conducted using nanosecond laser pulses.
• The influence of energy density versus peak-power density on damage was investigated.
• Coated AgGaSe2 samples with varying surface quality were subjected to damage threshold testing.

Main Results:

• Transmission loss coefficients ranged from 0.012 to 0.072 cm(-1).
• Energy density was identified as the critical parameter for AgGaSe2 damage threshold, not peak-power density.
• Initial coated-surface damage thresholds were 1.1-2.5 J/cm(2) with 180-nsec pulses.
• Improved surface quality led to significantly higher damage thresholds, averaging 3 J/cm(2) and reaching up to 3.5 J/cm(2).

Conclusions:

• AgGaSe2 exhibits moderate transmission losses at 2.1 micrometers.
• Laser damage in AgGaSe2 is primarily governed by energy density.
• Enhancing the surface quality of coated AgGaSe2 is essential for achieving high laser damage thresholds, critical for high-power optical applications.