Temperature bandwidth of second-harmonic-generation in GdCOB crystal

Area of Science:

• Materials Science
• Optics and Photonics
• Crystallography

Background:

• Nonlinear optical (NLO) crystals are crucial for frequency conversion applications in lasers and photonics.
• Optimizing phase-matching conditions, such as temperature bandwidth, is essential for efficient NLO processes.
• Gadolinium calcium oxyborate (GdCa$_{4}$O(BO$_{3}$)$_{3}$ or GdCOB) is a promising NLO material.

Purpose of the Study:

• To investigate the temperature bandwidth of the second harmonic generation (SHG) phase-matching process in GdCOB crystals.
• To compare the temperature bandwidth of GdCOB with other established NLO crystals.
• To determine the optimal phase-matching angles for maximum temperature bandwidth in GdCOB.

Main Methods:

• Theoretical calculations were performed to predict phase-matching properties.
• Second harmonic generation (SHG) experiments were conducted to validate theoretical predictions.
• Temperature-dependent measurements were used to determine the phase-matching temperature bandwidth.

Main Results:

• GdCOB demonstrated a significantly broader temperature bandwidth compared to many conventional NLO crystals.
• The maximum temperature bandwidth for SHG was observed at specific angles (θ=135°, ϕ=47.3°) for a fundamental wavelength of 1,064 nm.
• Experimental results aligned with theoretical predictions.

Conclusions:

• GdCOB is a highly suitable material for nonlinear optical frequency conversion, especially under demanding temperature conditions.
• The broad temperature bandwidth of GdCOB enhances its utility in applications requiring stable and efficient frequency conversion.
• Further research can explore GdCOB in various high-power and extreme-environment optical systems.