Transmission Measurements in KTP and Isomorphic Compounds

Area of Science:

• Crystallography
• Optical Materials Science
• Nonlinear Optics

Background:

• Potassium titanyl phosphate (KTP) crystals exhibit optical biaxial properties.
• Anisotropic transmission in KTP crystals depends on light polarization relative to crystal axes.
• This property is critical for wavelength-conversion and quasi-phase-matching techniques.

Purpose of the Study:

• To measure and analyze the polarized transmission spectra of KTP family crystals.
• To investigate variations in spectral transmission and OH(-) absorption.
• To assess the impact of electric field poling on crystal transmission.

Main Methods:

• Polarized transmission spectra were measured using spectrophotometry and Fourier-transform infrared spectroscopy.
• Wavelength range studied: 0.3–6 µm.
• Transmission was measured before and after periodic electric field poling for select samples.

Main Results:

• Detailed polarized transmission spectra were obtained for KTP, RbTiOPO(4), RbTiOAsO(4) (RTA), and KTiOAsO(4).
• Variations in transmission at short/long wavelengths, visible light, and OH(-) absorption were characterized.
• Electric field poling showed no significant impact on the transmission of KTP and RTA samples.

Conclusions:

• Accurate knowledge of polarization-dependent transmission is essential for KTP-based optical applications.
• The study provides valuable data for selecting and utilizing KTP family materials in nonlinear optics.
• Understanding spectral variations and absorption is key for optimizing device performance.