Nature of the infrared spectrum in band-edge region of KTiOPO4

Abstract

The infrared transmission spectra of KTiOPO4 (KTP) have been closely inspected in the region between 4000 and 1000 cm−1 (2.5–10 μm) using single-crystal samples of various thicknesses. The spectral information obtained reveals that the band edge at 4.5 μm is due to the first overtone of the ν3 tetrahedral phosphate fundamental vibration. A heretofore questionable absorption centered at 3.3 μm has been shown to be the second overtone of this same fundamental vibration.

Yb:Ta:RbTiOPO4, A New Strategy to Further Increase the Lanthanide Concentration in Crystals of the KTiOPO4 Family

“…At 6300 nm, the combination band (ν 3 + ν 4 ) appears, and at 7500 nm, the band that closes the optical transparency window in the IR region, which corresponds to the combination band (ν 1 + ν 2 ), appears. The obtained spectrum is close to that previously obtained by Jacco et al 2 for KTP, and the bands' assignments have been done with the help of previously published studies. 2,27 In the spectra of the RbTi 0.95 Ta 0.03 Yb 0.02 OPO 4 crystal, the band between 900 and 990 nm corresponds to the Yb 3+ absorption band associated with the 2 F 7/2 f 2 F 5/2 transition of Yb 3+ , which will be studied in more depth in the next section.…”

“…The spectrum obtained (see Figure 5), shows four peaks in the low-temperature spectra, and five peaks in the room-temperature spectra, corresponding to the emission from the excited state 2 F 5/2 to the 2 F 7/2 ground state. The most intense peak is centered at 972.2 nm, and it determines the energy of the 2 F 5/2 (0′) sublevel because this peak corresponds to the 2 Both absorption and emission spectra obtained for Yb: Ta:RTP crystals match well, in shape and in position of the peaks with the spectra previously obtained for Yb:Nb:RTP crystals, 28 showing only a slight blue-shift of the peaks in Yb:Ta:RTP crystals. This is important because a broad laser emission around 1 µm can also be obtained in these crystals that may allow for the generation of ultrashort laser pulses and the development of new tunable laser sources.…”

“…KTiOPO 4 (KTP) and its isostructural RbTiOPO 4 (RTP) are well-known for their high nonlinear optical coefficients. Particularly KTP has been used as a frequency doubler of lasers emitting in the IR spectral range, , but this application can be extended as well to RTP.…”

Enhanced stimulated Raman scattering in optical parametric oscillators from periodically poled KTiOPO4

“…Notably, the enhanced SRS is observed only in the OPOs where the wavelength of the generated idler falls within the midinfrared absorption band starting at around 3.3 m in KTP and associated with the second overtone of the 3 fundamental vibration of the phosphate ion. 7 Moreover, the SRS Stokes and anti-Stokes replicas in all cases were generated from the resonated signal wave, while the pump and idler waves were not affected by SRS. It should be noted that the Stokes lines are far removed from the QPM bandwidth in PPKTP so the cross seeding of the Raman-like features in the idler region by the parametric interaction is very inefficient.…”

Crystallization Region, Crystal Growth, and Characterization of Rubidium Titanyl Phosphate Codoped with Niobium and Lanthanide Ions

“…KTiOPO 4 (KTP) crystals and some of its isostructural materials have good nonlinear optical properties, which make them attractive for use as frequency doublers for diode lasers in the IR region …”