Temperature-dependent Sellmeier Equation Research Articles

Temperature-tunable nanosecond optical parametric oscillator based on periodically poled [formula omitted

We report a compact quasi-phase-matched optical parametric oscillator (OPO) using periodically poled MgO-doped LiNbO 3 with different grating periods. The OPO is pumped by a diode-pumped passively Q-switched Nd:YAG laser providing 4.8-ns pulses at 5.4-kHz repetition rate. The OPO generates signal and idler wavelengths tunable in the ranges of 1.5– 1.7 μ m and 2.8– 3.6 μ m , respectively, by changing the crystal temperature between room temperature and 170 ∘ C . The temperature-dependent Sellmeier equation for the extraordinary refractive index of MgO-doped LiNbO 3 is modified in the Mid-IR region, which gives an accurate prediction of the experimental temperature-tuning results. The linewidth of the signal wave is in the range of 0.5–1.0 nm without any controlling element.

Temperature-dependent Sellmeier equation for the refractive index of stoichiometric lithium tantalate.

We present a temperature-dependent Sellmeier equation for the refractive index of stoichiometric LiTaO3. The extraordinary refractive index, for the range 0.39-4.1 microm and for temperatures of 30-200 degrees C, are based on previously published data [Jpn. J. Appl. Phys. 41, 465 (2002)] and on measured data derived from quasi-phase-matched (QPM) resonances. We used the new Sellmeier coefficients that we obtained to calculate the QPM wavelengths for an optical parametric oscillator (OPO) based on periodically poled stoichiometric LiTaO3 pumped at 1064 nm. The measured wavelengths of the OPO were in good agreement with our predictions.

Temperature-dependent dispersion equations for KTiOPO4 and KTiOAsO4.

We have measured the thermal expansion and the temperature dependence of z and y components of the refractive index for KTiOPO4 and KTiOAsO4, in the wavelength range 532-1585 nm and temperature range 25-200 degrees C, using an interferometric technique. The measurements were used to derive temperature-dependent Sellmeier equations for the two materials. These equations predict with good agreement the temperature dependence of quasi-phase-matched nonlinear frequency converters.

Temperature-dependent Sellmeier equation for the index of refraction, n_e, in congruent lithium niobate

A Sellmeier equation for the extraordinary index of congruent lithium niobate is derived. The source data for the fit contain previously published data [Opt.Commun.17, 322 (1996); erratum 20, 188 (1997); J.Appl.Phys. 45, 3688 (1974)] and new measured tuning data for an optical parametric oscillator using periodically poled lithium niobate. Phase-matching predictions are accurate for temperatures between room temperature and 250 degrees C and wavelengths ranging from 0.4 to 5 mum .

Tunable ultraviolet radiation by second-harmonic generation in periodically poled lithium tantalate

We describe electric-field poling of fine-pitch ferroelectric domain gratings in lithium tantalate and characterization of nonlinear-optical properties by single-pass quasi-phase-matched second-harmonic generation (QPM SHG). With a 7.5-microm-period grating, the observed effective nonlinear coefficient for first-order QPM SHG of 532-nm radiation is 9 pm/V, whereas for a grating with a 2.625-microm period, 2.6 pm/V was observed for second-order QPM SHG of 325-nm radiation. These values are 100% and 55% of the theoretically expected values, respectively. We derive a temperature-dependent Sellmeier equation for lithium tantalate that is valid deeper into the UV than currently available results, based on temperature-tuning experiments at different QPM grating periods combined with refractive-index data in the literature.

Optical properties of lithium-rich lithium niobate fabricated by vapor transport equilibration

Lithium-rich lithium niobate of excellent optical homogeneity can be fabricated by a vapor transport equilibration (VTE) technique. The high-optical-quality, uniformly birefringent crystals noncritically phase match for second-harmonic generation of 532-nm radiation from 1064-nm Nd:YAG radiation at 238 degrees C. The refractive indexes and their temperature dependence have been measured and used to derive temperature-dependent Sellmeier equations, which predict noncritical phase matching for wavelengths as short as 976 nm to generate blue at 488 nm at room temperature. The Sellmeier equations accurately predict experimental phase-matching temperatures over a wide temperature range.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Temperature-dependent Sellmeier coefficients and coherence lengths for some chalcopyrite crystals

Temperature-dependent Sellmeier equations are useful for determining optical-design parameters of nonlinear optical devices. These coefficients as a function of temperature are calculated for three chalcopyrite crystals: ZnGeP2, CdGeP2, and CuGaS2. Coherence lengths for second harmonic generation as well as its temperature derivative are also presented for these crystals.

Temperature-dependent Sellmeier coefficients and nonlinear optics average power limit for germanium

A temperature-dependent Sellmeier equation is calculated for Ge. The accuracy of this temperature-dependent Sellmeier equation is compared with the internal consistency of the data. The phase-matching condition is discussed for four-wave mixing when two of the wave vectors are equal. The average power limit for four-wave mixing in a material like Ge is derived both for the case where one wave vector is fixed and for the case where two wave vectors are fixed. Using the derived Sellmeier equation, the average power limit for the four-wave mixing is calulated.

Temperature-dependent Sellmeier coefficients and coherence length for cadmium telluride*

A temperature-dependent Sellmeier equation is calculated for CdTe. Using the derived Sellmeier equation, the coherence length for second harmonic generation was calculated as well as the variation of the coherence length with temperature. The predicted coherence length is found to be in good agreement with measured values.

The temperature dependence of the refractive indices of pure lithium niobate

Two temperature dependent Sellmeier equations are derived to give the refractive indices of pure lithium niobate between 400 nm and 4000 nm, valid up to 500°C. Conditions for phase matched optical mixing processes are calculated and compared with experiment.