Temperature-Dependent Sellmeier Equations of IR Nonlinear Optical Crystal BaGa4Se7

Abstract

Abstract:The thermal dependent principal refractive indices of a new promising IR nonlinear optical crystal BaGa 4 Se 7 at wavelengths of 0.546, 0.5806, 0.644, 0.7065, 1.530, 1.970, and 2.325µm were measured by using the vertical incidence method within the temperature range from 25 to 150 • C. We derived equations of thermal refractive index coefficients as a function of wavelength that could be used to calculate the principal thermal refractive indices at different wavelengths. The temperature-dependent Sellmeier equations were also obtained and used to calculate the phase matching angles for the optical parametric process of BaGa 4 Se 7 crystal at different temperatures.

Mid-infrared spectrally-pure single-photon states generation from 22 nonlinear optical crystals

“…Expect from the 22 crystals we discussed above, we still find 6 kinds of new crystals in the MIR band: BGS, BGSe, BGGS, BGGSe, BGSS, and BGSSe [74][75][76][77][78]. They can be written as BaGa 4 X 7 (X=S, Se) and BaGa 2 M X 6 (M = Si, Ge; X=S, Se).…”

Widely tunable (2.6–10.4μm) BaGa4Se7optical parametric oscillator pumped by a Q-switched Nd:YLiF4laser

“…For obvious reasons due to the limited pump pulse power of the Nd:YLF laser (E p <1 mJ at the OPO) combined with decreasing parametric gain (resulting in higher threshold), we could not achieve the largest ever reported MIR tuning in [27]-up to 17 μm -obtained with a similar BGSe sample but a high-power Nd:YAG pump laser (E p >100 mJ). Very recently new dispersion formulae (Sellmeier equations) for BGSe have been proposed by three different groups [31][32][33], and their accuracy has been tested with our experimental phase-matching data taken at relatively low pump power, i.e. without any self-heating bias (due to residual absorption) introduced by highpower phase-matched data.…”

“…without any self-heating bias (due to residual absorption) introduced by highpower phase-matched data. In [32] thermo-optic Sellmeier equations for the three principal dielectric axis of BGSe were constructed for the first time, using direct index of refraction measurements of prisms maintained at some fixed temperatures spanning 25-150°C and employing the minimum deviation angle technique to derive the index of refraction. Mercury, Helium and Cadmium lamp lines between 0.546 μm and 2.325 μm were used for the temperature-dependent index measurement at a relative accuracy level of a few parts in 10 −4 .…”

“…Such large discrepancies find their origins in the customary inability of direct index measurements-even at the 10 −4 relative accuracy-to reflect experimental phase-matched data at less than a few degrees. Another origin of the inaccuracy of the Sellmeier data proposed in [32] is the limited MIR wavelength range of their index measurements (the longest wavelength being 2.325 μm).…”

Study of New Infrared Non-Linear Optical Crystal BaGa4Se7 Based on First Principle

“…Badikov [8,9] and others have successfully grown a high-quality BaGa 4 S 7 single crystal, and tested and calculated the phase matching of its refractive index and frequency doubling. However, due to the high melting point of BaGa 4 S 7 , the difficulty of crystal growth and the low nonlinear coefficient, researchers have found a BaGa 4 Se 7 crystal with a larger nonlinear coefficient, a more compact and stable structure [10]. Yao [11] et al synthesized the BaGa 4 Se 7 compound with β = 121.24 for the first time, and calculated the electronic and optical properties of BaGa 4 Se 7 through first principles.…”