LiNbO, crystals

Raman spectra are usually represented by the intensity of Stokes lines versus the shifted frequencies 12,. Figure 1.15 shows, as an example, the Raman spectrum of a lithium niobate (LiNbOs) crystal. The energies (given in wavenumber units, cm ) of the different phonons involved are indicated above the corresponding peaks. Particular emphasis will be given to those of higher energy, called effective phonons (883 cm for lithium niobate), as they actively participate in the nonradiative de-excitation processes of trivalent rare earth ions in crystals (see Section 6.3). 

In Table E7.5, the fluorescence lifetimes and quantum efficiencies measured from different excited states of the Pr + ( Po and D2) and Nd + (" Fs ji) ions in a LiNbOs crystal are listed, (a) Determine the multiphonon nonradiative rate from the 19/2 and In/2 states of the Er + ion in LiNbOs. (b) If a fluorescence lifetime of 535 /us is measured from the excited state Fs/2 of the Yb + ion in this crystal, estimate the radiative lifetime from this state. 

N.V. Sidorov, M.N. Palatnikov, V.T. Kalinnikov, Raman spectra and peculiarities of the structure of LiNbOs crystals, Optics and Spectroscopy 82, 38-45, (1997), in Russian. 

Boulon G (2004) Optical Transitions of Trivalent Neodymium and Chromium Centres in LiNbOs Crystal Host Material 107 1-25... 

Figure 10.3 Hexagonal and triangular domains tailored in congruent LiNbOs crystals by HVAFM.

Figure 10.8 fe domains induced by indirect EB writing in a LiNbOs crystal (Vo = 15kV,... 

Figure 10.9 Cracks exhibited by indirect eb writing in a LiNbOs crystal with Vo = 20 kV and = 200/tC/cm2.

Another method presented in this paper is the indirect eb method when the C -lace of a LiNbOs ferroelectric is preliminary coated by a highly defective layer of the amorphous photo-resist material pmma. The thickness of this dielectric layer is large enough to protect the LiNb03 from penetration of high energy electrons into the bulk. In the presented calculations and simulation a very limited number of electrons penetrated into the LiNbOs crystal, so most of the injected electron charge remains trapped in the pmma layer. 

Figure 5.1 (a) Single crystal form of LiNbO crystal (b) X-cut and -cut slices ... 

This non-linear optical method of generating frequency tunable infrared radiation was initially operated by Boyd and Ashkin,72 and developed by Pine73 into a very powerful spectroscopic tool. Radiation from a dye laser (v ) and radiation from a single-mode Ar ion laser (v ) are mixed in a LiNbO crystal. Their planes of... 

Cz Koepke, Wisniewski K, Dyl D, Grinberg M, Mahnowski M (2006) Evidence for existence of the trapped excition states in Pr -doped LiNbOs crystal. Opt Mater 28 137... 

LiNbOs crystal. Lithium niobate (LiNbOa) crystals (particularly in periodically poled stack configuration, or short PPLN) are widely used as firequency doublers for wavelengths X> pm (e.g. see Jimdt et al. (1991)), or in optical parametric oscillators (OPOs) pumped at 2 = 1064 nm, or at longer wavelengths (e.g. see Lin et al. (2004)). 

Table 1. LiNbOs crystal spec, (courtesy almaz optics, Inc.)...

Crystal LiNbOs Crystal cut Z Propagation direction Y Material Air Refractive index 1.00... 

The choice of the nonlinear medium depends on the wavelength of the pump laser and on its tuning range (Table 6.1). For SHG of lasers around A = 1 pm, 90° phase matching can be achieved with LiNbOs crystals, while for SHG of dye lasers around A = 0.5-0.6 pm, KDP crystals or ADA can be used. Figure 6.9 illustrates the dispersion curves no(A) and ne(A) of ordinary and extraordinary waves in KDP and LiNbOs, which show that 90° phase matching can be achieved in LiNbOs for Ap = 1.06 pm and in KDP for Ap 515nm [530]. 

Two collinear cw beams from a stable single-mode argon laser and a tunable single-mode dye laser are mixed in a LiNbOs crystal (Fig. 6.21). For 90° phase matching of collinear beams, the phase-matching condition... 

For a 5-cm long 90° phase-matched LiNbOs crystal pumped at Ap = 0.532 pm, threshold is at 38-mW pump power for the doubly-resonant cavity with 2% losses at coi and co. For the singly-resonant cavity, threshold increases by a factor of 100 to 3.8 W [609]. 

Figure 6.29 High-power cw OPO with periodically poled LiNbOs crystal with temperature control in a ring cavity [618]...

The whole spectral range of the difference spectrometer from 2.2 to 4.2 ym can be continuously covered by tuning the dye laser and the phase-matching temperature of the LiNbO crystal (-0.12°C/cm ). The infrared power is, according to (7.15) and (7.23), proportional to the product of the incident laser powers and to the square of the coherence length. For typical operating powers of 100 mW (argon laser) and 10 mW (dye laser) a few yW of in-... 

Coherent sources which are based on difference frequency generation (see Sect.7.2) have proved to be very successful in high-resolution infrared spectroscopy. One example is the differenoe frequency spectrometer developed by PINE [8.42,43], where the outputs from a single-mode argon laser and from a tunable single-mode cw dye laser are mixed in a LiNbO crystal (see Sect. 

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